IUPAC Condensed
H-Ile-Asn-Leu-Lys-Ala-Leu-Ala-Ala-Leu-Ala-Lys-Lys-xiIle-Leu-NH2
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lifitegrast
Xiidra (lifitegrast ophthalmic solution)

July 12, 2016
The U.S. Food and Drug Administration approved Xiidra (lifitegrast ophthalmic solution) for the treatment of signs and symptoms of dry eye disease, on Monday, July 11, 2016. Xiidra is the first medication in a new class of drugs, called lymphocyte function-associated antigen 1 (LFA-1) agonist, approved by the FDA for dry eye disease.
“Normal tear production is needed for clear vision and eye health,” said Edward Cox, M.D., director of the Office of Antimicrobial Products in the FDA’s Center for Drug Evaluation and Research. “This approval will provide a new treatment option for patients with dry eye disease.”
Dry eye disease includes a group of conditions in which the eye does not produce an adequate volume of tears or when the tears are not of the correct consistency. The chance of experiencing dry eye increases with age, affecting approximately five percent of the adult population age 30-40 and 10 to 15 percent of adults over age 65, and is more common among women. When severe and left untreated, this condition can lead to pain, ulcers or scars on the part of the eye called the cornea. Dry eye can make it more difficult to perform some activities, such as using a computer or reading for an extended period of time, and it can decrease tolerance for dry environments, such as the air inside an airplane.
The safety and efficacy of Xiidra was assessed in over a thousand patients, in four separate, randomized, controlled studies. These studies included patients 19–97 years of age, of which the majority were female (76 percent). Patients were randomized equally to receive either Xiidra eyedrops or placebo eyedrops, which were used twice a day for twelve weeks. The studies found that groups treated with Xiidra demonstrated more improvement in both the signs and the symptoms of eye dryness than the groups treated with placebo.
The most common side effects of Xiidra include eye irritation, discomfort or blurred vision and an unusual taste sensation (dysgeusia).
Dry eye disease does not routinely occur in children. Safety and efficacy in pediatric patients below the age of 17 years has not been studied.
Xiidra is manufactured by Shire US Inc., of Lexington, Massachusetts.
Common name: Lifitegrast, SAR 1118
LCI 699, LCI 699NX
Novartis Ag INNOVATOR
UNII-5YL4IQ1078, CAS 928134-65-0
MF, C13-H10-F-N3.H3-O4-P
MW, 325.2347
Aromatase inhibitor; Cytochrome P450 11B1 inhibitor

ACS Medicinal Chemistry Letters, 4(12), 1203-1207; 2013
Osilodrostat (INN, USAN) (developmental code name LCI-699) is an orally active, nonsteroidal corticosteroid biosynthesis inhibitorwhich is under development by Novartis for the treatment of Cushing’s syndrome and pituitary ACTH hypersecretion (a specific subtype of Cushing’s syndrome).[1][2] It specifically acts as a potent and selective inhibitor of aldosterone synthase (CYP11B2) and at higher dosages of 11β-hydroxylase (CYP11B1).[2] The drug was also under development for the treatment of heart failure, hypertension, and solid tumors, but development was discontinued for these indications.[1] As of 2017, osilodrostat is in phase III and phase II clinical trialsfor treatment of pituitary ACTH hypersecretion and Cushing’s syndrome, respectively.[1]
Osilodrostat, as modulators of 11-β-hydroxylase, useful for treating a disorder ameliorated 11-β-hydroxylase inhibition eg Cushing’s disease, hypertension, congestive heart failure, metabolic syndrome, liver diseases, cerebrovascular diseases, migraine headaches, osteoporosis or prostate cancer.
Novartis is developing osilodrostat, an inhibitor of aldosterone synthase and aromatase, for treating Cushing’s disease. In July 2016, osilodrostat was reported to be in phase 3 clinical development.
The somatostatin analog pasireotide and the 11β-hydroxylase inhibitor osilodrostat (LCI699) reduce cortisol levels by distinct mechanisms of action. There exists a scientific rationale to investigate the clinical efficacy of these two agents in combination. This manuscript reports the results of a toxicology study in rats, evaluating different doses of osilodrostat and pasireotide alone and in combination. Sixty male and 60 female rats were randomized into single-sex groups to receive daily doses of pasireotide (0.3mg/kg/day, subcutaneously), osilodrostat (20mg/kg/day, orally), osilodrostat/pasireotide in combination (low dose, 1.5/0.03mg/kg/day; mid-dose, 5/0.1mg/kg/day; or high dose, 20/0.3mg/kg/day), or vehicle for 13weeks. Mean body-weight gains from baseline to Week 13 were significantly lower in the pasireotide-alone and combined-treatment groups compared to controls, and were significantly higher in female rats receiving osilodrostat monotherapy. Osilodrostat and pasireotide monotherapies were associated with significant changes in the histology and mean weights of the pituitary and adrenal glands, liver, and ovary/oviduct. Osilodrostat alone was associated with adrenocortical hypertrophy and hepatocellular hypertrophy. In combination, osilodrostat/pasireotide did not exacerbate any target organ changes and ameliorated the liver and adrenal gland changes observed with monotherapy. Cmax and AUC0-24h of osilodrostat and pasireotide increased in an approximately dose-proportional manner. In conclusion, the pasireotide and osilodrostat combination did not exacerbate changes in target organ weight or toxicity compared with either monotherapy, and had an acceptable safety profile; addition of pasireotide to the osilodrostat regimen may attenuate potential adrenal gland hyperactivation and hepatocellular hypertrophy, which are potential side effects of osilodrostat monotherapy.

The somatostatin analog pasireotide and the 11β-hydroxylase inhibitor osilodrostat (LCI699) reduce cortisol levels by distinct mechanisms of action. There exists a scientific rationale to investigate the clinical efficacy of these two agents in combination. This manuscript reports the results of a toxicology study in rats, evaluating different doses of osilodrostat and pasireotide alone and in combination. Sixty male and 60 female rats were randomized into single-sex groups to receive daily doses of pasireotide (0.3 mg/kg/day, subcutaneously), osilodrostat (20 mg/kg/day, orally), osilodrostat/pasireotide in combination (low dose, 1.5/0.03 mg/kg/day; mid-dose, 5/0.1 mg/kg/day; or high dose, 20/0.3 mg/kg/day), or vehicle for 13 weeks. Mean body-weight gains from baseline to Week 13 were significantly lower in the pasireotide-alone and combined-treatment groups compared to controls, and were significantly higher in female rats receiving osilodrostat monotherapy. Osilodrostat and pasireotide monotherapies were associated with significant changes in the histology and mean weights of the pituitary and adrenal glands, liver, and ovary/oviduct. Osilodrostat alone was associated with adrenocortical hypertrophy and hepatocellular hypertrophy. In combination, osilodrostat/pasireotide did not exacerbate any target organ changes and ameliorated the liver and adrenal gland changes observed with monotherapy. Cmax and AUC0–24h of osilodrostat and pasireotide increased in an approximately dose-proportional manner.

In conclusion, the pasireotide and osilodrostat combination did not exacerbate changes in target organ weight or toxicity compared with either monotherapy, and had an acceptable safety profile; addition of pasireotide to the osilodrostat regimen may attenuate potential adrenal gland hyperactivation and hepatocellular hypertrophy, which are potential side effects of osilodrostat monotherapy.
The somatostatin class is a known class of small peptides comprising the naturally occurring somatostatin- 14 and analogues having somatostatin related activity, e.g. as disclosed by A.S. Dutta in Small Peptides, Vol.19, Elsevier (1993). By “somatostatin analogue” as used herein is meant any straight-chain or cyclic polypeptide having a structure based on that of the naturally occurring somatostatin- 14 wherein one or more amino acid units have been omitted and/or replaced by one or more other amino radical(s) and/or wherein one or more functional groups have been replaced by one or more other functional groups and/or one or more groups have been replaced by one or several other isosteric groups. In general, the term covers all modified derivatives of the native somatostatin- 14 which exhibit a somatostatin related activity, e.g. they bind to at least one of the five somatostatin receptor (SSTR), preferably in the nMolar range. Commonly known somatostatin analogs are octreotide, vapreotide, lanreotide, pasireotide.
Pasireotide, having the chemical structure as follow:
Pasireotide is called cyclo[{4-(NH2-C2H4-NH-CO-0-)Pro}-Phg-DTrp-Lys-Tyr(4-Bzl)- Phe], wherein Phg means -HN-CH(C6H5)-CO- and Bzl means benzyl, in free form, in salt or complex form or in protected form.
Cushing’s syndrome is a hormone disorder caused by high levels of Cortisol in the blood. This can be caused by taking glucocorticoid drugs, or by tumors that produce Cortisol or adrenocorticotropic hormone (ACTH) or CRH. Cushing’s disease refers to one specific cause of the syndrome: a tumor (adenoma) in the pituitary gland that produces large amounts of ACTH, which elevates Cortisol. It is the most common cause of Cushing’s syndrome, responsible for 70% of cases excluding glucocorticoid related cases. The significant decrease of Cortisol levels in Cushing’s disease patients on pasireotide support its potential use as a targeted treatment for Cushing’s disease (Colao et al. N Engl J Med 2012;366:32^12).
Compound A is potent inhibitor of the rate-limiting enzyme 1 1-beta-hydroxylase, the last step in the synthesis of Cortisol. WO 201 1/088188 suggests the potential use of compound A in treating a disease or disorder characterised by increased stress hormone levels and/or decreased androgen hormone levels, including the potential use of compound A in treating heart failure, cachexia, acute coronary syndrome, chronic stress syndrome, Cushing’s syndrome or metabolic syndrome.
Compound A, also called (R)-4-(6,7-Dihydro-5H-pyrrolo[l,2-c]imidazol-5-yl)-3-fluoro- benzonitrile, has formula (II).
Compound A can be synthesized or produced and characterized by methods as described in WO2007/024945.
PRODUCT PATENT
WO2007024945, hold protection in the EU states until August 2026, and expire in the US in March 2029 with US154 extension
PAPER
ACS Medicinal Chemistry Letters (2013), 4(12), 1203-1207.
http://pubs.acs.org/doi/abs/10.1021/ml400324c?source=chemport&journalCode=amclct

Aldosterone is a key signaling component of the renin-angiotensin-aldosterone system and as such has been shown to contribute to cardiovascular pathology such as hypertension and heart failure. Aldosterone synthase (CYP11B2) is responsible for the final three steps of aldosterone synthesis and thus is a viable therapeutic target. A series of imidazole derived inhibitors, including clinical candidate 7n, have been identified through design and structure–activity relationship studies both in vitro and in vivo. Compound 7n was also found to be a potent inhibitor of 11β-hydroxylase (CYP11B1), which is responsible for cortisol production. Inhibition of CYP11B1 is being evaluated in the clinic for potential treatment of hypercortisol diseases such as Cushing’s syndrome.
PATENT
silodrostat (LCI699; 4-[(5R)-6,7-dihydro-5H-pyrrolo[l,2-c]imidazol-5-yl]-3-fluoro-benzonitrile; CAS# 928134-65-0). Osilodrostat is a Ι Ι-β-hydroxylase inhibitor.
Osilodrostat is currently under investigation for the treatment of Cushing’s disease, primary aldosteronism, and hypertension. Osilodrostat has also shown promise in treating drug-resistant hypertension, essential hypertension, hypokalemia, hypertension, congestive heart failure, acute heart failure, heart failure, cachexia, acute coronary syndrome, chronic stress syndrome, Cushing’s syndrome, metabolic syndrome, hypercortisolemia, atrial fibrillation, renal failure, chronic renal failure, restenosis, sleep apnea, atherosclerosis, syndrome X, obesity, nephropathy, post-myocardial infarction, coronary heary disease, increased formation of collagen, cardiac or myocardiac fibrosis and/or remodeling following hypertension and endothelial dysfunction, Conn’s disease, cardiovascular diseases, renal dysfunction, liver diseases, cerebrovascular diseases, vascular diseases, retinopathy, neuropathy, insulinopathy, edema, endothelial dysfunction, baroreceptor dysfunction, migraine headaches, arrythmia, diastolic dysfunction, diastolic heart failure, impaired diastolic filling, systolic dysfunction, ischemia, hypertrophic cardiomyopathy, sudden cardia death, impaired arterial compliance, myocardial necrotic lesions, vascular damage, myocardial infarction, left ventricular hypertrophy, decreased ej ection fraction, cardiac lesions, vascular wall hypertrophy, endothelial thickening, fibrinoid, necrosis of coronary arteries, ectopic ACTH syndrome, change in adrenocortical mass, primary pigmented nodular adrenocortical disease (PPNAD), Carney complex (CNC), anorexia nervosa, chronic alcoholic poisoning, nicotine withdrawal syndrome, cocaine withdrawal syndrome, posttraumatic stress syndrome, cognitive impairment after a stroke or cortisol-induced mineral corticoid excess, ventricular arrythmia, estrogen-dependent disorders, gynecomastia, osteoporosis, prostate cancer, endometriosis, uterine fibroids, dysfunctional uterine bleeding, endometrial hyperplasia, polycyctic ovarian disease, infertility, fibrocystic breast disease, breast cancer, and fibrocystic mastopathy. WO 2013109514; WO 2007024945; and WO 2011064376.

Osilodrostat
Osilodrostat is likely subject to extensive CYP45o-mediated oxidative metabolism. These, as well as other metabolic transformations, occur in part through polymorphically-expressed enzymes, exacerbating interpatient variability. Additionally, some metabolites of osilodrostat derivatives may have undesirable side effects. In order to overcome its short half-life, the drug likely must be taken several times per day, which increases the probability of patient incompliance and discontinuance. Adverse effects associated with osilodrostat include fatigue, nausea, diarrhea, headache, hypokalemia, muscle spasms, vomiting, abdominal discomfort, abdominal pain, arthralgia, arthropod bite, dizziness, increased lipase, and pruritis.
Scheme I

EXAMPLE 1
(R)-4-(6,7-dihvdro-5H-pyrrolo[l,2-elimidazol-5-yl)-3-fluorobenzonitrile
(osilodrostat)

[00144] 4-(bromomethyl)-3-fluorobenzonitrile: 3-Fluoro-4-methylbenzonitrile (40 g, 296 mmol), NBS (63.2 g, 356 mmol) and benzoyl peroxide (3.6 g, 14.8 mmol) were taken up in carbon tetrachloride (490 mL) and refiuxed for 16 h. The mixture was allowed to cool to room temperature and filtered. The filtrate was concentrated and purified via flash column chromatography (0-5% EtOAc/hexanes) to give 4-(bromomethyl)-3-fluorobenzonitrile (35.4 g, 56%).

[00145] 2-(l-trityl-lH-imidazol-4-yl)acetic acid: Trityl chloride (40 g, 143.88 mmol, 1.2 equiv) was added to a suspension of (lH-imidazol-4-yl) acetic acid hydrochloride (20 g, 123.02 mmol, 1.0 equiv) in pyridine (200 mL). This was stirred at 50 °C for 16 h. Then the mixture was cooled and concentrated under vacuum and the crude product was purified by recrystallization from ethyl acetate (1000 ml) to afford 42 g (90%) of 2-[l-(triphenylmethyl)-lH-imidazol-4-yl] acetic acid as an off-white solid. LCMS (ESI): m/z = 369.2 [M+H]+
Step 2

2 step 2
2-( 1 -trityl- lH-imidazol-4-yl)ethanol : 2-(l-Trityl-lH-imidazol-4-yl) acetic acid (42 g, 114.00 mmol, 1.0 equiv) was suspended in THF (420 mL) and cooled to 0 °C. To this was added BH3 (1M in THF, 228.28 mL, 2.0 equiv). The clear solution obtained was stirred at 0 °C for 60 min, then warmed to room temperature until LCMS indicated completion of the reaction. The solution was cooled again to 0 °C and quenched carefully with water (300 mL). The resulting solution was extracted with ethyl acetate (3 x 100 mL) and the organic layers combined and dried over anhydrous Na2S04 and evaporated to give a sticky residue which was taken up in ethanolamine (800 mL) and heated to 90 °C for 2 h. The reaction was transferred to a separatory funnel, diluted with EtOAc (1 L) and washed with water (3 x 600 mL). The organic phase was dried over anhydrous Na2S04 and evaporated afford 35 g (87%) of 2-[l-(triphenylmethyl)-lH-imidazol-4-yl]ethanol as a white solid, which was used in the next step without further purification. LCMS (ESI) : m/z = 355.1 [M+H]+.
Step 3
![]()
3 step 3 4
4-(2-(tert-butyldimethylsilyloxy)ethyl)-l-trityl-lH-imidazole: 2-(l-Trityl-lH-imidazol-4-yl) ethanol (35 g, 98.75 mmol, 1.00 equiv) was dissolved in DCM (210 mL). To this was added imidazole (19.95 g, 293.05 mmol, 3.00 equiv) and tert-butyldimethylsilylchloride (22.40 g, 149.27 mmol, 1.50 equiv). The mixture was stirred at room temperature until LCMS indicated completion of the reaction. Then the resulting solution was diluted with 500 mL of DCM. The resulting mixture was washed with water (3 x 300 mL). The residue was purified by a silica gel column, eluted with ethyl
acetate/petroleum ether (1 :4) to afford 40 g (77%) of 4-[2-[(tert-butyldimethylsilyl)oxy]ethyl]-l-(triphenylmethyl)-lH-imidazole as a white solid. LCMS (ESI) : m/z = 469.1 [M+H]+.
Step 4

4-((5-(2-(tert-butyldimethylsilyloxy )ethylVlH-iniidazol-l -vnmethylV3-fluorobenzonitrile: 4-(2-((tert-Butyldimethylsilanyl)oxy)ethyl)-l rityl-lH-irnidazole (40 g, 85.34 mmol, 1.00 equiv) and 4-(Bromomethyl)-3-fluorobenzonitrile (27.38 g, 127.92 mmol, 1.50 equiv) obtained as a product of step 0, were dissolved in MeCN (480 mL) and DCM (80 mL), and stirred at room temperature for 48 h. Et2NH (80 mL) and MeOH (480 mL) were then added and the solution was warmed 80 °C for 3 h. The solution was evaporated to dryness and the residue was purified via flash column chromatography (EtOAc/hexanes 1 :5 to EtOAc) to afford 4-((5-(2-((tert-Butyldimethylsilanyl)oxy)ethyl)-lH-imidazol-l -yl)methyl)-3-fluorobenzonitrile (15 g, 50%). ¾ NMR (400 MHz, CDCh) δ: 7.67 (s, 1H), 7.43 (m, 2H), 6.98 (s, 1H), 6.88-6.79 (m, 1H), 5.34 (s, 2H), 3.79 (t, J= 8.0 Hz, 2H), 2.67 (t, J = 8.0 Hz, 2H), 0.88 (s, 9H), 0.02 (s, 6H). LCMS (ESI) : m/z = 360.1 [M+H]+.
Step 5

5 6
Methyl 2-(5-(2-(tert-butyldimethylsilyloxy)ethyl)-lH-imidazol-l -yl)-2-(4-cvano-2-fluorophenvDacetate: 4-((5-(2-((tert-Butyldimethylsilanyl)oxy)ethyl)-lH-imidazol-l -yl)methyl)-3-fluorobenzonitrile (15 g, 41.72 mmol, 1.00 equiv) was dissolved in anhydrous THF (150 mL) and stirred at -78 °C, then a THF solution of LiHMDS (75 mL, 1.80 equiv, 1.0 M) was added dropwise over 15 min. After 30 min, methyl cyanoformate (4.3 g, 45.50 mmol, 1.10 equiv) was added dropwise over 10 min and the solution was stirred at -78 °C for 2 h. The excess LiHMDS was quenched with aqueous saturated NH4CI and the mixture was allowed to warm to room temperature. The mixture was then diluted with EtOAc and washed
with aqueous saturated NH4CI (200 mL). The organic layers was dried over anhydrous Na2S04 and evaporated. The crude residue was purified via flash column chromatography (EtOAc/PE 3: 10 to EtOAc) to give methyl 2-(5-(2-((tert-butyldimethylsilanyl)oxy)ethyl)-lH-imidazol-l-yl)-2-(4-cyano-2-fluorophenyl) acetate (15 g, 86%) as a light yellow solid.
¾ NMR (400 MHz, CDCL3) δ: 7.66 (s, 1H), 7.54-7.43 (m, 2H), 7.15 (t, J= 8.0 Hz 1H), 6.93 (s, 1H), 6.47 (s, 1H), 3.88-3.74 (m, 5H), 2.81-2.62 (m, 2H), 0.89 (s, 9H), 0.05 (s, 6H) . LCMS (ESI) : m/z = 418.2 [M+H]+.
Step 6

Methyl 2-(4-cvano-2-fluorophenyl)-2-(5-(2-hvdroxyethyl)-lH-imidazol-l-yl) acetate: Methyl 2-(5-(2-((tert-butyldimethylsilanyl)oxy)ethyl)-lH-imidazol-l-yl)-2-(4-cyano-2-fiuorophenyl)acetate (15 g, 35.92 mmol, 1.00 equiv) was added to a solution of HCl in 1,4-dioxane (89 mL, 4.0 M, 359.2 mmol) at 0 °C and the mixture was allowed to warm to room temperature and stirred for 2 h. The solution was concentrated to dryness to give the crude alcohol, methyl 2-(4-cyano-2-fluorophenyl )-2-(5-(2 -hydroxy ethyl)-lH-imidazol-l-yl)acetate (10 g, 92%), which was used without further purification. LCMS: m/z = 304.0 [M+H]+.
Step 7

7 8
Methyl 2-(4-cvano-2-fluorophenyl)-2-(5-(2-(methylsulfonyloxy)ethyl)-lH-imidazol-l-yl) acetate: The crude methyl 2-(4-cyano-2-fluorophenyl )-2-(5-(2-hydroxyethyl)-lH-imidazol-l-yl)acetate (10 g, 32.97 mmol, 1.00 equiv) was dissolved in DCM (200 mL) and stirred at 0 °C, then Et3N (20 g, 197.65 mmol, 6.00 equiv) and
methanesulfonyl chloride (4.52 g, 39.67 mmol, 1.20 equiv) were added. After completion of the reaction, the solution was diluted with DCM and washed with aqueous saturated
NaHCC . The organic layer was dried over anhydrous Na2S04, filtered and evaporated to give the crude methyl 2-(4-cyano-2-fluorophenyl)-2-(5-(2-((methylsulfonyl)oxy)ethyl)-lH-imidazol-l-yl)acetate (11.43 g, 91%), which was used in the next step without further purification. LCMS (ESI) : m/z = 382.0 [M+H]+.
Step 8

Methyl 5-(4-cvano-2-fluorophenyl)-6.7-dihvdro-5H-pyrrolo[1.2-elimidazole-5-carboxylate: The crude methyl 2-(4-cyano-2 -fluorophenyl )-2-(5-(2- ((methylsulfonyl)oxy)ethyl)-lH-imidazol-l-yl)acetate (11.43 g, 29.97 mmol, 1.00 equiv) was dissolved in MeCN (550 mL) and then K2CO3 (12.44 g, 90.01 mmol, 3.00 equiv), Nal (13.50 g, 90.00 mmol, 3.00 equiv) and Et3N (9.09 g, 89.83 mmol, 3.00 equiv) were added. The reaction was stirred at 80 °C for 42 h. The mixture was filtered. The solids were washed with DCM. The filtrate was concentrated and purified by flash column chromatography (EtOAc) to give methyl 5-(4-cyano-2-fluorophenyl)-6,7-dihydro-5H-pyrrolo[l,2-c]imidazole-5-carboxylate (4.2 g, 49% in 3 steps).
[00153] ¾ NMR (400 MHz, CDCb) δ: 7.61 (s, 1H), 7.47-7.47 (m, 2H), 6.88 (s, 1H), 6.79-6.75 (m, 1H), 4.17-4.12 (m, 1H), 3.87 (s, 3H), 3.78-3.70 (m, 1H), 3.08-3.02 (m, 1H), 2.84-2.71 (m, 2H). LCMS (ESI) : m/z = 286.0 [M+H]+.
Step 9

10
4-(6.7-dihvdro-5H-pyrrolo[1.2-elimidazol-5-yl)-3-fluorobenzonitrile: To a 40-mL sealed tube, was placed methyl 5-(4-cyano-2-fluorophenyl)-5H,6H,7H-pyrrolo[l,2-c]imidazole-5-carboxylate (1 g, 3.51 mmol, 1.00 equiv), DMSO (10 mL), water (5 mL). The final reaction mixture was irradiated with microwave radiation for 40 min at 140 °C. The resulting solution was diluted with 100 mL of EtOAc. The resulting mixture was washed with (3 x 20 mL) brine, dried over anhydrous Na2S04, filtered and concentrated. The residue was purified by a silica gel column, eluted with ethyl acetate/petroleum ether (4: 1) to afford 420 mg (44%) of 5-(4-cyano-2-fluorophenyl)-5H,6H,7H-pyrrolo[l,2-c]irnidazole-5-carboxylic acid as a light yellow solid.
¾ NMR (400 MHz, CDCL3) δ: 7.55-7.28 (m, 3H), 6.90-6.85 (m, 2H), 5.74-5.71 (m, 1H), 3.25-3.15 (m, 1H), 3.02-2.92 (m, 2H), 2.58-2.50 (m, 1H). LCMS (ESI) : m/z = 228.2 [M+H]+.
Step 10

10
(R)-4-(6 -dihvdro-5H-pyrrolo[1.2-elirnidazol-5-yl)-3-fluorobenzonitrile:
Resolution of the enantiomers of the title compound (300 mg) was performed by chiral HPLC: Column, Chiralpak IA2, 2*25cm, 20um; mobile phase, Phase A: Hex (50%, 0.1% DEA), Phase B: EtOH (50%) ; Detector, UV 254/220 nm to afford the (S)-enantiomer (RT = 17 min) and the (R)-enantiomer (97.6 mg, desired compound) (RT = 21 min).
¾ NMR (400 MHz, DMSO-<4) δ: 7.98-7.95 (m, 1H), 7.70-7.69 (m, 1H), 7.50 (s, 1H), 6.87 (t, J= 8.0 Hz, 1H), 6.70 (s, 1H), 5.79-5.76 (m, 1H), 3.15-3.06 (m, 1H), 2.92-2.74 (m, 2H), 2.48-2.43 (m, 1H). LCMS (ESI) : m/z = 228.1 [M+H]+.
PATENT
WO2013/153129
https://www.google.com/patents/WO2013153129A1?cl=en
PATENT
WO2007/024945
http://www.google.co.in/patents/WO2007024945A1?cl=en
PATENT
Aspect (iii) of the present invention relates to phosphate salt or nitrate salt of 4-(R)-(6,7-dihydro-5H-pyrrolo[1,2-c]imidazol-5-yl)-3-fluoro-benzonitrile according to Formula (III)
abbreviated as ‘{drug3}’. In particular, the present invention relates to crystalline form of phosphate salt of 4-(R)-(6,7-dihydro-5H-pyrrolo[1,2-c]imidazol-5-yl)-3-fluoro-benzonitrile, abbreviated as ‘{drug3a}’; to crystalline Form A of phosphate salt of 4-(R)-(6,7-dihydro-5H-pyrrolo[1,2-c]imidazol-5-yl)-3-fluoro-benzonitrile, abbreviated as ‘{drug3b}’; to crystalline Form B of phosphate salt of 4-(R)-(6,7-dihydro-5H-pyrrolo[1,2-c]imidazol-5-yl)-3-fluoro-benzonitrile, abbreviated as ‘{drug3c}’; to crystalline Form C of phosphate salt of 4-(R)-(6,7-dihydro-5H-pyrrolo[1,2-c]imidazol-5-yl)-3-fluoro-benzonitrile, abbreviated as ‘{drug3d}’; to crystalline Form D of phosphate salt of 4-(R)-(6,7-dihydro-5H-pyrrolo[1,2-c]imidazol-5-yl)-3-fluoro-benzonitrile, abbreviated as ‘{drug3e}’; to crystalline Form E of phosphate salt of 4-(R)-(6,7-dihydro-5H-pyrrolo[1,2-c]imidazol-5-yl)-3-fluoro-benzonitrile, abbreviated as ‘{drug3f}’; to crystalline Form F of phosphate salt of 4-(R)-(6,7-dihydro-5H-pyrrolo[1,2-c]imidazol-5-yl)-3-fluoro-benzonitrile, abbreviated as ‘{drug3g}’; to crystalline Form G of phosphate salt of 4-(R)-(6,7-dihydro-5H-pyrrolo[1,2-c]imidazol-5-yl)-3-fluoro-benzonitrile, abbreviated as ‘{drug3h}’; to crystalline Form H of phosphate salt of 4-(R)-(6,7-dihydro-5H-pyrrolo[1,2-c]imidazol-5-yl)-3-fluoro-benzonitrile, abbreviated as ‘{drug3i}’; and to crystalline form of nitrate salt of 4-(R)-(6,7-dihydro-5H-pyrrolo[1,2-c]imidazol-5-yl)-3-fluoro-benzonitrile, abbreviated as ‘{drug3j}’. {drug3a}, {drug3b}, {drug3c}, {drug3d}, {drug3e}, {drug3f}, {drug3g}, {drug3h}, {drug3i}, and {drug3j} are specific forms falling within the definition of {drug3}. Aspect (iii) of the invention is separate from aspects (i), (ii), (iv), (v), (vi), (vii), and (viii) of the invention. Thus, all embodiments of {drug3a}, {drug3b}, {drug3c}, {drug3d}, {drug3e}, {drug3f}, {drug3g}, {drug3h}, {drug3i}, and {drug3j}, respectively, are only related to {drug3}, but neither to {drug1}, nor to {drug2}, nor to {drug4}, nor to {drug5}, nor to {drug6}, nor to {drug7}, nor to {drug8}.
PAPER
doi:10.1016/j.taap.2015.05.004, http://www.sciencedirect.com/science/article/pii/S0041008X15001684
CLIPS
| WO2011088188A1 * | Jan 13, 2011 | Jul 21, 2011 | Novartis Ag | Use of an adrenal hormone-modifying agent |
| Reference | ||
|---|---|---|
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11: Lother A, Moser M, Bode C, Feldman RD, Hein L. Mineralocorticoids in the heart and vasculature: new insights for old hormones. Annu Rev Pharmacol Toxicol. 2015;55:289-312. doi: 10.1146/annurev-pharmtox-010814-124302. Epub 2014 Sep 10. Review. PubMed PMID: 25251996.
12: Cuevas-Ramos D, Fleseriu M. Treatment of Cushing’s disease: a mechanistic update. J Endocrinol. 2014 Nov;223(2):R19-39. doi: 10.1530/JOE-14-0300. Epub 2014 Aug 18. Review. PubMed PMID: 25134660.
13: Yin L, Hu Q, Emmerich J, Lo MM, Metzger E, Ali A, Hartmann RW. Novel pyridyl- or isoquinolinyl-substituted indolines and indoles as potent and selective aldosterone synthase inhibitors. J Med Chem. 2014 Jun 26;57(12):5179-89. doi: 10.1021/jm500140c. Epub 2014 Jun 5. PubMed PMID: 24899257.
14: Li W, Luo S, Rebello S, Flarakos J, Tse FL. A semi-automated LC-MS/MS method for the determination of LCI699, a steroid 11β-hydroxylase inhibitor, in human plasma. J Chromatogr B Analyt Technol Biomed Life Sci. 2014 Jun 1;960:182-93. doi: 10.1016/j.jchromb.2014.04.012. Epub 2014 Apr 30. PubMed PMID: 24814004.
15: Trainer PJ. Next generation medical therapy for Cushing’s syndrome–can we measure a benefit? J Clin Endocrinol Metab. 2014 Apr;99(4):1157-60. doi: 10.1210/jc.2014-1054. PubMed PMID: 24702012.
16: Bertagna X, Pivonello R, Fleseriu M, Zhang Y, Robinson P, Taylor A, Watson CE, Maldonado M, Hamrahian AH, Boscaro M, Biller BM. LCI699, a potent 11β-hydroxylase inhibitor, normalizes urinary cortisol in patients with Cushing’s disease: results from a multicenter, proof-of-concept study. J Clin Endocrinol Metab. 2014 Apr;99(4):1375-83. doi: 10.1210/jc.2013-2117. Epub 2013 Dec 11. PubMed PMID: 24423285.
17: Oki Y. Medical management of functioning pituitary adenoma: an update. Neurol Med Chir (Tokyo). 2014;54 Suppl 3:958-65. PubMed PMID: 26236804.
18: Schumacher CD, Steele RE, Brunner HR. Aldosterone synthase inhibition for the treatment of hypertension and the derived mechanistic requirements for a new therapeutic strategy. J Hypertens. 2013 Oct;31(10):2085-93. doi: 10.1097/HJH.0b013e328363570c. PubMed PMID: 24107737; PubMed Central PMCID: PMC3771574.
19: Brown NJ. Contribution of aldosterone to cardiovascular and renal inflammation and fibrosis. Nat Rev Nephrol. 2013 Aug;9(8):459-69. doi: 10.1038/nrneph.2013.110. Epub 2013 Jun 18. Review. PubMed PMID: 23774812; PubMed Central PMCID: PMC3922409.
20: van der Pas R, de Herder WW, Hofland LJ, Feelders RA. Recent developments in drug therapy for Cushing’s disease. Drugs. 2013 Jun;73(9):907-18. doi: 10.1007/s40265-013-0067-6. Review. PubMed PMID: 23737437.
| Clinical data | |
|---|---|
| Synonyms | LCI-699 |
| Routes of administration |
Oral |
| Identifiers | |
| CAS Number | |
| PubChem CID | |
| ChemSpider | |
| UNII | |
| ChEMBL | |
| Chemical and physical data | |
| Formula | C13H10FN3 |
| Molar mass | 227.24 g·mol−1 |
| 3D model (JSmol) | |
///////OSILODROSTAT, Novartis , osilodrostat, an inhibitor of aldosterone synthase and aromatase, treating Cushing’s disease, July 2016, phase 3 clinical development, LCI 699, 928134-65-0, 1315449-72-9, PHASE 3, LCI 699NX, LCI 699AZA, CYP11B1 CYP11B2
c1cc(c(cc1C#N)F)[C@H]2CCc3n2cnc3.OP(=O)(O)O
N#CC1=CC=C([C@H]2CCC3=CN=CN32)C(F)=C1

TEZACAFTOR, VX 661
CAS : 1152311-62-0;
l-(2,2-difluoro-l,3-benzodioxol-5-yl)-N-[l-[(2R)-2,3-dihydroxypropyl]-6-fluoro-2-(2-hydroxy-l,l-dimethylethyl)-lH-indol-5-yl]-cyclopropanecarboxamide).
(R)-1-(2,2-difluorobenzo[d][1,3]dioxol-5-yl)-N-(1-(2,3-dihydroxypropyl)-6-fluoro-2-(1-hydroxy-2-methylpropan-2-yl)-1H-indol-5-yl)cyclopropanecarboxamide
Cyclopropanecarboxamide, 1-(2,2-difluoro-1,3-benzodioxol-5-yl)-N-[1-[(2R)-2,3-dihydroxypropyl]-6-fluoro-2-(2-hydroxy-1,1-dimethylethyl)-1H-indol-5-yl]-
1-(2,2-difluoro-1,3-benzodioxol-5-yl)-N-[1-[(2R)-2,3-dihydroxypropyl]-6-fluoro-2-(1-hydroxy-2-methylpropan-2-yl)indol-5-yl]cyclopropane-1-carboxamide
Vertex (INNOVATOR)
UNII: 8RW88Y506K

In July 2016, this combination was reported to be in phase 3 clinical development.
Update
Symdeko (tezacaftor/ivacaftor) ; Vertex; For the treatment of cystic fibrosis , Approved February 2018
Tezacaftor, also known asVX-661, is CFTR modulator. VX-661 is potentially useful for treatment of cystic fibrosis disease. Cystic fibrosis (CF) is a genetic disease caused by defects in the CF transmembrane regulator (CFTR) gene, which encodes an epithelial chloride channel. The most common mutation, Δ508CFTR, produces a protein that is misfolded and does not reach the cell membrane. VX-661 can correct trafficking of Δ508CFTR and partially restore chloride channel activity. VX-661 is currently under Phase III clinical trial.
VX-661 is an orally available deltaF508-CFTR corrector in phase III clinical trials at Vertex for the treatment of cystic fibrosis in patients homozygous to the F508del-CFTR mutation
Novel deuterated analogs of a cyclopropanecarboxamide ie tezacaftor (VX-661), as modulators of cystic fibrosis transmembrane conductance regulator (CFTR) proteins, useful for treating a CFTR-mediated disorder eg cystic fibrosis.
VX-661 (CAS #: 1152311-62-0; l-(2,2-difluoro-l,3-benzodioxol-5-yl)-N-[l-[(2R)-2,3-dihydroxypropyl]-6-fluoro-2-(2-hydroxy-l,l-dimethylethyl)-lH-indol-5-yl]-cyclopropanecarboxamide). VX-661 is a cystic fibrosis transmembrane conductance regulator modulator. VX-661 is currently under investigation for the treatment of cystic fibrosis. VX-661 has also shown promise in treating sarcoglycanopathies, Brody’s disease, cathecolaminergic polymorphic ventricular tachycardia, limb girdle muscular dystrophy, asthma, smoke induced chronic obstructive pulmonary disorder, chronic bronchitis, rhinosinusitis, constipation, pancreatitis, pancreatic insufficiency, male infertility caused by congenital bilateral absence of the vas deferens (CBAVD), mild pulmonary disease, idiopathic pancreatitis, allergic bronchopulmonary aspergillosis (ABPA), liver disease, hereditary emphysema, hereditary hemochromatosis, coagulation-fibrinolysis deficiencies, such as protein C deficiency, type 1 hereditary angioedema, lipid processing deficiencies, such as familial hypercholesterolemia, type 1 chylomicronemia, abetalipoproteinemia, lysosomal storage diseases, such as I-cell disease/pseudo-Hurler, mucopolysaccharidoses, Sandhof/Tay-Sachs, Crigler-Najjar type II, polyendocrinopathy/hyperinsulinemia, diabetes mellitus, Laron dwarfism, myeloperoxidase deficiency, primary hypoparathyroidism, melanoma, glycanosis CDG type 1, congenital hyperthyroidism, osteogenesis imperfecta, hereditary hypofibrinogenemia, ACT deficiency, diabetes insipidus (DI), neurohypophyseal DI, nephrogenic DI, Charcot-Marie tooth syndrome, Pelizaeus-Merzbacher disease, neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, progressive supranuclear palsy, Pick’s disease, polyglutamine neurological disorders such as Huntington’s, spinocerebellar ataxia type I, spinal and bulbar muscular atrophy, dentatombral pallidoluysian, and myotonic dystrophy, as well as spongifiorm encephalopathies, such as hereditary Creutzfeldt- Jakob disease (due to prion protein processing defect), Fabry disease, Gerstrnarm-Straussler-Scheinker syndrome, chronic obstructive pulmonary disorder, dry-eye disease, or Sjogren’s disease, osteoporosis, osteopenia, bone healing and bone growth (including bone repair, bone regeneration, reducing bone resorption and increasing bone deposition), Gorham’s Syndrome, chloride channelopathies such as myotonia congenita (Thomson and Becker forms), Bartter’s
syndrome type III, Dent’s disease, hyperekplexia, epilepsy, lysosomal storage disease, Angelman syndrome, and primary ciliary dyskinesia (PCD), a term for inherited disorders of the structure and/or function of cilia, including PCD with situs inversus (also known as Kartagener syndrome), PCD without situs inversus, and ciliary aplasia. WO 2014086687; WO2013185112.

VX-661

VX-661 is likely subject to extensive CYP45o-mediated oxidative metabolism. These, as well as other metabolic transformations, occur in part through polymorphically-expressed enzymes, exacerbating interpatient variability. Additionally, some metabolites of VX-661 may have undesirable side effects. In order to overcome its short half-life, the drug likely must be taken several times per day, which increases the probability of patient incompliance and discontinuance.Deuterium Kinetic Isotope Effect
PATENT
Scheme I


EXAMPLE 1
(R)-l-(2,2-difluorobenzo[dl[l,31dioxol-5-vn-N-(l-q,3-dihvdroxypropyn-6-fluoro-2-(l- hvdroxy-2-methylpropan-2-yl)-lH-indol-5-yl)cvclopropanecarboxamide
(VX-661)

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Methyl 2.2-difluorobenzo[dl [1.31dioxole-5-carboxylate: To a 200 mL pressure tank reactor (10 atm. in CO), was placed 5-bromo-2,2-difluoro-2H-l,3-benzodioxole (20.0 g, 84.4 mmol, 1.00 equiv), methanol (40 mL), triethylamine (42.6 g, 5.00 equiv.), Pd2(dba)3 (1.74 g, 1.69 mmol, 0.02 equiv), Pd(dppf)Cl2 (1.4 g, 1.69 mmol, 0.02 equiv.). The resulting solution was stirred at 85 °C under an atmosphere of CO overnight and the reaction progress was monitored by GCMS. The reaction mixture was cooled. The solids were filtered out. The organic phase was concentrated under vacuum to afford 17.5 g of methyl 2,2-difluoro-2H-l,3-benzodioxole-5-carboxylate as a crude solid, which was used directly in the next step. Step 2
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2 step 2 3
(2.2-difluorobenzo[dl [ 1.31 dioxol-5 -vDmethanol : To a 500mL 3-necked round-bottom flask purged and maintained with an inert atmosphere of nitrogen were placed methyl 2,2-difluoro-2H-l,3-benzodioxole-5-carboxylate (17.5 g, 81.01 mmol, 1.00 equiv.), tetrahydrofuran (200 mL). This was followed by the addition of L1AIH4 (6.81 mg, 162.02 mmol, 2.00 equiv.) at 0 °C. The resulting solution was stirred for 1 h at 25 °C and monitored by GCMS. The reaction mixture was cooled to 0 °C until GCMS indicated the completion of the reaction. The pH value of the solution was adjusted to 8 with sodium hydroxide (1 mol/L). The solids were filtered out. The organic layer combined and concentrated under vacuum to afford 13.25 g (87%) of (2,2-difluoro-2H-l,3-benzodioxol-5-yl)methanol as yellow oil.
Step 3
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step 3
5-(chloromethyl)-2.2-difluorobenzo[diri.31dioxole: (2.2-difluoro-2H-1.3-benzodioxol-5-yl)methanol (13.25 g, 70.4 mmol, 1.00 equiv.) was dissolved in DCM (200 mL). Thionyl chloride (10.02 g, 1.20 equiv.) was added to this solution. The resulting mixture was stirred at room temperature for 4 hours and then concentrated under vacuum. The residue was then diluted with DCM (500 mL) and washed with 2 x 200 mL of sodium bicarbonate and 1 x 200 mL of brine. The mixture was dried over anhydrous sodium sulfate, filtered and evaporated to afford 12.36 g (85%) of 5-(chloromethyl)-2,2-difluoro-2H-l ,3-benzodioxole as yellow oil.
Step 4
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step 4 5
[00160] 2-(2.2-difluorobenzordi ri .31dioxol-5-yl)acetonitrile: 5-(chloromethyl)-2,2-difluoro-2H-l,3-benzodioxole (12.36 g, 60 mmol, 1.00 equiv.) was dissolved in DMSO (120 mL). This was followed by the addition of NaCN (4.41 g, 1.50 equiv.) with the inert temperature below 40 °C. The resulting solution was stirred for 2 hours at room temperature. The reaction progress was monitored by GCMS. The reaction was then quenched by the addition of 300 mL of water/ice. The resulting solution was extracted with 3 x 100 mL of ethyl acetate. The organic layers combined and washed with 3 x 100 mL brine dried over anhydrous sodium sulfate and concentrated under vacuum to afford 10.84 g (92%) of 2-(2,2-difluoro-2H-l ,3-benzodioxol-5-yl)acetonitrile as brown oil.
Step 5

l -(2.2-difluoro-2H-1.3-benzodioxol-5-yl)cvclopropane-l -carbonitrile: To a 100 mL round-bottom flask purged and maintained with an inert atmosphere of nitrogen, were placed 2-(2,2-difluoro-2H-l ,3-benzodioxol-5-yl)acetonitrile (10.84 g, 55 mmol, 1.00 equiv.),
NaOH (50%) in water), 1 -bromo-2-chloroethane (11.92g, 82.5 mmol, 1.50 equiv.), BmNBr
(361 mg, 1.1 mmol, 0.02 equiv.). The resulting solution was stirred for 48 h at 70 °C. The reaction progress was monitored by GCMS. The reaction mixture was cooled. The resulting solution was extracted with 3 x 200 mL of ethyl acetate and the organic layers combined. The resulting mixture was washed with 1 x 200 mL of brine. The mixture was dried over anhydrous sodium sulfate and concentrated under vacuum to afford 10.12g of 1 -(2,2-difluoro-2H-l,3-benzodioxol-5-yl)cyclopropane-l-carbonitrile as brown oil.
Step 6

[00162] l-(2.2-difluoro-2H-1.3-benzodioxol-5-yl)cvclopropane-l-carboxylic acid: To a 250-mL round-bottom flask purged and maintained with an inert atmosphere of nitrogen, was placed l-(2,2-difluoro-2H-l,3-benzodioxol-5-yl)cyclopropane-l-carbonitrile (10.12 g, 45.38 mmol, 1.00 equiv), 6 N NaOH (61 mL) and EtOH (60 mL). The resulting solution was stirred for 3 h at 100 °C. The reaction mixture was cooled and the pH value of the solution was adjusted to 2 with hydrogen chloride (1 mol/L) until LCMS indicated the completion of the reaction. The solids were collected by filtration to afford 9.68 g (88%) of l-(2,2-difluoro-2H-l,3-benzodioxol-5-yl)cyclopropane-l-carboxylic acid as a light yellow solid.
Step 7

[00163] l-(2.2-difluoro-2H-1.3-benzodioxol-5-yl)cvclopropane-l-carbonyl chloride; To a solution of l-(2,2-difluoro-2H-l,3-benzodioxol-5-yl)cyclopropane-l-carboxylic acid (687 mg, 2.84 mmol, 1.00 equiv.) in toluene (5 mL) was added thionyl chloride (1.67 g, 5.00 equiv.). The resulting solution was stirred for 3h at 65 °C. The reaction mixture was cooled and concentrated under vacuum to afford 738 mg (99%) of l-(2,2-difluoro-2H-l,3-benzodioxol-5-yl)cyclopropane-l-carbonyl chloride as a yellow solid.
Step 8
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9 STEP 8 10
2-methyl-4-(trimethylsilyl)but-3-vn-2-ol: To a solution of ethynyltrimethylsilane (20 g, 203.63 mmol, 1.00 equiv) in THF (100 mL) was added n-BuLi (81 mL, 2.5M in THF)
dropwise with stirring at -78 °C. Then the resulting mixture was warmed to 0 °C for 1 h with stirring and then cooled to -78 °C. Propan-2-one (11.6 g, 199.73 mmol, 1.00 equiv.) was added dropwise with the inert temperature below -78 °C. The resulting solution was stirred at -78 °C for 3 h. The reaction was then quenched by the addition of 100 mL of water and extracted with 3 x 100 mL of MTBE. The combined organic layers was dried over anhydrous sodium sulfate and concentrated under vacuum to afford 28 g (90%) of 2-methyl-4-(trimethylsilyl)but-3-yn-2-ol as an off-white solid. ¾ NMR (400 MHz, CDCh) δ: 1.50 (s, 6H), 1.16-1.14 (m, 9H).
Step 9
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step 9
10
(3-chloro-3-methylbut-l-vnvntrimethylsilane: To a lOOmL round-bottom flask, was placed 2-methyl-4-(trimethylsilyl) but-3-yn-2-ol (14 g, 89.57 mmol, 1.00 equiv.), cone. HC1 (60 mL, 6.00 equiv.). The resulting solution was stirred for 16 h at 0 °C. The resulting solution was extracted with 3 x 100 mL of hexane. The combined organic layers was dried over anhydrous sodium sulfate and concentrated under vacuum to afford 8 g (51%) of (3-chloro-3-methylbut-l-yn-l-yl)trimethylsilane as light yellow oil. ¾ NMR (400 MHz, CDCh) δ: 1.84 (s, 6H), 1.18-1.16 (m, 9H).
Step 10
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step 10
11 12
(4-(benzyloxy)-3.3-dimethylbut-l-vnyl)trimethylsilane: Magnesium turnings (1.32 g, 1.20 equiv) were charged to a 250-mL 3-necked round-bottom flask and then suspended in THF (50 mL). The resulting mixture was cooled to 0 °C and maintained with an inert atmosphere of nitrogen. (3-chloro-3-methylbut-l-yn-l-yl)trimethylsilane (8 g, 45.78 mmol, 1.00 equiv.) was dissolved in THF (50 mL) and then added dropwise to this mixture with the inert temperature between 33-37 °C. The resulting solution was stirred at room temperature for an addition 1 h before BnOCH2Cl (6.45 g, 41.33 mmol, 0.90 equiv.) was added dropwise with the temperature below 10 °C. Then the resulting solution was stirred for 16 h at room temperature. The reaction was then quenched by the addition of 50 mL of water and extracted with 3 x 100 mL of hexane. The combined organic layers was dried over
anhydrous sodium sulfate and concentrated under vacuum to afford 10 g (84%) of [4-(benzyloxy)-3,3-dimethylbut-l-yn-l-yl]trimethylsilane as light yellow oil. ¾ NMR (400 MHz, CDCh) δ: 7.37-7.35 (m, 5H), 4.62 (s, 2H), 3.34 (s, 2H), 1.24 (s, 6H), 0.17-0.14 (m, 9H).
Step 11
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((2.2-dimethylbut-3-vnyloxy)methyl)benzene: To a solution of [4-(benzyloxy)-3,3-dimethylbut-l-yn-l-yl]trimethylsilane (10 g, 38.40 mmol, 1.00 equiv) in methanol (100 mL) was added potassium hydroxide (2.53 g, 38.33 mmol, 1.30 equiv). The resulting solution was stirred for 16 h at room temperature. The resulting solution was diluted with 200 mL of water and extracted with 3 x 100 mL of hexane. The organic layers combined and washed with 1 x 100 mL of water and then dried over anhydrous sodium sulfate and concentrated under vacuum to afford 5 g (69%) of [[(2,2-dimethylbut-3-yn-l-yl)oxy]methyl]benzene as light yellow oil. ¾ NMR (300 MHz, D20) δ: 7.41-7.28 (m, 5H) , 4.62 (s, 2H), 3.34 (s, 2H), 2.14 (s, 1H), 1.32-1.23 (m, 9H).
Step 12
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14 15
methyl 2.2-difluorobenzo[d1[1.31dioxole-5-carboxylate: To a solution of 3-fluoro-4-nitroaniline (6.5 g, 41.64 mmol, 1.00 equiv) in chloroform (25 mL) and AcOH (80 mL) was added Bn (6.58 g, 41.17 mmol, 1.00 equiv.) dropwise with stirring at 0 °C in 20 min. The resulting solution was stirred for 2 h at room temperature. The reaction was then quenched by the addition of 150 mL of water/ice. The pH value of the solution was adjusted to 9 with sodium hydroxide (10 %). The resulting solution was extracted with 3 x 50 mL of ethyl acetate and the organic layers combined. The resulting mixture was washed with 1 x 50 mL of water and 2 x 50 mL of brine, dried over anhydrous sodium sulfate and concentrated under vacuum. The crude product was re-crystallized from PE/EA (10: 1) to afford 6 g (61%) of 2-bromo-5-fluoro-4-nitroaniline as a yellow solid.
Step 13

(R)-l-(benzyloxy)-3-(2-bromo-5-fluoro-4-nitrophenylamino)propan-2-ol: 2-bromo-5-fluoro-4-nitroaniline (6.00 g, 25.56 mmol, 1.00 equiv.), Zn(C104)2 (1.90 g, 5.1 mmol, 0.20 equiv.), 4A Molecular Sieves (3 g), toluene (60 mL) was stirred at room temperature for 2 h and maintain with an inert atmosphere of N2 until (2R)-2-[(benzyloxy)methyl]oxirane (1.37 g, 8.34 mmol, 2.00 equiv.) was added. Then the resulting mixture was stirred for 15 h at 85 °C. The reaction progress was monitored by LCMS. The solids were filtered out and the resulting solution was diluted with 20 mL of ethyl acetate. The resulting mixture was washed with 2 x 20 mL of Sat. NH4CI and 1 x 20 mL of brine. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was purified by a silica gel column, eluted with ethyl acetate/petroleum ether (1 :5) to afford 7.5 g (70%) of N-[(2R)-3-(benzyloxy)-2-hydroxypropyl]-2-bromo-5-fluoro-4-nitroaniline as a yellow solid.
Step 14

[00170] (R)-l-(4-amino-2-bromo-5-fluorophenylamino)-3-(benzyloxy)propan-2-ol: To a 250-mL round-bottom flask, was placed N-[(2R)-3-(benzyloxy)-2-hydroxypropyl]-2-bromo-5-fluoro-4-nitroaniline (7.5 g, 18.84 mmol, 1.00 equiv.), ethanol (80 mL), water (16 mL), NH4CI (10 g, 189 mmol, 10.00 equiv.), Zn (6.11 g, 18.84 mmol, 5.00 equiv.). The resulting solution was stirred for 4 h at 85 °C. The solids were filtered out and the resulting solution was concentrated under vacuum and diluted with 200 mL of ethyl acetate. The resulting mixture was washed with 1 x 50 mL of water and 2 x 50 mL of brine. The organic phase was dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was purified by a silica gel column, eluted with ethyl acetate/petroleum ether (1 :3) to afford 4.16 g (60%) of l-N-[(2R)-3-(benzyloxy)-2-hydroxypropyl]-2-bromo-5-fluorobenzene-l ,4-diamine as light yellow oil.
Step 15
TsO

(R)-4-(3-(benzyloxy)-2-hvdroxypropylamino)-5-bromo-2-fluorobenzenaminium 4-methylbenzenesulfonate: l-N-[(2R)-3-(benzyloxy)-2-hydroxypropyl]-2-bromo-5-fluorobenzene-l ,4-diamine (2 g, 5.42 mmol, 1.00 equiv.) was dissolved in dichloromethane (40 mL) followed by the addition of TsOH (1 g, 5.81 mmol, 1.10 equiv.). The resulting mixture was stirred for 16 h at room temperature and then concentrated under vacuum to afford 2.8 g (95%) of 4-[[(2R)-3-(benzyloxy)-2-hydroxypropyl]amino]-5-bromo-2-fluoroanilinium 4-methylbenzene-l -sulfonate as an off-white solid.
Step 16

(R)-l-(4-amino-2-(4-(benzyloxy)-3.3-dimethylbut-l-vnyl)-5-fluorophenylamino)-3-(benzyloxy)propan-2-ol: To a 100-mL round-bottom flask purged and maintained with an inert atmosphere of nitrogen, was placed 4-[[(2R)-3-(benzyloxy)-2-hydroxypropyl]amino]-5-bromo-2-fluoroanilinium 4-methylbenzene-l -sulfonate (2.9 g, 5.36 mmol, 1.00 equiv.), [[(2,2-dimethylbut-3-yn-l-yl)oxy]methyl]benzene (1.2 g, 6.37 mmol, 1.20 equiv.), Pd(OAc)2 (48 mg, 0.21 mmol, 0.04 equiv.), dppb (138 mg, 0.32 mmol, 0.06 equiv.), potassium carbonate (2.2 g, 15.92 mmol, 3.00 equiv.) and MeCN (50 mL). The resulting solution was stirred for 16 h at 80 °C. The solids were filtered out and the resulting mixture was concentrated under vacuum until LCMS indicated the completion of the reaction. The residue was purified by a silica gel column, eluted with ethyl acetate/petroleum ether (1 :4) to afford 2.2 g (86%) of l-N-[(2R)-3-(benzyloxy)-2-hydroxypropyl]-2-[4-(benzyloxy)-3,3-dimethylbut-l-yn-l-yl]-5-fluorobenzene-l ,4-diamine as a light brown solid.
Step 17

l-(2.2-difluoro-2H-1.3-benzodioxol-5-yl)cvclopropane-l-carboxylic acid: To a 40-mL vial purged and maintained with an inert atmosphere of nitrogen, was placed 1-N-[(2R)-3-(benzyloxy)-2-hydroxypropyl]-2-[4-(benzyloxy)-3,3-dimethylbut-l-yn-l-yl]-5-fluorobenzene-l,4-diamine (1 g, 2.1 mmol, 1.00 equiv.), MeCN (10 mL), Pd(MeCN)2Cl2 (82 mg, 0.32 mmol, 0.15 equiv.). The resulting solution was stirred for 12 h at 85 °C. The reaction progress was monitored by LCMS. The resulting mixture was concentrated under vacuum to afford 900 mg (crude) of (2R)-l-[5-amino-2-[l-(benzyloxy)-2-methylpropan-2-yl]-6-fluoro-lH-indol-l-yl]-3-(benzyloxy)propan-2-ol as a brown solid, which was used for next step without further purification.
Step 18

(R)-N-(l-(3-(benzyloxy)-2-hvdroxypropyl)-2-(l-(benzyloxy)-2-methylpropan-2-yl)-6-fluoro- lH-indol-5-yl)- 1 -(2.2-difluorobenzo[dl [ 1.31 dioxol-5-vDcvclopropanecarboxamide: To a 40 mL vial purged and maintained with an inert atmosphere of nitrogen, was placed (2R)-l-[5-amino-2-[l-(benzyloxy)-2-methylpropan-2-yl]-6-fluoro-lH-indol-l-yl]-3-(benzyloxy)propan-2-ol (800 mg, 1.68 mmol, 1.00 equiv.), dichloromethane (20 mL), TEA (508 mg, 5.04 mmol, 3.00 equiv.). l-(2,2-difiuoro-2H-l,3-benzodioxol-5-yl)cyclopropane-l-carbonyl chloride (524 mg, 2 mmol, 1.20 equiv.) was added to this mixture at 0 °C. The resulting solution was stirred for 2 h at 25 °C. The reaction progress was monitored by LCMS. The resulting solution was diluted with 20 mL of DCM and washed with 3 xlO mL of brine. The combined organic layers was dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was purified by a silica gel column, eluted with ethyl acetate/petroleum ether (1:5) to afford 400 mg (30%) of N-[l-[(2R)-3-(benzyloxy)-2-hydroxypropyl]-2-[l-(benzyloxy)-2-methylpropan-2-yl]-6-fluoro-lH-indol-5-yl]-l-(2,2-difluoro-2H-l,3-benzodioxol-5-yl)cyclopropane-l-carboxamide as a light yellow solid.
Step 19

(R)-l-(2,2-difluorobenzo[d] [l,3]dioxol-5-yl)-N-(l-(2,3-dihydroxypropyl)-6-fluoro-2-(l-hydroxy-2-methylpropan-2-yl)-lH-indol-5-yl)cyclopropanecarboxamide: To a 100-mL 3-necked round-bottom flask purged and maintained with an inert atmosphere of H2, were placed N-[l-[(2R)-3-(benzyloxy)-2-hydroxypropyl]-2-[l-(benzyloxy)-2-methylpropan-2-yl]-6-fluoro-lH-indol-5-yl]-l-(2,2-difluoro-2H-l,3-benzodioxol-5-yl)cyclopropane-l-carboxamide (400 mg, 0.77 mmol, 1.00 equiv.) dry Pd/C (300 mg) and MeOH (5 Ml, 6M HC1). The resulting mixture was stirred at room temperature for 2 h until LCMS indicated the completion of the reaction. The solids were filtered out and the resulting mixture was concentrated under vacuum. The residue was purified by prep-HPLC with the following conditions: Column, XBridge Prep C18 OBD Column 19 x 150 mm, 5um; mobile phase and Gradient, Phase A: Waters (0.1%FA ), Phase B: ACN; Detector, UV 254 nm to afford 126.1 mg (42.4%) of (R)-l-(2,2-difluorobenzo[d] [l,3]dioxol-5-yl)-N-(l-(2,3-dihydroxypropyl)-6-fluoro-2-(l-hydroxy-2-methylpropan-2-yl)-lH-indol-5-yl)cyclopropanecarboxamide as a light yellow solid.
¾ NMR (400 MHz, OMSO-de) δ: 8.32 (s, 1H), 7.54 (s, 1H), 7.41-7.38 (m, 2H), 7.34-7.31 (m, 2H), 6.22 (s, 1H), 5.03-5.02 (m, 1H), 4.93-4.90 (m, 1H), 4.77-4.75 (m, 1H), 4.42-4.39 (m, 1H), 4.14-4.08 (m, 1H), 3.91 (brs, 1H) , 3.64-3.57 (m, 2H), 3.47-3.40 (m, 2H), 1.48-1.46 (m, 2H), 1.36-1.32 (m, 6H), 1.14-1.12 (m, 2H).
LCMS: m/z = 521.2[M+H]+.
WO 2015160787
https://www.google.com/patents/WO2015160787A1?cl=en
PATENT
WO 2014014841
https://www.google.com/patents/WO2014014841A1?cl=en
All tautomeric forms of the Compound 1 are included herein. For example, Compound 1 may exist as tautomers, both of which are included herein:
Methods of Preparing Compound 1 Amorphous Form and Compound 1 Form A
Compound 1 is the starting point and in one embodiment can be prepared by coupling an acid chloride moiety with an amine moiety according to Schemes 1-4.
Scheme 1. Synthesis of the acid chloride moiety.
Toluene, H20, 70 °C
Bu4NBr
1. NaOH
2. HC1
Scheme 2. Synthesis of acid chloride moiety – alternative synthesis.
1. NaCN
2. H20
SOC1,
Scheme 3. Synthesis of the amine moiety.
Scheme 4. Formation of Compound 1.
Compound 1
Methods of Preparing Compound 1 Amorphous Form
Starting from Compound 1 , or even a crystalline form of Compound 1 , Compound 1 Amorphous Form may be prepared by rotary evaporation or by spray dry methods.
Dissolving Compound 1 in an appropriate solvent like methanol and rotary evaporating the methanol to leave a foam produces Compound 1 Amorphous Form. In some embodiments, a warm water bath is used to expedite the evaporation.
Compound 1 Amorphous Form may also be prepared from Compound 1 using spray dry methods. Spray drying is a process that converts a liquid feed to a dried particulate form. Optionally, a secondary drying process such as fluidized bed drying or vacuum drying, may be used to reduce residual solvents to pharmaceutically acceptable levels. Typically, spray drying involves contacting a highly dispersed liquid suspension or solution, and a sufficient volume of hot air to produce evaporation and drying of the liquid droplets. The preparation to be spray dried can be any solution, coarse suspension, slurry, colloidal dispersion, or paste that may be atomized using the selected spray drying apparatus. In a standard procedure, the preparation is sprayed into a current of warm filtered air that evaporates the solvent and conveys the dried product to a collector (e.g. a cyclone). The spent air is then exhausted with the solvent, or alternatively the spent air is sent to a condenser to capture and potentially recycle the solvent. Commercially available types of apparatus may be used to conduct the spray drying. For example, commercial spray dryers are manufactured by Buchi Ltd. And Niro (e.g., the PSD line of spray driers manufactured by Niro) (see, US 2004/0105820; US 2003/0144257).
Spray drying typically employs solid loads of material from about 3% to about 30% by weight, (i.e., drug and excipients), for example about 4% to about 20% by weight, preferably at least about 10%. In general, the upper limit of solid loads is governed by the viscosity of (e.g., the ability to pump) the resulting solution and the solubility of the components in the solution. Generally, the viscosity of the solution can determine the size of the particle in the resulting powder product.
Techniques and methods for spray drying may be found in Perry’s Chemical
Engineering Handbook, 6th Ed., R. H. Perry, D. W. Green & J. O. Maloney, eds.), McGraw-Hill book co. (1984); and Marshall “Atomization and Spray-Drying” 50, Chem. Eng. Prog. Monogr. Series 2 (1954). In general, the spray drying is conducted with an inlet temperature of from about 60 °C to about 200 °C, for example, from about 95 °C to about 185 °C, from about 110 °C to about 182 °C, from about 96 °C to about 180 °C, e.g., about 145 °C. The spray drying is generally conducted with an outlet temperature of from about 30 °C to about 90 °C, for example from about 40 °C to about 80 °C, about 45 °C to about 80 °C e.g., about 75 °C. The atomization flow rate is generally from about 4 kg h to about 12 kg/h, for example, from about 4.3 kg/h to about 10.5 kg h, e.g., about 6 kg/h or about 10.5 kg/h. The feed flow rate is generally from about 3 kg/h to about 10 kg/h, for example, from about 3.5 kg/h to about 9.0 kg/h, e.g., about 8 kg/h or about 7.1 kg/h. The atomization ratio is generally from about 0.3 to 1.7, e.g., from about 0.5 to 1.5, e.g., about 0.8 or about 1.5.
Removal of the solvent may require a subsequent drying step, such as tray drying, fluid bed drying (e.g., from about room temperature to about 100 °C), vacuum drying, microwave drying, rotary drum drying or biconical vacuum drying (e.g., from about room temperature to about 200 °C).
Synthesis of Compound 1
Acid Chloride Moiety
Synthesis of (2,2-difluoro-l,3-benzodioxol-5-yl)-l-ethylacetate-acetonitrile
ouene, 2 , CN
A reactor was purged with nitrogen and charged with 900 mL of toluene. The solvent was degassed via nitrogen sparge for no less than 16 h. To the reactor was then charged Na3P04 (155.7 g, 949.5 mmol), followed by bis(dibenzylideneacetone) palladium (0) (7.28 g, 12.66 mmol). A 10% w/w solution of tert-butylphosphine in hexanes (51.23 g, 25.32 mmol) was charged over 10 min at 23 °C from a nitrogen purged addition funnel. The mixture was allowed to stir for 50 min, at which time 5-bromo-2,2-difluoro-l,3-benzodioxole (75 g, 316.5 mmol) was added over 1 min. After stirring for an additional 50 min, the mixture was charged with ethyl cyanoacetate (71.6 g, 633.0 mmol) over 5 min followed by water (4.5 mL) in one portion. The mixture was heated to 70 °C over 40 min and analyzed by HPLC every 1 – 2 h for the percent conversion of the reactant to the product. After complete conversion was observed (typically 100% conversion after 5 – 8 h), the mixture was cooled to 20 – 25 °C and filtered through a celite pad. The celite pad was rinsed with toluene (2 X 450 mL) and the combined organics were concentrated to 300 mL under vacuum at 60 – 65 °C. The concentrate was charged with 225mL DMSO and concentrated under vacuum at 70 – 80 °C until active distillation of the solvent ceased. The solution was cooled to 20 – 25 °C and diluted to 900 mL with DMSO in preparation for Step 2. Ή NMR (500 MHz, CDC13) δ 7.16 – 7.10 (m, 2H), 7.03 (d, J = 8.2 Hz, 1H), 4.63 (s, 1H), 4.19 (m, 2H), 1.23 (t, J= 7.1 Hz, 3H).
Synthesis of (2,2-difluoro-l^-benzodioxol-5-yl)-acetonitrile.
[00311] The DMSO solution of (2,2-difluoro-l,3-benzodioxol-5-yl)-l-ethylacetate-acetonitrile from above was charged with 3 N HCl (617.3 mL, 1.85 mol) over 20 min while maintaining an internal temperature < 40 °C. The mixture was then heated to 75°C over 1 h and analyzed by HPLC every 1 – 2 h for % conversion. When a conversion of > 99% was observed (typically after 5 – 6 h), the reaction was cooled to 20 – 25 °C and extracted with MTBE (2 X 525 mL), with sufficient time to allow for complete phase separation during the extractions. The combined organic extracts were washed with 5% NaCl (2 X 375 mL). The solution was then transferred to equipment appropriate for a 1.5 – 2.5 Torr vacuum distillation that was equipped with a cooled receiver flask. The solution was concentrated under vacuum at < 60°C to remove the solvents. (2,2-Difluoro-l,3-benzodioxol-5-yl)-acetonitrile was then distilled from the resulting oil at 125 – 130 °C (oven temperature) and 1.5 – 2.0 Torr. (2,2-Difluoro-l,3- benzodioxol-5-yl)-acetonitrile was isolated as a clear oil in 66% yield from 5-bromo-2,2- difluoro-l,3-benzodioxole (2 steps) and with an HPLC purity of 91.5% AUC (corresponds to a w/w assay of 95%). Ή NMR (500 MHz, DMSO) 6 7.44 (br s, 1H), 7.43 (d, J= 8.4 Hz, 1H), 7.22 (dd, J= 8.2, 1.8 Hz, 1H), 4.07 (s, 2H). Synthesis of (2,2-difluoro- l,3-benzodioxol-5-yl)-cycIopropanecarbonitrUe.
MTBE
A stock solution of 50% w/w NaOH was degassed via nitrogen sparge for no less than 16 h. An appropriate amount of MTBE was similarly degassed for several hours. To a reactor purged with nitrogen was charged degassed MTBE (143 mL) followed by (2,2-difluoro-l,3- benzodioxol-5-yl)-acetonitrile (40.95 g, 207.7 mmol) and tetrabutylammonium bromide (2.25 g, 10.38 mmol). The volume of the mixture was noted and the mixture was degassed via nitrogen sparge for 30 min. Enough degassed MTBE is charged to return the mixture to the original volume prior to degassing. To the stirring mixture at 23.0 °C was charged degassed 50% w/w NaOH (143 mL) over 10 min followed by l-bromo-2-chloroethane (44.7 g, 311.6 mmol) over 30 min. The reaction was analyzed by HPLC in 1 h intervals for % conversion. Before sampling, stirring was stopped and the phases allowed to separate. The top organic phase was sampled for analysis. When a % conversion > 99 % was observed (typically after 2.5 – 3 h), the reaction mixture was cooled to 10 °C and was charged with water (461 mL) at such a rate as to maintain a temperature < 25 °C. The temperature was adjusted to 20 – 25 °C and the phases separated. Note: sufficient time should be allowed for complete phase separation. The aqueous phase was extracted with MTBE (123 mL), and the combined organic phase was washed with 1 N HC1 (163mL) and 5% NaCl (163 mL). The solution of (2,2-difluoro- 1,3 -benzodioxol-5-yl)- cyclopropanecarbonitrile in MTBE was concentrated to 164 mL under vacuum at 40 – 50 °C. The solution was charged with ethanol (256 mL) and again concentrated to 164 mL under vacuum at 50 – 60 °C. Ethanol (256 mL) was charged and the mixture concentrated to 164 mL under vacuum at 50 – 60 °C. The resulting mixture was cooled to 20 – 25 °C and diluted with ethanol to 266 mL in preparation for the next step. lH NMR (500 MHz, DMSO) 6 7.43 (d, J= 8.4 Hz, 1H), 7.40 (d, J= 1.9 Hz, 1H), 7.30 (dd, J= 8.4, 1.9 Hz, 1H), 1.75 (m, 2H), 1.53 (m, 2H). [00314] Synthesis of l-(2,2-difluoro-l,3-benzodioxol-5-yl)-cyclopropanecarboxylic acid.
The solution of (2,2-difluoro-l ,3-benzodioxol-5-yl)-cyclopropanecarbonitrile in ethanol from the previous step was charged with 6 N NaOH (277 mL) over 20 min and heated to an internal temperature of 77 – 78 °C over 45 min. The reaction progress was monitored by HPLC after 16 h. Note: the consumption of both (2,2-difluoro-l,3-benzodioxol-5-yl)- cyclopropanecarbonitrile and the primary amide resulting from partial hydrolysis of (2,2-difluoro- l,3-benzodioxol-5-yl)-cyclopropanecarbonitrile were monitored. When a % conversion > 99 % was observed (typically 100% conversion after 16 h), the reaction mixture was cooled to 25 °C and charged with ethanol (41 mL) and DCM (164 mL). The solution was cooled to 10 °C and charged with 6 N HC1 (290 mL) at such a rate as to maintain a temperature < 25 °C. After warming to 20 – 25 °C, the phases were allowed to separate. The bottom organic phase was collected and the top aqueous phase was back extracted with DCM (164 mL). Note: the aqueous phase was somewhat cloudy before and after the extraction due to a high concentration of inorganic salts. The organics were combined and concentrated under vacuum to 164 mL. Toluene (328 mL) was charged and the mixture condensed to 164 mL at 70 – 75 °C. The mixture was cooled to 45 °C, charged with MTBE (364 mL) and stirred at 60 °C for 20 min. The solution was cooled to 25 °C and polish filtered to remove residual inorganic salts. MTBE (123 mL) was used to rinse the reactor and the collected solids. The combined organics were transferred to a clean reactor in preparation for the next step.
Isolation of l-(2,2-difluoro-l,3-benzodioxol-5-yl)-cyclopropanecar boxy lie acid.
The solution of l-(2,2-difluoro- 1 ,3-benzodioxol-5-yl)-cyclopropanecarboxylic acid from the previous step is concentrated under vacuum to 164 mL, charged with toluene (328 mL) and concentrated to 164 mL at 70 – 75 °C. The mixture was then heated to 100 – 105 °C to give a homogeneous solution. After stirring at that temperature for 30 min, the solution was cooled to 5 °C over 2 hours and maintained at 5 °C for 3 hours. The mixture was then filtered and the reactor and collected solid washed with cold 1 :1 toluene/n-heptane (2 X 123 mL). The material was dried under vacuum at 55 °C for 17 hours to provide l-(2,2-difluoro-l,3-benzodioxol-5-yl)- cyclopropanecarboxylic acid as an off-white crystalline solid. l-(2,2-difluoro-l,3-benzodioxol- 5-yl)-cyclopropanecarboxylic acid was isolated in 79% yield from (2,2-difluoro-l,3- benzodioxol-5-yl)-acetonitrile (3 steps including isolation) and with an HPLC purity of 99.0% AUC. ESI-MS m/z calc. 242.04, found 241.58 (M+l)+; Ή NMR (500 MHz, DMSO) δ 12.40 (s, 1H), 7.40 (d, J= 1.6 Hz, 1H), 7.30 (d, J= 8.3 Hz, 1H), 7.17 (dd, J= 8.3, 1.7 Hz, 1H), 1.46 (m, 2H), 1.17 (m, 2H).
Alternative Synthesis of the Acid Chloride Moiety [00319] Synthesis of (2,2-ditluoro-l,3-benzodioxol-5-yl)-methanol.
1. Vitride (2 equiv)
PhCH3 (10 vol)
[00320] Commercially available 2,2-difluoro-l,3-benzodioxole-5-carboxylic acid (1.0 eq) is slurried in toluene (10 vol). Vitride® (2 eq) is added via addition funnel at a rate to maintain the temperature at 15-25 °C. At the end of addition the temperature is increased to 40 °C for 2 h then 10% (w/w) aq. NaOH (4.0 eq) is carefully added via addition funnel maintaining the temperature at 40-50 °C. After stirring for an additional 30 minutes, the layers are allowed to separate at 40 °C. The organic phase is cooled to 20 °C then washed with water (2 x 1.5 vol), dried (Na2SO4), filtered, and concentrated to afford crude (2,2-difluoro-l,3-benzodioxol-5-yl)-methanol that is used directly in the next step.
Synthesis of 5-chloromethyl-2,2-difluoro-l,3-benzodioxole.
1. SOCl2 (1.5 equiv)
DMAP (0.01 equiv)
(2,2-difluoro- 1 ,3-benzodioxol-5-yl)-methanol ( 1.0 eq) is dissolved in MTBE (5 vol). A catalytic amount of DMAP (1 mol %) is added and S0C12 (1.2 eq) is added via addition funnel. The S0C12 is added at a rate to maintain the temperature in the reactor at 15-25 °C. The temperature is increased to 30 °C for 1 hour then cooled to 20 °C then water (4 vol) is added via addition funnel maintaining the temperature at less than 30 °C. After stirring for an additional 30 minutes, the layers are allowed to separate. The organic layer is stirred and 10% (w/v) aq. NaOH (4.4 vol) is added. After stirring for 15 to 20 minutes, the layers are allowed to separate. The organic phase is then dried (Na2SO_ , filtered, and concentrated to afford crude 5-chloromethyl- 2,2-difluoro-l,3-benzodioxole that is used directly in the next step.
Synthesis of (2,2-difluoro-l,3-benzodioxol-5-yl)-acetonitrile.
A solution of 5-chloromethyl-2,2-difluoro- 1 ,3-benzodioxole ( 1 eq) in DMSO ( 1.25 vol) is added to a slurry of NaCN (1.4 eq) in DMSO (3 vol) maintaining the temperature between 30-40 °C. The mixture is stirred for 1 hour then water (6 vol) is added followed by MTBE (4 vol). After stirring for 30 min, the layers are separated. The aqueous layer is extracted with MTBE (1.8 vol). The combined organic layers are washed with water (1,8 vol), dried (Na2S04), filtered, and concentrated to afford crude (2,2-difluoro-l,3-benzodioxol-5-yl)-acetonitrile (95%) that is used directly in the next step.
The remaining steps are the same as described above for the synthesis of the acid moiety.
Amine Moiety
Synthesis of 2-bromo-5-fluoro-4-ntroaniline.
Synthesis of benzyIglycoIated-4-ammonium-2-bromo-5-fluoroaniline tosylate salt.
1) l ^OBn
cat. Zn(C104)2-2H20 ®
DCM
A thoroughly dried flask under N2 was charged with the following: Activated powdered 4A molecular sieves (50 wt% based on 2-bromo-5-fluoro-4-nitroaniline), 2-Bromo-5- fluoro-4-nitroaniline (1.0 equiv), zinc perchlorate dihydrate (20 mol%), and toluene (8 vol). The mixture was stirred at room temperature for NMT 30 min. Lastly, (R)-benzyl glycidyl ether (2.0 equiv) in toluene (2 vol) was added in a steady stream. The reaction was heated to 80 °C (internal temperature) and stirred for approximately 7 hours or until 2-Bromo-5-fluoro-4-nitroaniline was <5%AUC.
The reaction was cooled to room temperature and Celite (50 wt%) was added, followed by ethyl acetate (10 vol). The resulting mixture was filtered to remove Celite and sieves and washed with ethyl acetate (2 vol). The filtrate was washed with ammonium chloride solution (4 vol, 20% w/v). The organic layer was washed with sodium bicarbonate solution (4 vol x 2.5% w/v). The organic layer was concentrated in vacuo on a rotovap. The resulting slurry was dissolved in isopropyl acetate (10 vol) and this solution was transferred to a Buchi hydrogenator.
The hydrogenator was charged with 5wt% Pt(S)/C (1.5 mol%) and the mixture was stirred under N2 at 30 °C (internal temperature). The reaction was flushed with N2 followed by hydrogen. The hydrogenator pressure was adjusted to 1 Bar of hydrogen and the mixture was stirred rapidly (>1200 rpm). At the end of the reaction, the catalyst was filtered through a pad of Celite and washed with dichloromethane (10 vol). The filtrate was concentrated in vacuo. Any remaining isopropyl acetate was chased with dichloromethane (2 vol) and concentrated on a rotavap to dryness.
The resulting residue was dissolved in dichloromethane (10 vol). jP-Toluenesulfonic acid monohydrate (1.2 equiv) was added and stirred overnight. The product was filtered and washed with dichloromethane (2 vol) and suction dried. The wetcake was transferred to drying trays and into a vacuum oven and dried at 45 °C with N2 bleed until constant weight was achieved. Benzylglycolated-4-ammonium-2-bromo-5-fluoroaniline tosylate salt was isolated as an off-white solid.
Chiral purity was determined to be >97%ee.
[00334] Synthesis of (3-Chloro-3-methylbut-l-ynyl)trimethylsilane.
[00335] Propargyl alcohol (1.0 equiv) was charged to a vessel. Aqueous hydrochloric acid (37%, 3.75 vol) was added and stirring begun. During dissolution of the solid alcohol, a modest endotherm (5-6 °C) is observed. The resulting mixture was stirred overnight (16 h), slowly becoming dark red. A 30 L jacketed vessel is charged with water (5 vol) which is then cooled to 10 °C. The reaction mixture is transferred slowly into the water by vacuum, maintaining the internal temperature of the mixture below 25 °C. Hexanes (3 vol) is added and the resulting mixture is stirred for 0.5 h. The phases were settled and the aqueous phase (pH < 1) was drained off and discarded. The organic phase was concentrated in vacuo using a rotary evaporator, furnishing the product as red oil. [00336] Synthesis of (4-(Benzyloxy)-3,3-dimethylbut-l-yttyl)trimethylsiIane.
[00337] Method A
[00338] All equivalent and volume descriptors in this part are based on a 250g reaction.
Magnesium turnings (69.5 g, 2.86 mol, 2.0 equiv) were charged to a 3 L 4-neck reactor and stirred with a magnetic stirrer under nitrogen for 0.5 h. The reactor was immersed in an ice- water bath. A solution of the propargyl chloride (250 g, 1.43 mol, 1.0 equiv) in THF (1.8 L, 7.2 vol) was added slowly to the reactor, with stirring, until an initial exotherm (-10 °C) was observed. The Grignard reagent formation was confirmed by IPC usingΉ-NMR spectroscopy. Once the exotherm subsided, the remainder of the solution was added slowly, maintaining the batch temperature <15 °C. The addition required ~3.5 h. The resulting dark green mixture was decanted into a 2 L capped bottle.
[00339] All equivalent and volume descriptors in this part are based on a 500g reaction. A 22 L reactor was charged with a solution of benzyl chloromethyl ether (95%, 375 g, 2.31 mol, 0.8 equiv) in THF (1.5 L, 3 vol). The reactor was cooled in an ice-water bath. Two Grignard reagent batches prepared as described above were combined and then added slowly to the benzyl chloromethyl ether solution via an addition funnel, maintaining the batch temperature below 25 °C. The addition required 1.5 h. The reaction mixture was stirred overnight (16 h).
[00340] All equivalent and volume descriptors in this part are based on a 1 kg reaction. A solution of 15%» ammonium chloride was prepared in a 30 L jacketed reactor (1.5 kg in 8.5 kg of water, 10 vol). The solution was cooled to 5 °C. Two Grignard reaction mixtures prepared as described above were combined and then transferred into the ammonium chloride solution via a header vessel. An exotherm was observed in this quench, which was carried out at a rate such as to keep the internal temperature below 25 °C. Once the transfer was complete, the vessel jacket temperature was set to 25 °C. Hexanes (8 L, 8 vol) was added and the mixture was stirred for 0.5 h. After settling the phases, the aqueous phase (pH 9) was drained off and discarded. The remaining organic phase was washed with water (2 L, 2 vol). The organic phase was concentrated in vacuo using a 22 L rotary evaporator, providing the crude product as an orange oil.
[00341] Method B
[00342] Magnesium turnings (106 g, 4.35 mol, 1.0 eq) were charged to a 22 L reactor and then suspended in THF (760 mL, 1 vol). The vessel was cooled in an ice-water bath such that the batch temperature reached 2 °C. A solution of the propargyl chloride (760 g, 4.35 mol, 1.0 equiv) in THF (4.5 L, 6 vol) was added slowly to the reactor. After 100 mL was added, the addition was stopped and the mixture stirred until a 13 °C exotherm was observed, indicating the Grignard reagent initiation. Once the exotherm subsided, another 500 mL of the propargyl chloride solution was added slowly, maintaining the batch temperature <20 °C. The Grignard reagent formation was confirmed by IPC using Ή-NMR spectroscopy. The remainder of the propargyl chloride solution was added slowly, maintaining the batch temperature <20 °C. The addition required -1.5 h. The resulting dark green solution was stirred for 0.5 h. The Grignard reagent formation was confirmed by IPC using Ή-NMR spectroscopy. Neat benzyl
chloromethyl ether was charged to the reactor addition funnel and then added dropwise into the reactor, maintaining the batch temperature below 25 °C. The addition required 1.0 h. The reaction mixture was stirred overnight. The aqueous work-up and concentration was carried out using the same procedure and relative amounts of materials as in Method A to give the product as an orange oil.
[00343] Syntheisis of 4-Benzyloxy-3,3-dimethylbut-l-yne.
2 steps
[00344] A 30 L jacketed reactor was charged with methanol (6 vol) which was then cooled to 5 °C. Potassium hydroxide (85%, 1.3 equiv) was added to the reactor. A 15-20 °C exotherm was observed as the potassium hydroxide dissolved. The jacket temperature was set to 25 °C. A solution of 4-benzyloxy-3,3-dimethyl-l-trimethylsilylbut-l-yne (1.0 equiv) in methanol (2 vol) was added and the resulting mixture was stirred until reaction completion, as monitored by HPLC. Typical reaction time at 25 °C is 3-4 h. The reaction mixture is diluted with water (8 vol) and then stirred for 0.5 h. Hexanes (6 vol) was added and the resulting mixture was stirred for 0.5 h. The phases were allowed to settle and then the aqueous phase (pH 10-11) was drained off and discarded. The organic phase was washed with a solution of KOH (85%, 0.4 equiv) in water (8 vol) followed by water (8 vol). The organic phase was then concentrated down using a rotary evaporator, yielding the title material as a yellow-orange oil. Typical purity of this material is in the 80% range with primarily a single impurity present. Ή NMR (400 MHz, C6D6) δ 7.28 (d, 2 H, J = 7.4 Hz), 7.18 (t, 2 H, J= 7.2 Hz), 7.10 (d, 1H, J= 7.2 Hz), 4.35 (s, 2 H), 3.24 (s, 2 H), 1.91 (s, 1 H), 1.25 (s, 6 H).
[00345] Synthesis of N-benzylglycolated-5-amino-2-(2-benzyloxy-l,l-dimethylethyl)-6- fluoroindole.
[00346] Method A
[00347] Synthesis of Benzylglycolated 4-Amino-2-(4-benzyloxy-3,3-dimethyIbut- l-ynyl)-5- fluoroaniline.
[00348] Benzylglycolated 4-ammonium-2-bromo-5-flouroaniline tosylate salt was freebased by stirring the solid in EtOAc (5 vol) and saturated NaHCC>3 solution (5 vol) until clear organic layer was achieved. The resulting layers were separated and the organic layer was washed with saturated NaHC03 solution (5 vol) followed by brine and concentrated in vacuo to obtain benzylglocolated 4-ammonium-2-bromo-5-flouroaniline tosylate salt as an oil.
[00349] Then, a flask was charged with benzylglycolated 4-ammonium-2-bromo-5- flouroaniline tosylate salt (freebase, 1.0 equiv), Pd(OAc) (4.0 mol%), dppb (6.0 mol%) and powdered K2CO3 (3.0 equiv) and stirred with acetonitrile (6 vol) at room temperature. The resulting reaction mixture was degassed for approximately 30 min by bubbling in N2 with vent. Then 4-benzyloxy-3,3-dimethylbut-l-yne (1.1 equiv) dissolved in acetonitrile (2 vol) was added in a fast stream and heated to 80 °C and stirred until complete consumption of 4-ammonium-2- bromo-5-flouroaniline tosylate salt was achieved. The reaction slurry was cooled to room temperature and filtered through a pad of Celite and washed with acetonitrile (2 vol). Filtrate was concentrated in vacuo and the residue was redissolved in EtOAc (6 vol). The organic layer was washed twice with NH4CI solution (20% w/v, 4 vol) and brine (6 vol). The resulting organic layer was concentrated to yield brown oil and used as is in the next reaction.
[00350] Synthesis of N-benzylglycolated-5-amino-2-(2-benzyloxy-l,l-dimethylethyl)-6- fluoroindole.
[00351] Crude oil of benzylglycolated 4-amino-2-(4-benzyloxy-3,3-dimethylbut-l-ynyl)-5- fluoroaniline was dissolved in acetonitrile (6 vol) and added (MeCN)2PdCl2 (15 mol%) at room temperature. The resulting mixture was degassed using N2 with vent for approximately 30 min. Then the reaction mixture was stirred at 80 °C under N2 blanket overnight. The reaction mixture was cooled to room temperature and filtered through a pad of Celite and washed the cake with acetonitrile (1 vol). The resulting filtrate was concentrated in vacuo and redissolved in EtOAc (5 vol). Deloxane-II THP (5 wt% based on the theoretical yield of N-benzylglycolated-5-amino-2- (2-benzyloxy-l,l-dimethylethyl)-6-fluoroindole) was added and stirred at room temperature overnight. The mixture was then filtered through a pad of silica (2.5 inch depth, 6 inch diameter filter) and washed with EtOAc (4 vol). The filtrate was concentrated down to a dark brown residue, and used as is in the next reaction.
[00352] Repurification of crude N-benzylglycolated-5-amino-2-(2-benzyloxy- 1,1- dimethylethyl)-6-fluoroindole:
[00353] The crude N-benzylglycolated-5-amino-2-(2-benzyloxy- 1 , l-dimethylethyl)-6- fluoroindole was dissolved in dichloromethane (~1.5 vol) and filtered through a pad of silica initially using 30% EtOAc/heptane where impurities were discarded. Then the silica pad was washed with 50% EtO Ac/heptane to isolate N-benzylglycolated-5-amino-2-(2-benzyloxy-l,l- dimethylethyl)-6-fluoroindole until faint color was observed in the filtrate. This filtrate was concentrated in vacuo to afford brown oil which crystallized on standing at room temperature. Ή NMR (400 MHz, DMSO) 6 7.38-7.34 (m, 4 H), 7.32-7.23 (m, 6 H), 7.21 (d, 1 H, J= 12.8 Hz), 6.77 (d, 1H, J= 9.0 Hz), 6.06 (s, 1 H), 5.13 (d, 1H, J = 4.9 Hz), 4.54 (s, 2 H), 4.46 (br. s, 2 H), 4.45 (s, 2 H), 4.33 (d, 1 H, J= 12.4 Hz), 4.09-4.04 (m, 2 H), 3.63 (d, 1H, J= 9.2 Hz), 3.56 (d, 1H, J= 9.2 Hz), 3.49 (dd, 1H, J= 9.8, 4.4 Hz), 3.43 (dd, 1H, J= 9.8, 5.7 Hz), 1.40 (s, 6 H).
[00354] Synthesis of N-benzyIglycolated-5-amino-2-(2-benzyIoxy-l,l-diniethylethyl)-6- fluoroindole.
[00355] Method B
2. (MeCN)2PdCl2
MeCN, 80 <€
3. Silica gel filtration
[00356] Palladium acetate (33 g, 0.04 eq), dppb (94 g, 0.06 eq), and potassium carbonate (1.5 kg, 3.0 eq) are charged to a reactor. The free based oil benzylglocolated 4-ammonium-2-bromo- 5-flouroaniline (1.5 kg, 1.0 eq) was dissolved in acetonitrile (8.2 L, 4.1 vol) and then added to the reactor. The mixture was sparged with nitrogen gas for NLT 1 h. A solution of 4-benzyloxy- 3,3-dimethylbut-l-yne (70%), 1.1 kg, 1.05 eq) in acetonitrile was added to the mixture which was then sparged with nitrogen gas for NLT 1 h. The mixture was heated to 80 °C and then stirred overnight. IPC by HPLC is carried out and the reaction is determined to be complete after 16 h. The mixture was cooled to ambient temperature and then filtered through a pad of Celite (228 g). The reactor and Celite pad were washed with acetonitrile (2 x 2 L, 2 vol). The combined phases are concentrated on a 22 L rotary evaporator until 8 L of solvent have been collected, leaving the crude product in 7 L (3.5 vol) of acetonitrile. [00357] 5 s-acetonitriledichloropalladium ( 144 g, 0.15 eq) was charged to the reactor. The crude solution was transferred back into the reactor and the roto-vap bulb was washed with acetonitrile (4 L, 2 vol). The combined solutions were sparged with nitrogen gas for NLT 1 h. The reaction mixture was heated to 80 °C for NLT 16 h. In process control by HPLC shows complete consumption of starting material. The reaction mixture was filtered through Celite (300 g). The reactor and filter cake were washed with acetonitrile (3 L, 1.5 vol). The combined filtrates were concentrated to an oil by rotary evaporation. The oil was dissolved in ethyl acetate (8.8 L, 4.4 vol). The solution was washed with 20% ammonium chloride (5 L, 2.5 vol) followed by 5% brine (5 L, 2.5 vol). Silica gel (3.5 kg, 1.8 wt. eq.) of silica gel was added to the organic phase, which was stirred overnight. Deloxan THP II metal scavenger (358 g) and heptane (17.6 L) were added and the resulting mixture was stirred for NLT 3 h. The mixture was filtered through a sintered glass funnel. The filter cake was washed with 30% ethyl acetate in heptane (25 L). The combined filtrates were concentrated under reduced pressure to give N- benzylglycolated-5-amino-2-(2-benzyloxy-l,l-dimethylethyl)-6-fluoroindole as a brown paste ( 1.4 kgl.Svnthesis of Compound 1
[00358] Synthesis of benzyl protected Compound 1.
SOCI2 were distilled off using rotavop. Additional toluene (2.5 vol, based on l-(2,2-difluoro- l,3-benzodioxol-5-yl)-cyclopropanecarboxylic acid) was added and distilled again. The crude acid chloride was dissolved in dichloromethane (2 vol) and added via addition funnel to a mixture of N-benzylglycolated-5-amino-2-(2-benzyloxy-l,l-dimethylethyl)-6-fluoroindole (1.0 equiv), and triethylamine (2.0 equiv) in dichloromethane (7 vol) while maintaining 0-3 °C (internal temperature). The resulting mixture was stirred at 0 °C for 4 hrs and then warmed to room temperature overnight. Distilled water (5 vol) was added to the reaction mixture and stirred for NLT 30 min and the layers were separated. The organic phase was washed with 20 wt% K2CO3 (4 vol x 2) followed by a brine wash (4 vol) and concentrated to afford crude benzyl protected Compound 1 as a thick brown oil, which was purified further using silica pad filtration.
[00360] Silica gel pad filtration: Crude benzyl protected Compound 1 was dissolved in ethyl acetate (3 vol) in the presence of activated carbon Darco-G (10wt%, based on theoretical yield of benzyl protected Compound 1) and stirred at room temperature overnight. To this mixture was added heptane (3 vol) and filtered through a pad of silica gel (2x weight of crude benzyl protected Compound 1). The silica pad was washed with ethyl acetate/heptane (1:1, 6 vol) or until little color was detected in the filtrate. The filtrate was concentrated in vacuo to afford benzyl protected Compound 1 as viscous reddish brown oil, and used directly in the next step.
[00361] Repurification: Benzyl protected Compound 1 was redissolved in dichloromethane (1 vol, based on theoretical yield of benzyl protected Compound 1) and loaded onto a silica gel pad (2x weight of crude benzyl protected Compound 1). The silica pad was washed with
dichloromethane (2 vol, based on theoretical yield of benzyl protected Compound 1) and the filtrate was discarded. The silica pad was washed with 30% ethyl acetate/heptane (5 vol) and the filtrate was concentrated in vacuo to afford benzyl protected Compound 1 as viscous reddish orange oil, and used directly in the next step. [00362] Synthesis of Compound 1.
OBn 4 steps
[00363] Method A
[00364] A 20 L autoclave was flushed three times with nitrogen gas and then charged with palladium on carbon (Evonik E 101 NN/W, 5% Pd, 60% wet, 200 g, 0.075 mol, 0.04 equiv). The autoclave was then flushed with nitrogen three times. A solution of crude benzyl protected Compound 1 (1.3 kg, ~ 1.9 mol) in THF (8 L, 6 vol) was added to the autoclave via suction. The vessel was capped and then flushed three times with nitrogen gas. With gentle stirring, the vessel was flushed three times with hydrogen gas, evacuating to atmosphere by diluting with nitrogen. The autoclave was pressurized to 3 Bar with hydrogen and the agitation rate was increased to 800 rpm. Rapid hydrogen uptake was observed (dissolution). Once uptake subsided, the vessel was heated to 50 °C.
[00365] For safety purposes, the thermostat was shut off at the end of every work-day. The vessel was pressurized to 4 Bar with hydrogen and then isolated from the hydrogen tank.
[00366] After 2 full days of reaction, more Pd / C (60 g, 0.023 mol, 0.01 equiv) was added to the mixture. This was done by flushing three times with nitrogen gas and then adding the catalyst through the solids addition port. Resuming the reaction was done as before. After 4 full days, the reaction was deemed complete by HPLC by the disappearance of not only the starting material but also of the peak corresponding to a mono-benzylated intermediate. [00367] The reaction mixture was filtered through a Celite pad. The vessel and filter cake were washed with THF (2 L, 1.5 vol). The Celite pad was then wetted with water and the cake discarded appropriately. The combined filtrate and THF wash were concentrated using a rotary evaporator yielding the crude product as a black oil, 1 kg.
[00368] The equivalents and volumes in the following purification are based on 1 kg of crude material. The crude black oil was dissolved in 1 :1 ethyl acetate-heptane. The mixture was charged to a pad of silica gel (1.5 kg, 1.5 wt. equiv) in a fritted funnel that had been saturated with 1 :1 ethyl acetate-heptane. The silica pad was flushed first with 1 :1 ethyl acetate-heptane (6 L, 6 vol) and then with pure ethyl acetate (14 L, 14 vol). The eluent was collected in 4 fractions which were analyzed by HPLC.
[00369] The equivalents and volumes in the following purification are based on 0.6 kg of crude material. Fraction 3 was concentrated by rotary evaporation to give a brown foam (600 g) and then redissolved in MTBE (1.8 L, 3 vol). The dark brown solution was stirred overnight at ambient temperature, during which time, crystallization occurred. Heptane (55 mL, 0.1 vol) was added and the mixture was stirred overnight. The mixture was filtered using a Buchner funnel and the filter cake was washed with 3:1 MTBE-heptane (900 mL, 1.5 vol). The filter cake was air-dried for 1 h and then vacuum dried at ambient temperature for 16 h, furnishing 253 g of Compound 1 as an off-white solid.
[00370] The equivalents and volumes for the following purification are based on 1.4 kg of crude material. Fractions 2 and 3 from the above silica gel filtration as well as material from a previous reaction were combined and concentrated to give 1.4 kg of a black oil. The mixture was resubmitted to the silica gel filtration (1.5 kg of silica gel, eluted with 3.5 L, 2.3 vol of 1 :1 ethyl acetate-heptane then 9 L, 6 vol of pure ethyl acetate) described above, which upon concentration gave a tan foamy solid (390 g).
[00371] The equivalents and volumes for the following purification are based on 390 g of crude material. The tan solid was insoluble in MTBE, so was dissolved in methanol (1.2 L, 3 vol). Using a 4 L Morton reactor equipped with a long-path distillation head, the mixture was distilled down to 2 vol. MTBE (1.2 L, 3 vol) was added and the mixture was distilled back down to 2 vol. A second portion of MTBE (1.6 L, 4 vol) was added and the mixture was distilled back down to 2 vol. A third portion of MTBE (1.2 L, 3 vol) was added and the mixture was distilled back down to 3 vol. Analysis of the distillate by GC revealed it to consist of -6% methanol. The thermostat was set to 48 °C (below the boiling temp of the MTBE-methanol azeotrope, which is 52 °C). The mixture was cooled to 20 °C over 2 h, during which time a relatively fast crystallization occurred. After stirring the mixture for 2 h, heptane (20 mL, 0.05 vol) was added and the mixture was stirred overnight (16 h). The mixture was filtered using a Buchner funnel and the filter cake was washed with 3:1 MTBE-heptane (800 mL, 2 vol). The filter cake was air- dried for 1 h and then vacuum dried at ambient temperature for 16 h, furnishing 130 g of Compound 1 as an off-white solid.
[00372] Method B
[00373] Benzyl protected Compound 1 was dissolved in THF (3 vol) and then stripped to dryness to remove any residual solvent. Benzyl protected Compound 1 was redissolved in THF (4 vol) and added to the hydrogenator containing 5 wt% Pd/C (2.5 mol%, 60% wet, Degussa E5 El 01 N /W). The internal temperature of the reaction was adjusted to 50 °C, and flushed with N2 (x5) followed by hydrogen (x3). The hydrogenator pressure was adjusted to 3 Bar of hydrogen and the mixture was stirred rapidly (>1100 rpm). At the end of the reaction, the catalyst was filtered through a pad of Celite and washed with THF (1 vol). The filtrate was concentrated in vacuo to obtain a brown foamy residue. The resulting residue was dissolved in MTBE (5 vol) and 0.5N HC1 solution (2 vol) and distilled water (1 vol) were added. The mixture was stirred for NLT 30 min and the resulting layers were separated. The organic phase was washed with 10wt% K2CO3 solution (2 vol x2) followed by a brine wash. The organic layer was added to a flask containing silica gel (25 wt%), Deloxan-THP II (5wt%, 75% wet), and
Na2S04 and stirred overnight. The resulting mixture was filtered through a pad of Celite and washed with 10%THF/MTBE (3 vol). The filtrate was concentrated in vacuo to afford crude Compound 1 as pale tan foam.
[00374] Compound 1 recovery from the mother liquor: Option A.
[00375] Silica gel pad filtration: The mother liquor was concentrated in vacuo to obtain a brown foam, dissolved in dichloromethane (2 vol), and filtered through a pad of silica (3x weight of the crude Compound 1). The silica pad was washed with ethyl acetate/heptane (1 :1, 13 vol) and the filtrate was discarded. The silica pad was washed with 10% THF/ethyl acetate (10 vol) and the filtrate was coiicentraied in vacuo to afford Compound 1 as pale tan foam. The above crystallization procedure was followed to isolate the remaining Compound 1.
{00376] Compound 1 recovery from the mother liquor: Option B,
[00377] Silica gel column chromatography: After chromatography on silica gel (50% ethyl acetate/hexaties to 100% ethyl acetate), the desired compound was isolated as pale tan foam. The above crystallization procedure was followed to isolate the remaining Compound 1.
{003781 Additional Recrystaliization of Compound 1
[ 0379‘j Solid Compound 1 (135 kg) was suspended in IPA (5.4 L, 4 vol) and then heated to 82 °C. Upon complete dissolution (visual), heptane (540 mL, 0.4 vol) was added slowly. The mixture was cooled to 58 °C The mixture was then cooled slowly to 51 °C, during which time crystallization occurs. The heat source was shut down and the recrystalfeation mixture was allowed to cool naturally overnight. The mixture was filtered using a benchtop Buclmer funnel and the filter cake was washed with IPA (2.7 L, 2 vol). The filler cake was dried in the tunnel under air flow for 8 h and then was oven-dried in vacuo at 45-50 °C overnight to give 1.02 kg of recrystallized Compound 1 ,
100380] Compound 1 may also be prepared by one of several synthetic routes disclosed in US published patent application U S20090131 92, incorporated herein by reference.
{003811 Table 6 below recites analytical data for Compound 1.
Table 6.
[00384] 9.95g of Hydroxypropylmethylcellulose acetate succinate HG grade (HPMCAS-HG) was weighed into a 500 ml beaker, along with 50 mg of sodium lauryl sulfate (SLS). MeOH (200 ml) was mixed with the solid. The material was allowed to stir for 4 h. To insure maximum dissolution, after 2 h of stirring the solution was sonicated for 5 mins, then allowed to continue stirring for the remaining 2 h. A very fin suspension of HPMCAS remained in solution. However, visual observation determined that no gummy portions remained on the walls of the vessel or stuck to the bottom after tilting the vessel.
[00385] Compound 1 (1 Og) was poured into the 500 ml beaker, and the system was allowed to continue stirring. The solution was spray dried using the following parameters:
Formulation Description: Compound 1 Form A/HPMCAS/SLS (50/49.5/0.5)
Buchi Mini Spray Dryer
T inlet (setpoint) 145 °C
T outlet (start) 75 °C
T outlet (end) 55 °C
Nitrogen Pressure 75 psi
Aspirator 100 %
Pump 35 %
Rotometer 40 mm
Filter Pressure 65 mbar
Condenser Temp -3 °C
Run Time l h
1: Veit G, Avramescu RG, Perdomo D, Phuan PW, Bagdany M, Apaja PM, Borot F, Szollosi D, Wu YS, Finkbeiner WE, Hegedus T, Verkman AS, Lukacs GL. Some gating potentiators, including VX-770, diminish ΔF508-CFTR functional expression. Sci Transl Med. 2014 Jul 23;6(246):246ra97. doi: 10.1126/scitranslmed.3008889. PubMed PMID: 25101887.
2: Pettit RS, Fellner C. CFTR Modulators for the Treatment of Cystic Fibrosis. P T. 2014 Jul;39(7):500-11. PubMed PMID: 25083129; PubMed Central PMCID: PMC4103577.
3: Norman P. Novel picolinamide-based cystic fibrosis transmembrane regulator modulators: evaluation of WO2013038373, WO2013038376, WO2013038381, WO2013038386 and WO2013038390. Expert Opin Ther Pat. 2014 Jul;24(7):829-37. doi: 10.1517/13543776.2014.876412. Epub 2014 Jan 7. PubMed PMID: 24392786.
//////TEZACAFTOR, VX 661, PHASE 3, 1152311-62-0, UNII: 8RW88Y506K, deltaF508-CFTR corrector, Vertex, treatment of cystic fibrosis in patients homozygous to the F508del-CFTR mutation
CC(C)(CO)C1=CC2=CC(=C(C=C2N1CC(CO)O)F)NC(=O)C3(CC3)C4=CC5=C(C=C4)OC(O5)(F)F
CC(C)(CO)c1cc2cc(c(cc2n1C[C@H](CO)O)F)NC(=O)C3(CC3)c4ccc5c(c4)OC(O5)(F)F
| Febuxostat; 144060-53-7; Uloric; Adenuric; Tei 6720; 2-(3-cyano-4-isobutoxyphenyl)-4-methylthiazole-5-carboxylic acid; | |
| Molecular Formula: | C16H16N2O3S |
|---|---|
| Molecular Weight: | 316.37484 g/mol |
2-[3-cyano-4-(2-methylpropoxy)phenyl]-4-methyl-1,3-thiazole-5-carboxylic acid
Febuxostat is a thiazole derivative and inhibitor of XANTHINE OXIDASE that is used for the treatment of HYPERURICEMIA in patients with chronic GOUT.
CAS 144060-53-7
Febuxostat (INN; trade names Adenuric in Europe and New Zealand, Uloric in the US, Goturic in Latin America, Feburic in Japan) is a drug that inhibits xanthine oxidase, thus reducing production of uric acid in the body. It is used in the treatment of chronicgout and hyperuricemia.
Febuxostat was discovered by scientists at the Japanese pharmaceutical company Teijin in 1998. Teijin partnered the drug with TAP Pharmaceuticals in the US and Ipsen in Europe. Ipsen obtained marketing approval for febuxostat from the European Medicines Agency in April 2008, Takeda obtained FDA approval in February 2009, and Teijin obtained approval from the Japanese “Pharmaceuticals and Medical Devices Agency” in 2011.
Febuxostat is used to treat chronic gout and hyperuricemia.[2] National Institute for Health and Clinical Excellence concluded that febuxostat is more effective than standard doses of allopurinol, but not more effective than higher doses of allopurinol.[2]
Febuxostat is in the US pregnancy category C; there are no adequate and well-controlled studies in pregnant women.[3]
The adverse effects associated with febuxostat therapy include nausea, diarrhea, arthralgia, headache, increased hepatic serum enzyme levels and rash.[3][4]
Febuxostat is contraindicated with concomitant use of theophylline and chemotherapeutic agents, namely azathioprine and 6-mercaptopurine, because it could increase blood plasma concentrations of these drugs, and therefore their toxicity.[3][5]
Febuxostat is a non-purine-selective inhibitor of xanthine oxidase.[3] It works by non-competitively blocking the molybdenum pterincenter which is the active site on xanthine oxidase. Xanthine oxidase is needed to successively oxidize both hypoxanthine andxanthine to uric acid. Hence, febuxostat inhibits xanthine oxidase, therefore reducing production of uric acid. Febuxostat inhibits both oxidized as well as reduced form of xanthine oxidase because of which febuxostat cannot be easily displaced from the molybdenum pterin site.[4]

Febuxostat was discovered by scientists at the Japanese pharmaceutical company Teijin in 1998.[6] Teijin partnered the drug withTAP Pharmaceuticals in the US and Ipsen in Europe.[7][8][9]
Ipsen obtained marketing approval for febuxostat from the European Medicines Agency in April 2008,[10] Takeda obtained FDA approval in February 2009,[11][12] and Teijin obtained approval from the Japanese authorities in 2011.[13] Ipsen exclusively licensed its European rights to Menarini in 2009.[14] Teijin partnered with Astellas for distribution in China and southeast Asia.[15][16]
In the UK, NICE has found that febuxostat has a higher cost/benefit ratio than allopurinol and on that basis recommended febuxostat as a second-line drug for people who cannot use allopurinol.[2]
Febuxostat is marketed as Adenuric in Europe and New Zealand, Uloric in the US, Goturic and Goutex in Latin America, Feburic in Japan, and is generic in several countries and is available by many names in those countries.[1]
Febuxostat (Formula I) is an inhibitor of xanthine oxidase, which was discovered by the Japanese company Teijin Pharma Ltd and it is indicated for use in the treatment of hyperuricemia and chronic gout. Its chemical name is 2-(3-cyano-4-isobutoxyphenyl)-4-methyl- l,3-thiazole-5-carboxylic acid. It is marketed under the brand names Adenuric in Europe, Feburic in Japan and Uloric in USA and Canada.

In EP0513379B1 Febuxostat is prepared from 4-hydroxy-3-nitrobenzaldehyde, according to the following scheme.

This particular process suffers from major drawbacks. Not only it is very long, including seven steps from the starting material to the final product, but, most importantly, it employs the use of cyanides, which are extremely toxic reagents. Cyanide salts are likely to generate hydrocyanide, which sets a high amount of risk in an industrial scale process.
In Japanese patent JP06345724A(JP2706037B) the intermediate ethyl ester of Febuxostat is prepared from p-cyano-nitrobenzene, in three steps. Febuxostat may, then, be prepared by alkaline hydrolysis, according to prior art.
MeCSNH,

The use of extremely toxic potassium cyanide makes this process unsuitable for manufacturing purposes.
Route A

In Japanese patent JP3202607B Febuxostat ethyl ester is prepared, according to the above scheme, through two similar routes. Route A uses flash column chromatography for the purification of the hydroxylamine reaction product, while Route B suffers from low yield and the use of chlorinated solvents for recrystallization. In addition, the reaction solvent is, in both cases, formic acid which causes severe skin burns and eye damage to humans. Formic acid is also corrosive towards metal-based materials of construction (MOC), like stainless steel and nickel alloys, limiting the options, essentially, to glass reactors or vessels. The drawbacks of using this solvent are also related to the high volumes of formic acid required per batch, which hinder the waste treatment.
In CN101723915B focus is made to the improvement of the hydroxylamine reaction. Formic acid is replaced with dimethylformamide (DMF) and other solvents. However, according to widely used organic chemistry textbooks, such as March’s Advanced Organic Chemistry, pi 287, 6th edition, M. B. Smith and J. March, ISBN 0-471-72091-7, the mechanism of the reaction involves the formation of an oxime, upon the action of hydroxylamine, which further dehydrates to form a nitrile, with the aid of a suitable reagent, for example formic acid, or acetic anhydride. In the absence of such a reagent, it is expected that the reaction will, at least, not lead to completion, thereby leading to low yields and undesired impurity levels, namely the intermediate oxime. Such impurities, arising from the reactions of the process and which exhibit similar structure of the desired product, are often difficult to remove with common industrial techniques, e.g. crystallization.
In WO2010142653A1 the intermediate Febuxostat ethyl ester is prepared from 4-cyanophenol, through a five-step process. Febuxostat can be prepared from its respective ethyl ester via alkaline hydrolysis, as in the previous case.
OH

1: patents US5614520 febuxostat synthetic process:
2: Patent JP1994329647 febuxostat synthesis
PATENT
https://www.google.com/patents/CN102936230A?cl=en
Gout occurs because the body produces too much uric acid and renal clearance capacity decreased, uric acid accumulation in the body, leading to urate crystals deposited in the joints and organs. Therefore, it means the treatment of gout usually taken to be: to promote uric acid excretion and suppression of uric acid, and the use of appropriate measures to improve symptoms. Uric acid formation and purine metabolism, the final step in the purine metabolism, hypoxanthine generation xanthine xanthine oxidoreductase (XOR) effect, further generate uric acid, inhibit the activity of the enzyme can effectively reduce uric acid production. Febuxostat is currently the world’s newly developed XOR inhibitors, which act by highly selective to the oxidase, reduce uric acid synthesis, reduce uric acid levels, so as to effectively treat the disease ventilation.
Compared with the traditional treatment of gout drug allopurinol, febuxostat has obvious advantages: (1) allopurinol reduced the XOR only inhibit rather than febuxostat of oxidized and reduced form are XOR significant inhibition, thus reducing the role of uric acid, which is more powerful and lasting; (2) Since allopurinol is a purine analogue, the inevitable result of the purine and other activity related to the impact of pyridine metabolism. So allopurinol treatment should be repeated large doses of the drug to maintain a high level. Which also brought serious or even fatal adverse reactions due to drug accumulation due.Instead of febuxostat non-purine XOR inhibitors, so it has better security.
Document TMX-67. Drugs Fut2001, 26, I, 32, and EP0513379, US5614520, W09209279, public
The detailed preparation febuxostat. Using 3-nitro-4-hydroxybenzaldehyde as the starting material is first reacted with hydroxylamine hydrochloride, to give 3-nitro-4-hydroxybenzonitrile. In effect then HCl, reaction with thioacetamide to give 3-nitro-4-hydroxy-thiobenzamide. Closed loop then reacted with 2-chloro ethyl acetoacetate to give 2- (3_ nitro-4-hydroxyphenyl) methyl-5-thiazolyl -4_ carboxylic acid ethyl ester. Followed by potassium carbonate effect, isobutane is reacted with bromo, to give 2- (3_ nitro-4-isobutyloxyphenyl) -4-methyl-5-carboxylic acid ethyl ester. Under the catalytic action of palladium on carbon, hydrogen reduction to give 2- (3-amino-4-isobutyloxyphenyl) -4-methyl-5-thiazole carboxylic acid ethyl ester. Followed by diazotization with sodium nitrite occur, was added cuprous cyanide and potassium cyanide, to give 2- (3-cyano-4-isobutyloxyphenyl) -4-methyl-5-thiazolecarboxylic acid ethyl ester. Finally, under the effect of the hydrolysis of sodium hydroxide, to give the product 2- (3-cyano-4-isobutyloxyphenyl) -4-methyl – thiazole-5-carboxylic acid, to obtain febuxostat.The process route is as follows:
This route in the preparation of febuxostat, there are many disadvantages: raw 3-nitro-4-hydroxybenzaldehyde in the country is difficult to buy; requires the use of palladium-carbon catalytic hydrogenation reaction under the factory equipment higher requirements, there is a certain danger; the cyano preparation, the need to use sodium nitrite diazotization, could easily lead to corrosion of equipment; the cyano preparation, the need to use toxic cyanide copper, potassium cyanide, pollution, higher risk.
Document JP1994329647, JP1998045733, US3518279 reported another synthesis of febuxostat
Methods. From 4-hydroxy-thiobenzamide as a starting material, and the cyclization reaction to give ethyl 2-bromo-acetyl occurred
2- (4_ hydroxyphenyl) -4_ methyl-5-carboxylic acid ethyl ester in polyphosphoric acid effect, HMTA (hexamethylene tetramine) reacts with 2- (3_ aldehyde – 4-hydroxyphenyl) methyl-5-thiazolyl -4_ carboxylic acid ethyl ester. Then two cases: the first case, the effect of potassium carbonate, is reacted with isobutane to give bromo-2- (4-isobutyloxyphenyl 3_ aldehyde) -4_-methyl-5- thiazole carboxylic acid ethyl ester, and then reacted with hydroxylamine hydrochloride to give 2- (3_-cyano-4-isobutyloxyphenyl) -4_-methyl-5-thiazole carboxylic acid ethyl ester; second case is the first with hydroxylamine hydrochloride to give 2- (3_ cyano-4-hydroxyphenyl) methyl-5-thiazolecarboxylic -4_ carboxylic acid ethyl ester, and then under the effect of potassium carbonate, and reacted with isobutane to give bromo-2- (3 _-cyano-4-isobutyloxyphenyl) -4-methyl-5-carboxylic acid ethyl ester.
Finally, under the effect of the hydrolysis of sodium hydroxide, to give the product 2- (3_-cyano-4-isobutyloxyphenyl) -4_ methyl – thiazole-5-carboxylic acid, i.e., to obtain febuxostat . The process route is as follows:
This synthesis route febuxostat process, since the introduction of aldehyde HMTA in PPA (polyphosphoric acid) effect. So there are a lot of phosphorus wastewater, serious environmental pollution, but also because PPA has great viscosity, and therefore difficult to stir the production, operation is extremely inconvenient.
Document Heterocyclesl998, 47,2,857 JP1994345724 also reported the synthesis method of febuxostat, using p-nitrophenyl-carbonitrile as a starting material in the reaction with potassium cyanide in DMSO solvent, and then the carbonate lower potassium catalyzed reaction of isobutane and brominated 1,3-cyano-4-diisobutoxybenzene ether. By reaction with thioacetamide to afford
3-cyano-4-isobutyloxyphenyl thiobenzamide. Under heating, and 2-chloro ethyl acetoacetate, ring closure reaction occurs to give 2- (3-cyano-4-isobutyloxyphenyl) -4-methyl-5-carboxylic acid ethyl ester, and finally hydrolysis under the effect of sodium hydroxide, to give the product 2- (3-cyano-4-isobutyloxyphenyl) -4-methyl – thiazole-5-carboxylic acid, to obtain febuxostat.
The present invention febuxostat new technology system, comprising the steps of:
(1) 2-hydroxy-5-cyano – NaSH reacted with benzaldehyde to give 4-hydroxy-3- aldehyde thiobenzamide;
(2) the step (I) to give 4-hydroxy-3-aldehyde thiobenzamide reaction with ethyl 2-halo-acetyl, closed
Ring to give 2- (3-aldehyde-4-hydroxyphenyl) -4-methyl-5-ethoxycarbonyl thiazole;
X is a halogen, preferably Cl or Br;
(3) the step (2) to give 2- (3-aldehyde-4-hydroxyphenyl) -4-methyl-5-ethoxycarbonyl thiazole with hydroxylamine in formic acid in the reaction solution to give 2- (3- cyano-4-hydroxyphenyl) -4-methyl-5-ethoxycarbonyl thiazole;
(4) The step (3) to give 2- (3-cyano-4-hydroxyphenyl) -4-methyl-5-ethoxycarbonyl thiazole isobutane with halo effect in potassium carbonate, to give 2- (3-aldehyde-4-isobutyloxyphenyl) -4-methyl-5-ethoxycarbonyl thiazole;
(5) in step (4) to give 2- (3-aldehyde-4-isobutyloxyphenyl) -4-methyl-5-ethoxycarbonyl-thiazol-off hydrolyzable ester group, to obtain a non-Tendon Disposition Tanzania.
[0011] Scheme of the method is as follows:
X is halogen, may be Cl, Br;
Preparation 5 febuxostat Example
To a 500ml reaction flask was added 200ml of absolute ethanol, the product of Step 4 was added with stirring (60g, O. 174mol),
5% sodium hydroxide was added 100ml. Stirring heated to 40 degrees, until it is completely dissolved. 40 degrees heat, reaction 4h. The reaction by TLC tracking. After completion of the reaction, the reaction solution was added 10% hydrochloric acid to adjust the pH to 3, the precipitated solid was filtered. And dried to give a pale yellow solid. Dried over anhydrous recrystallized from methanol to give 31. 2g of white crystals, yield 56.7%.
TLC monitoring of the reaction. Eluent: petroleum ether / ethyl acetate = 3: 1 Melting point:. 201 · 7 ~202 30C (literature value 201 ~202 ° C)
1H-NMR δ:. 1 01 (m, 6H), 2.06 (m, lH), 2.57 (m, 3 H), 3.96 (d, 2H), 7.30 (d, lH), 8.13 (m, 1H), 8. 19 (d, 1H);
MS (m / z):. 316 O (M +)
Infrared detection: 3550-3400cm_1; 2961, 2933,2874; 2227cm_1; 1680U604U511cm_1; 1425cm_1; 1296U283CHT1;
Elemental analysis for C, Η, N, S purified product actual measurement of the content of C, H, N, S content: C:. 60 57%, H:. 5 32%, N:. 8 86%, S: 10. 16%; theoretical value: In C16H16N203S calculated C: 60 74%, H: 510%, N: 885%, S: 1014%..
CLIP
Facile OnePot Transformation of Arenes into Aromatic Nitriles …

Patent
Clip
synthesis describes synthesis of febuxostat (I) from 4-hydroxybenzonitrile (II) in six stages. The synthesis shown is a short, concise route and does not require use of poisonous reagents such as KCN (14). Compound II was converted to 4-hydroxybenzothioamide (III) with 85% yield using NaHS in the presence of hydrated magnesium chloride as Lewis acid. Intermediate III, on cyclization with ethyl-2-chloroacetoacetate, gave thiazole ester (IV) with quantitative yield. In these two stages, the source of potential impurities was identified as an ortho isomer (i.e., 2-hydroxybenzonitrile), which can lead to Impurity VIII and subsequently to Impurity IX . Impurities VIII and IX can be controlled in starting material II with appropriate specification.
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The ortho formylation of hydroxyl compound IV by using Duff condition (hexamine/TFA) gave aldehyde V (15). The major impurity identified in this reaction was dialdehyde X. Although we have used only 1.0 equivalence of hexamine with respect to Compound IV, the dialdehyde X impurity was formed to a 5-10% ratio in only 2.5 h. It is, therefore, impossible to get rid of this impurity during the reaction, and only effective recrystallization will eliminate it. Impurity X was minimized (≤ 2%) by recrystallization using IPA/H2O (3:5) to get aldehyde V with 50% yield and & #8805; 97% HPLC purity.
Aldehyde V, on alkylation with isobutyl bromide in the presence of potassium carbonate base, gave compound VI with 90% yield. In this stage, Impurities XI and XII were alkylations of carryover Compound IV and dialdehyde, respectively. Two more isomeric impurities n-butyl-aldehyde XIII and 1-methyl propyl-aldehyde XIV were also identified in this stage. Both isomeric impurities can be controlled with appropriate specification for isobutyl bromide. The reaction of Compound VI with hydroxylamine hydrochloride and sodium formate in formic acid at reflux temperature gave Compound VII with 85% yield. Impurities XIII and XIV will also carry forward to impurities n-butyl-nitrile XV and 1-methyl propyl-nitrile XVI, respectively.
In the final step, Compound VII was hydrolyzed using sodium hydroxide in a MeOH:THF:H2O (1:1:1) solvent combination to yield febuxostat (85%). During saponification, methyl ester Impurity XVII was identified via trans-esterification. Its hydrolysis was comparatively slower than its ethyl isomer VII. One way to avoid Impurity XVII is to replace methanol with ethanol. Carryover impurities XI, XV, and XVI were also hydrolyzed to their respective acid derivatives impurities XVIII, XIX, and XX. However, the acid derivatives of impurities X and XII were unexpectedly absent as impurities. It is believed that, because they were present in low concentrations during workup, they were eliminated in the mother liquor. Two additional impurities, amide XXI and diacid XXII, formed by the side reaction of the febuxostat nitrile group with sodium hydroxide, were identified during saponification. The amide XXI and diacid XXII impurities can be controlled by using appropriate equivalence of sodium hydroxide and controlled reaction time. Febuxostat, on acetone recrystallization and seed Crystal A at 45°C, gave pure febuxostat with 75% yield.

http://www.pharmtech.com/investigation-various-impurities-febuxostat
Febuxostat is an inhibitor of xanthine oxidase, and was developed by Teijin pharma. This compound is known as a new drug that is effective against gout and hyperuricemia, and it has been 40 years since the last time a drug of this kind of drug was developed.
Febuxostat has therefore gained a lot of popularity and it has already been accepted as a drug in Europe, USA, Korea and Japan. The synthesis of this molecule have been reported in patents by Teijin pharma as shown below.[1,2]
Recently, Itami group was reported the rapoid synthesis of febxostat by using Ni-catalyzed direct coupling of azoles and arylhalides[3]
References
Sorbera, L.A.; Castaner, J.; Rabasseda, X.; Revel, L.; TMX-67. Drugs Fut 2001, 26, 1, 32
[1] Hasegawa, M.; A facile one-pot synthesis of 4-alkoxy-1,3-benzenedicarbonitrile. Heterocycles 1998, 47, 2, 857. [2] Hasegawa, M.; Hasegawa, M.; Komoriya, K. (Teijin Ltd.); Cyano cpds. and their preparation method. JP 1994345724 . [3] “Nickel-Catalyzed Biaryl Coupling of Heteroarenes and Aryl Halides/Triflates”
Canivet, J.; Yamaguchi, J.; Ban, I.; Itami, K. Org. Lett. 2009, 11, 1733-1736. DOI: 10.1021/ol9001587
Ni-based catalytic systems for the arylation of heteroarenes with aryl halides and triflates have been established. Ni(OAc)2/bipy is a general catalyst for aryl bromides/iodides, and Ni(OAc)2/dppf is effective for aryl chlorides/triflates. Thiazole, benzothiazole, oxazole, benzoxazole, and benzimidazole are applicable as heteroarene coupling partners. A rapid synthesis of febuxostat, a drug for gout and hyperuricemia, is also demonstrated.
A CLIP
A final example of a thiazole containing drug is given in the novel xanthine oxidase inhibitor febuxostat (359, Uloric) which was approved by the FDA in 2009. This inhibitor works by blocking xanthine oxidase in a non-competitive fashion. Consequently, the amount of the oxidation product uric acid is reduced. Thus it is an efficient treatment for hyperuricemia in gout. In order to prepare febuxostat first a synthesis of the noncommercial 4-isobutoxy-1,3-dicyanobenzene building block (363), has to be conducted. An elegant way of achieving this was shown through the reaction of 4-nitrocyanobenzene (360) with potassium cyanide in dry DMSO followed by quenching with isobutyl bromide under basic conditions (Scheme 70). It is suggested that a Meisenheimer-complex intermediate 361 is initially formed, which after rearomatisation, undergoes nucleophilic aromatic substitution of the nitro group by the DMSO solvent [107]. Upon hydrolysis and O-alkylation the desired 4-isobutoxy-1,3-dicyanobenzene (363) is obtained in good overall yield. Subsequently, the less hindered nitrile is converted to the corresponding thioamide 365 in an intriguing reaction using thioacetamide (364). The thiazole ring is then formed by condensation with chloroacetoacetate 366 followed by ester hydrolysis (Scheme 70).
107 Hasegawa, M. Heterocycles 1998, 47, 857–864. doi:10.3987/COM-97-S(N)89
Paper | Special issue | Vol 47, No. 2, 1998, pp.857-864
Masaichi Hasegawa
*Teijin Institute, Bio-Medical Research, Asahigaoka 4-3-2, Hino, Tokyo 191, Japan
2-(3-Cyano-4-isobutoxyphenyl)-4-methylthiazole-5-carboxlic acid (TEI-6720) was prepared. The introduction of cyano group to 4-nitrobenzonitrile with KCN in dry DMSO followed by quenching with alkyl halide afforded the key intermediates, 4-alkoky-1,3-benzenedicarbonitriles, in good yield. The reaction was completed in dry DMSO, while no reaction occurred in dry DMF. This observation can be suggested by the participation of DMSO in the reaction.
http://www.beilstein-journals.org/bjoc/single/articleFullText.htm?publicId=1860-5397-7-57#S70
A CLIP
Synthesis and characterization of process-related impurities of an anti-hyperuricemia drug-Febuxostat
Venkateswara Rao Vallu,$ Krunal Girishbhai Desai, Sandip Dhaya Patil, Rajendra Agarwal, Pratap Reddy Padi and Mahesh Reddy Ghanta
*Process Research Laboratory-I, Research & Development Centre, Macleods Pharmaceuticals Ltd, G-2, Mahakali Caves Road, Shantinagar, Andheri (East), Mumbai, Maharastra, India
$Department of Chemistry, Pacific University, Pacific Hills, Airport Road, Pratap Nagar Extension, Debari, Udaipur, Rajasthan, India _____________________________________________________________________
Der Pharma Chemica, 2014, 6(3):300-311 (http://derpharmachemica.com/archive.html)
http://derpharmachemica.com/vol6-iss3/DPC-2014-6-3-300-311.pdf
Synthesis of 2-(3-cyano-4-isobutoxyphenyl)-4-methylthiazole-5-carboxylic acid (1) [10] A solution of 2-(3-cyano-4-isobutoxyphenyl)-4-methylthiazole-5-carboxylic acid (1 tech grade, 5.0 g, 0.015 mol.) in methanol (50.0 mL) was heated the reaction mass at 60-65°C till clear solution was obtained. Water (50.0 mL) was added drop wise into reaction mass with in 30.0 min. at 60-65°C. Resultant white crystalline solid was filtrated, Mahesh Reddy Ghanta et al Der Pharma Chemica, 2014, 6 (3):300-311 _____________________________________________________________________________ 302 http://www.scholarsresearchlibrary.com washed with water (10.0 mL) and dried in vacuum tray drier at 50-55°C under vacuum to give
2-(3-cyano-4- isobutoxyphenyl)-4-methylthiazole-5-carboxylic acid (1). Yield: 95.0 % (4.75 g)
mp 239°C. Purity by HPLC: 99.74 % (10.2 min. retention time),
Anal. Calcd for C16H16N2O3S: C, 60.74; H, 5.10; N, 8.85. Found: C, 60.70; H, 5.11; N, 8.87 %;
IR (KBr) υmax (in cm−1): 3834.61, 3742.03, 3680.30, 3556.85, 3456.55, 2962.76, 2877.89, 2661.85, 2546.12, 2353.23, 2229.79, 2168.06, 2029.18, 1921.16, 1790.00, 1674.27, 1604.83, 1512.24, 1427.37, 1381.08, 1280.78, 1172.76, 1118.75, 1010.73, 918.15, 833.28, 771.55, 725.26, 648.10, 524.66, 462.93; 1H NMR (300 MHz, CDCl3 or DMSO-d6) δH (in ppm): 1.00-1.02 (d, 6H, (CH3)2-CH-), 2.49-2.50 (m, 1H, (CH3)2-CH-), 3.97-3.99 (d, 2H, -CH-CH2−), 7.33–8.25 (d, dd, 3H, Ar-H), 2.64 (s, 3H, -CH3), 13.39 (s, 1H, -COOH);
13C NMR (300 MHz, DMSO–d6) δC (in ppm) (Positiona ): 166.3 (l), 162.9 (p), 162.2 (n), 159.6 (e), 133.1 (g), 131.6 (i), 125.5 (m), 123.0 (h), 115.5 (k), 114.0 (f), 101.7 (j), 75.2 (d), 27.7 (b), 18.8 (a, c), 17.1 (o);
MS m/z (%) (70 eV): m/z =317.0 (100.0 %) [M+1], 318.0 (16.0 %) [M+2], 403.0 (63.0 %), 512.0 (47.0 %), 482.0 (46.0 %), 405.0 (27.0 %), 468.0 (25.0 %), 570.0 (24.0 %).
PATENT
| WO 2012066561 |
As per the present invention, hydroxylamine hydrochloride is added to compound of Formula-Ill in presence of a polar aprotic solvent like DMSO, DMA, ACN or DMF. To this reaction mixture acetyl halides or sulfonyl chlorides are added and temperature raised to 70 -80 °C. Acetyl halides are selected from acetyl bromide or acetyl chloride. Sulfonyl chlorides are selected from methane sulfonyl chloride or para toluene sulfonyl chloride. To this reaction mixture a base selected from alkali metal carbonates like potassium carbonate or sodium carbonate, preferably potassium carbonate and alkyl halide selected from isobutyl bromide is successively added. The reaction mass is washed with water and compound of Formula-II is isolated. In one embodiment the present invention provides, process for the preparation of Febuxostat comprising the steps of:
a) reacting the compound of Formula-III(a) with hydroxylamine hydrochloride in presence of organic solvent;
Formula-III(a)
b) adding acyl halides or sulfonyl chlorides to the reaction mixture;
c) optionally isolating compound of Formula- IV (a)
Formula-IV(a)
d) reacting with isobutyl bromide in presence of base;
e) isolating the compound of Formula-II(a); and
FormuIa-II(a)
f) hydrolyzing the compound of Formula-II(a) to get Febuxostat.
The following examples are provided to illustrate the process of the present invention. They, are however, not intended to limiting the scope of the present invention in any way and several variants of these examples would be evident to person ordinarily skilled in the art. Experimental procedure:
Example – 1: Preparation of Ethyl-2-(3-cyano-4-isobutoxy phenyl)-4-methyI thiozole -5-carboxylate
A mixture of 10. Og of Ethyl -2-(3-formyl-4-hydroxy phenyl)-4-methyl thiozole -5- carboxylate and 2.85 g of hydroxylamine hydrochloride were stirred for 30 minutes in 40 g of Dimethyl sulfoxide. To this reaction mixture 3.3 grams of acetyl chloride was added and stirred at 70 -80°C for 2-3 hours. Reaction mass was cooled to room temperature and to this 19 g of potassium carbonate and 19 g of isobutyl bromide was added successively. The reaction mass was stirred for 5 hours at 70-80°C. Reaction mass was diluted with 200 ml of purified water. The reaction mass was filtered and washed with purified water to give 10.0 g of Ethyl-2-(3-cyano-4-isobutoxy phenyl)-4-methyl thiozole -5-carboxyltae (yield 84.0%)
Example – 2: Preparation of Ethyl-2-(3-cyano-4-hydroxyphenyl)-4-methyl thiozole – 5-carboxylate
A mixture of 10. Og of Ethyl-2-(3-formyl-4-hydroxy phenyl)-4-methyl thiozole -5- carboxylate and 2.85 g of hydroxylamine hydrochloride were stirred for 30 minutes in 30 g of Dimethylformamide. To this reaction mixture 3.3 grams of acetyl chloride was added and stirred at 90°C for 2-3 hours. Reaction mass was cooled to room temperature and diluted with 100 ml of water and stir for 2 hours. The reaction mass was filtered and washed with purified water to give 10.0 g of Ethyl-2-(3-cyano-4-hydroxy phenyl)-4- methyl thiozole -5-carboxyltae (yield 99.0%).
Example – 3: Preparation of Ethyl 2-(3-cyano-4-isobutoxy phenyl)-4-methyl thiozole -5-carboxylate
A mixture of 10. Og of Ethyl-2-(3-cyano-4-hydroxy phenyl)-4-methyl thiozole -5- carboxylate, 30 g of NMP, 9.6 g of potassium carbonate and 7.2 g of isobutyl bromide were stirred for 3 hours at 90°C. Reaction mass was diluted with 100 ml of purified water. The reaction mass was filtered and washed with purified water and ethanol to give 10.5 g of Ethyl-2-(3-cyano-4-isobutoxy phenyl)-4-methyl thiozole -5-carboxyltae (yield 88.0%). Example – 4: Preparation of 2-(3-cyano-4-isobutoxy phenyl)-4-methyl thiozole -5- carboxylic acid
A mixture of 10. Og of Ethyl-2-(3-cyano-4-isobutoxy phenyl)-4-methyl thiozole -5- carboxyltae, 2.0g of sodium hydroxide was heated at 45-60°C in 75 ml of aqueous methanol for 1 hour. Reaction mass was cooled to ambient temperature and pH adjusted to 2.0 to 2.5 with dilute hydrochloric acid and precipitated crystal was collected by filtration to give 8.8g of 2-(3-cyano-4-isobutoxy phenyl)-4-methyl thiozole -5-carboxylic acid (yield 95.8%).
Example – 5-13: Preparation of 2-(3-cyano-4-isobutoxy phenyl)-4-methyl thiozole – 5-carboxylic acid
The above compound was prepared by following the procedure as disclosed in Example- 4, using the below listed solvents instead of aqueous methanol.
Example – 14: Preparation of pure 2-(3-cyano-4-isobutoxy phenyl)-4-methyl thiozole -5-carboxylic acid
10.0 g of 2-(3-cyano-4-isobutoxy phenyl)-4-methyl thiozole -5-carboxylic acid was dissolved in 100 ml of ethanol at reflux temperature. After dissolution reaction mass was cooled and precipitated crystal was collected by filtration to give 9.6 g of pure 2-(3- cyano-4-isobutoxy phenyl)-4-methyl thiozole -5-carboxylic acid (yield 96%).
PATENT
KR 201603732
PATENT
WO 2015018507
https://www.google.com/patents/WO2015018507A2?cl=en



EXPERIMENTAL
of compound of formula lib

Dissolve 14.14g of ethyl 2-(3-formyl-4-hydroxyphenyl)-4-methylthiazole-5-carboxylate (Formula III) in 55 ml dimethylformamide, at ambient temperature. Add 40g of potassium carbonate, along with 15.9 ml isobutyl bromide. Heat the reaction to 75-80 °C and stir for 4 hours. Cool to 25-30 °C, while 165 ml process water is added. Further cool to 0-5 °C and stir for 30 minutes at this temperature. Filter off the precipitated solid and wash the filter cake with 55 ml process water. The wet cake is dried under vacuum at 40 °C for 7 hours, to furnish 16.43 g of ethyl 2-(3-formyl-4-isobutoxyphenyl)-4-methylthiazole-5-carboxylate (Formula lib).
of compound of formula Illb

In a 25 mL round-bottomed flask charge under stirring at 25-30 °C, 1.0 g (2.88 mmol) of ethyl 2-(3-formyl-4-isobutoxyphenyl)-4-methylthiazole-5-carboxylate in 3.0 mL dimethylformamide. Add 34 mg (0.19 mmol) copper acetate under stirring at 25-30 °C. Flush with oxygen (02) and add 0.66 ml (34.92 mmol) 25% aqueous ammonia. Flush again with 02. Heat the reaction mixture to 80-82 °C overnight. Check the progress of the reaction by TLC (cyclohexanerethyl acetate 3:1). Cool reaction mass to 25-30 °C. Add 25mL ethyl acetate and 25mL brine at the reaction mass, separate organic layer and extract aqueous layer twice with 25mL ethyl acetate. Combine organic layers, dry over anhydrous sodium sulfate, filter off and concentrate till dry. The residue is purified with column chromatography (cyclohexane:ethyl acetate 9:1). afforded 0.754g of ethyl 2-(3-cyano-4-isobutoxyphenyl)-4-methylthiazole-5-carboxylate (Formula Illb) Yield: 75.4%.
EXAMPLE 3: Preparation of compound of formula Illb

In a 25 mL round-bottomed flask charge under stirring at 25-30 °C, 0.17 g (0.49 mmol) of ethyl 2-(3-formyl-4-isobutoxyphenyl)-4-methylthiazole-5-carboxylate in 2.5 mL tetrahydrofuran. Add 2.9 mL (153.43 mmol) 25% aqueous ammonia, under stirring at 25-30 °C. Add 137 mg (0.54 mmol) iodine (I2) to the reaction mass, stir the reaction mixture at 25-30 °C for 15-30 min. Check the progress of the reaction by TLC (cyclohexane: ethyl acetate 3:1). Starting material is consumed. Add 2.5 mL 5% w/v aqueous sodium thiosulfate Na2S203 and 15mL ethyl acetate at the reaction mass, separate organic layer and extract twice aqueous layer with 15mL ethyl acetate. Combine organic layers, dry over anhydrous sodium sulfate, filter off and concentrate till dry. 0.158g of ethyl 2-(3-cyano-4-isobutoxyphenyl)-4-methylthiazole-5-carboxylate (Formula Illb) are collected.
EXAMPLE 4: Preparation of Febuxostat

In a 100 ml 2-neck round-bottomed flask charge 2.407g of ethyl-2-(3-cyano-4-isobutoxyphenyl)-4-methylhiazole-carboxylate in 20ml tetrahydrofuran under stirring, at 25-35 °C, 0.748g of sodium hydroxide and heat reaction mass to 60-65 °C for approximately 8 hrs. Check the progress of the reaction by TLC (cyclohexane:ethyl acetate 3:1). Cool reaction mass to 0-5 °C and add 50 ml process water keeping temperature within 0-5 °C. Adjust pH to 1-2 with 4.5 ml 6 N hydrochloric acid, keeping temperature within 0-5 °C. Warm up reaction mass to 25-30 °C and stir reaction mass at the above temperature for 15 min. Filter off the precipitated solid through Buchner funnel under reduced pressure, spray wash with 2 ml process water and suck dry for 20-30 min. Transfer the crude solid in a 50 ml round-bottomed flask, charge 12 ml process water and 12 ml acetone at 25-30°C. Heat the reaction mass to 50-60 °C for 60 min. Cool down reaction mass to 0-5 °C and stir for 60 min at the above temperature. Filter off the precipitated solid though Buchner funnel under reduced pressure, spray wash with 2 ml of a 1 : 1 mixture of acetone and process water and suck dry for 30-45 min. Dry under vacuum at 60 °C. 1.821g of (compound I) Febuxostat are collected, Purity: 82.6%, Yield: 0.62w/w.
on of compound of formula Ilia

In a 50 mL round-bottomed flask charge under stirring 0.5g (1.72 mmol) of ethyl 2-(3-formyl-4-hydroxyphenyl)-4-methylthiazole-5-carboxylate in 8.6 mL THF, at 25-30 °C. Add 10.3 mL (544.94 mmol) 25% aqueous ammonia, under stirring at 25-30 °C. Add 480 mg (1.89 mmol) iodine (I2) to the reaction mass, stir the reaction mixture at 25-30 °C for 15-30 min. Check the progress of the reaction by TLC (cyclohexane: ethyl acetate 1 :1). Starting material is consumed. Add 8.6 mL 5% w/v aqueous thiosulfate and 40 mL ethyl acetate at the reaction mass, separate organic layer and extract aqueous layer twice with 40 mL ethyl acetate. Combine organic layers, dry over anhydrous sodium sulfate, filter off and concentrate to dryness. Purification of the residue with column chromatography (cyclohexane: ethyl acetate 3: 1) afforded 0.213 g of ethyl 2-(3-cyano-4-hydroxyphenyl)-4-methylthiazole-5-carboxylate (Formula Ilia). Yield : 42.6%.
EXAMPLE 6: Preparation of compound Illb
Dissolve 2.2 g of ethyl 2-(3-cyano-4-hydroxyphenyl)-4-methylthiazole-5-carboxylate (Formula VI) in 7 ml dimethylformamide and to this mixture add 6.6 g of potassium carbonate and 3.14 g of isobutyl bromide. Stir the reaction at 75 °C for 15 hours and then cool to 40 °C. Add 15 ml process water and cool to 0-5 °C. Filter the precipitated solid off and wash with 15 ml process water, which, after drying, affords 2.28 g of ethyl 2-(3-cyano-4-isobutoxyphenyl)-4-methylthiazole-5-carboxylate (Formula Illb).
EXAMPLE 7: Preparation of compound I (Febuxostat)
In a 100 ml 2-neck round-bottomed flask charge 2.131 g of ethyl-2(3-cyano-4-isobutoxyphenyl)-4-methylhiazole-carboxylate, 64 ml methanol and 2.5 ml process water are added under stirring at 25-35 °C. Add 1.718 g potassium carbonate and heat reaction mass to reflux for approximately 2-3 hrs. Check the progress of the reaction by TLC (cyclohexane: ethyl acetate 3:1). Cool reaction mass to 20-25 °C. Concentrate solvent at below 40 °C. To the residue add 43 ml process water, 21 ml ethyl acetate and stir for 30 min at 25-35 °C. Separate layers and transfer aqueous layer in a 100 ml round-bottomed flask. Adjust pH to 2.3-2.7 with 25 ml 1 N hydrochloric acid, at 25-35 °C. Warm up reaction mass to 40 °C and stir reaction mass at this temperature for 60-90 min. Cool down reaction mass to 25-35 °C. Filter off the precipitated solid through Buchner funnel under reduced pressure, spray wash with 5 ml process water and suck dry for 30-45 min. Dry under vacuum at 60 °C. 1.708g of (compound I) Febuxostat are collected, Purity: 86.7%, Yield: 0.69w/w.
EXAMPLE 8: Preparation of Febuxostat crystalline form III
In a 250 mL round-bottomedflask charge under stirring at 25-30 °C 10 g of crude 2-(3-cyano-4-isobutoxyphenyl)-4-methylthiazole-5-carboxylic acid (Febuxostat) in 200 mL ethyl acetate. Heat reaction mass to reflux and stir for 30 min. Cool reaction mass to 25-30°C. Warm again reaction mass and partially distill off solvent from the reaction mass at temperature below 40 °C under reduced pressure. Cool reaction mass to 25-30°C. Filter off the precipitated solid through Buchner funnel under reduced pressure and spray wash with 10 mL ethyl acetate. Dry under vacuum at 60°C. 8.5 g of Febuxostat are collected. Yield: 85 % w/w. XRPD of crystalline compound is in accordance with the one reported in Chinese patent CN101412700B.
PATENT
CN 104418823
https://www.google.com/patents/CN104418823A?cl=zh

PATENT
CN 103588723
https://www.google.com/patents/CN103588723A?cl=zh
Chinese patent CN1275126 described by the Japanese company Teijin invention relates febuxostat Form A, B, C, D, G, and six kinds of amorphous and crystalline preparation method, reported in the literature Form A relatively stable . The method used is a solvent of methanol and water, patent phase diagram (Figure 7 Zone I) can be obtained in anhydrous crystalline Form A (hereinafter referred to as “Form A”), the mixing process by a temperature and the formation of methanol and water to determine the composition of the solvent, and the need to add a certain amount of Form a as a seed crystal to induce precipitation of crystals to control crystallization conditions are very harsh, operable range is very small, easy to form methanol solvate, hydrate or stable crystalline type C, to obtain reproducible single crystal type a low, it is difficult to achieve industrial production, and no mention of the preparation of Form a yield and purity in this patent.
[0011]
[0012] Chinese patent CN102267957A invention discloses a method for preparing febuxostat Form A, the solvent is preferably acetone, dissolved into 25 ~ 40 ° C was allowed to stand, when there began to crystallize when stirred for 20 to 40 minutes, then placed in -15 ~ 0 ° C to continue the crystallization of 8 to 10 hours. The crystallization process need to well below zero, when industrial mass production, resulting in high production costs, is not conducive to industrial production, the process yield up to 95.4%.
[0013] Chinese patent CN101139325 of Example 7 discloses the preparation of Form A with acetone method, although the process is simple, but the yield is low, only 50%.
[0014] Although the Chinese patent CN101684108A isopropyl alcohol as a solvent is disclosed a method for preparing crystalline form, the crystalline form of preparation is used to cool and heat a phased manner was allowed to stand, the crystallization temperature, long crystallization time, about 30 hours, the yield is low, and its products are not crystalline Form A.
[0015] In addition, Chinese patent CN101525319A, CN101805310, CN101926795A, CN101926794, W02012020272A2 are disclosed ethanol as a solvent or aqueous ethanol as a solvent preparation methods, and its products are crystalline ethanol solvate.
[0016] World Patent W02011139886A2 discloses the use of a mixed solvent of alcohol, and its products are not obtained polymorph A0
PAPER
Letters in Organic Chemistry (2015), 12(3), 217-221
Author(s): Xiao Long Li, Rui Qiu, Wei Li Wan, Xu Cheng, Li Hai and Yong Wu
Affiliation: Key Laboratory of Drug Targeting of Education Ministry, West China School of Pharmacy, Sichuan University, Chengdu 610041, China.
Graphical Abstract:

Total synthesis of three Febuxostat metabolites, named 67M-1, 67M-2, and 67M-4,is described in this article. Through condensation of the key intermediate compound A with different side chains, and then oxidation and hydrolysis, we obtained three target compounds with an overall yield of 19.5%-28.0%.
VOLUME: 12
ISSUE: 3
Page: [217 – 221]
Pages: 5
DOI: 10.2174/1570178612666150108000805, http://www.eurekaselect.com/127479/article

ULORIC (febuxostat) is a xanthine oxidase inhibitor. The active ingredient in ULORIC is 2-[3-cyano-4-(2-methylpropoxy) phenyl]-4-methylthiazole-5-carboxylic acid, with a molecular weight of 316.38. The empirical formula is C16H16N2O3S.
The chemical structure is:
![]() |
Febuxostat is a non-hygroscopic, white crystalline powder that is freely soluble in dimethylformamide; soluble in dimethylsulfoxide; sparingly soluble in ethanol; slightly soluble in methanol and acetonitrile; and practically insoluble in water. The melting range is 205°C to 208°C.
LORIC tablets for oral use contain the active ingredient, febuxostat, and are available in two dosage strengths, 40 mg and 80 mg. Inactive ingredients include lactose monohydrate, microcrystalline cellulose, hydroxypropyl cellulose, sodium croscarmellose, silicon dioxide and magnesium stearate. ULORIC tablets are coated with Opadry II, green.
| CN1642546A * | Mar 28, 2003 | Jul 20, 2005 | Teijin Ltd. | Containing a single crystalline solid preparation |
| CN102471295A * | Jul 14, 2010 | May 23, 2012 | Teijin Pharma Ltd. | The method of manufacturing the poor solvent additive method of 2- (3-cyano-4-isobutyl-phenyl) -4-methyl-5-carboxylic acid crystalline polymorph of |
| EP2502920A1 * | Mar 25, 2011 | Sep 26, 2012 | Sandoz Ag | Crystallization process of Febuxostat from A |
| JP2011020950A* | Title not available |
| WO2015018507A3 * | Jul 30, 2014 | Oct 22, 2015 | Pharmathen S.A. | A novel process for the preparation of febuxostat |
| CN103304512A * | Jun 4, 2013 | Sep 18, 2013 | 华南理工大学 | Preparation method for febuxostat |
| WO2011031409A1 * | Aug 12, 2010 | Mar 17, 2011 | Teva Pharmaceutical Industries Ltd. | Processes for preparing febuxostat |
| JP2834971B2 | Title not available | |||
| JP3202607B2 | Title not available | |||
| JPH1045733A * | Title not available | |||
| US5614520 | Jan 30, 1995 | Mar 25, 1997 | Teijin Limited | 2-arylthiazole derivatives and pharmaceutical composition thereof |
| CN102229581A * | Nov 15, 2010 | Nov 2, 2011 | 邹巧根 | Preparation method for febuxostat intermediate |
| JPH1045733A * | Title not available |
| CN101497589A * | Feb 26, 2009 | Aug 5, 2009 | 沈阳药科大学 | Method for synthesizing 2-(3-cyano-4- isobutoxy phenyl)-4-methyl-carboxylate |
| CN101863854A * | Jun 29, 2010 | Oct 20, 2010 | 沈阳药科大学 | Synthesis method of 2-(3-cyan-4-isobutoxy) phenyl-4-methyl-5-thiazole formic acid |
| JP2706037B2 * | Title not available |
| Reference | ||
|---|---|---|
| 1 | * | HASEGAWA, M. ET AL.: ‘A facile one-pot synthesis of 4-alkoxy-1,3-benzenedicarbonitrile‘ HETEROCYCLES vol. 47, no. 2, 1998, pages 857 – 864 |
| Citing Patent | Filing date | Publication date | Applicant | Title |
|---|---|---|---|---|
| WO2012131590A1 * | Mar 28, 2012 | Oct 4, 2012 | Sandoz Ag | An improved process for preparation of febuxostat and its polymorphic crystalline form c thereof |
| WO2014009817A1 * | Mar 19, 2013 | Jan 16, 2014 | Alembic Pharmaceuticals Limited | Pharmaceutical composition of febuxostat |
| WO2014057461A1 | Oct 10, 2013 | Apr 17, 2014 | Ranbaxy Laboratories Limited | Process for the preparation of crystalline form g of febuxostat |
| Systematic (IUPAC) name | |
|---|---|
|
2-(3-cyano-4-isobutoxyphenyl)-4-methyl-
1,3-thiazole-5-carboxylic acid |
|
| Clinical data | |
| Trade names | Uloric, Adenuric, Atenurix, Feburic, Goturic, Goutex. Generic in several countries.[1] |
| AHFS/Drugs.com | Monograph |
| MedlinePlus | a609020 |
| License data |
|
| Pregnancy category |
|
| Routes of administration |
Oral |
| Legal status | |
| Legal status |
|
| Pharmacokinetic data | |
| Bioavailability | ~49% absorbed |
| Protein binding | ~99% to albumin |
| Metabolism | via CYP1A2, 2C8, 2C9,UGT1A1, 1A3, 1A9, 2B7 |
| Biological half-life | ~5-8 hours |
| Excretion | Urine (~49% mostly as metabolites, 3% as unchanged drug); feces (~45% mostly as metabolites, 12% as unchanged drug) |
| Identifiers | |
| CAS Number | 144060-53-7 |
| ATC code | M04AA03 (WHO) |
| PubChem | CID 134018 |
| IUPHAR/BPS | 6817 |
| DrugBank | DB04854 |
| ChemSpider | 118173 |
| UNII | 101V0R1N2E |
| KEGG | D01206 |
| ChEMBL | CHEMBL1164729 |
| Chemical data | |
| Formula | C16H16N2O3S |
| Molar mass | 316.374 g/mol |
/////////Febuxostat, 144060-53-7, Uloric, Adenuric, Tei 6720, thiazole derivative, inhibitor of XANTHINE OXIDASE, treatment of HYPERURICEMIA, chronic GOUT, FBX, Febugood, Feburic, Febutaz, TMX 67, Zurig
CC1=C(SC(=N1)C2=CC(=C(C=C2)OCC(C)C)C#N)C(=O)O

The heterogeneous palladium-catalyzed Suzuki reactions between model aryl bromides (4-bromoanisole, 4-bromoaniline, 4-amino-2-bromopyridine, and 2-bromopyridine) and phenylboronic acid have been successfully conducted in water with no added ligand at the 100 mL scale using 20–40 mmol of aryl bromide. The product yields associated with these substrates were optimized, and key reaction parameters affecting the yields were identified. The results clearly indicate that the reaction parameters necessary to achieve high yields are substrate-dependent. In addition, it is demonstrated that aqueous Suzuki reactions of substrates containing basic nitrogen centers can produce quantitative yields of desired products in the absence of added ligand.

http://pubs.acs.org/doi/abs/10.1021/acs.oprd.6b00180
//////////
Mastoparan, Peptide (H-INLKALAALAKKIL-NH2)
H-Ile-Asn-Leu-Lys-Ala-Leu-Ala-Ala-Leu-Ala-Lys-Lys-xiIle-Leu-NH2
PEPTIDE1{I.N.L.K.A.L.A.A.L.A.K.K.[*N[C@H](C(=O)*)C(C)CC |$_R1;;;;;_R2;;;;$|].L.[am]}$$$$

| Ile – Asn – Leu – Lys – Ala – Leu – Ala – Ala – Leu – Ala – Lys – Lys – Ile – Leu -NH2 |
| Mastoparan; Mast cell degranulating peptide (Vespula lewisii); NSC351907; CAS 72093-21-1; | |
| Molecular Formula: | C70H131N19O15 |
|---|---|
| Molecular Weight: | 1478.90744 g/mol |
Description
| Physical State: | Solid |
| Derived from: | Synthetic. Originally isolated from wasp venom (Vespula lewisii) |
| Solubility: | Soluble in water (2.6 mg/ml), and 100% ethanol. |
| Storage: | Store at -20° C |
| Refractive Index: | n20D 1.53 |
| IC50: | Na+,K+-ATPase: IC50 = 7.5 µM |
Mastoparan is a peptide toxin from wasp venom. It has the chemical structure Ile-Asn-Leu-Lys-Ala-Leu-Ala-Ala-Leu-Ala-Lys-Lys-Ile-Leu-NH2.[2]
The net effect of mastoparan’s mode of action depends on cell type, but seemingly always involves exocytosis. In mast cells, this takes the form of histamine secretion, while in platelets and chromaffin cells release serotonin and catecholamines are found, respectively. Mastoparan activity in the anterior pituitary gland leads to prolactin release.
In the case of histamine secretion, the effect of mastoparan takes place via its interference with G protein activity. By stimulating theGTPase activity of certain subunits, mastoparan shortens the lifespan of active G protein. At the same time, it promotes dissociation of any bound GDP from the protein, enhancing GTP binding. In effect, the GTP turnover of G proteins is greatly increased by mastoparan. These properties of the toxin follow from the fact that it structurally resembles activated G protein receptors when placed in a phospholipid environment. The resultant G protein-mediated signaling cascade leads to intracellular IP3 release and the resultant influx of Ca2+.
In an experimental study conducted by Tsutomu Higashijima and his counterparts, mastoparan was compared to melittin, which is found in bee venom.[2] Mainly, the structure and reaction to phosphate was studied in each toxin. Using Circular Dichroism (CD), it was found that when mastoparan was exposed to methanol, an alpha helical form existed. It was concluded that strong intramolecular hydrogen bonding occurred. Also, two negative bands were present on the CD spectrum. In an aqueous environment, mastoparan took on a nonhelical, unordered form. In this case, only one negative band was observed on the CD spectrum. Adding phosphate buffer to mastoparan resulted in no effect.
Melittin produced a different conformational change than mastoparan. In an aqueous solution, melittin went from a nonhelical form to an alpha helix when phosphate was added to the solution. The binding of melittin to the membrane was believed to result fromelectrostatic interactions, not hydrophobic interactions.
Infections caused by multidrug resistant bacteria are currently an important problem worldwide. Taking into account data recently published by the WHO, lower respiratory infections are the third cause of death in the world with around 3.2 million deaths per year, this number being higher compared to that related to AIDS or diabetes mellitus [1]. It is therefore important to solve this issue, although the perspectives for the future are not very optimistic. During the last 30 years an enormous increase has been observed of superbugs isolated in the clinical setting, especially from the group called ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp.) which show high resistance to all the antibacterial agents available [2]. We will focus on Acinetobacter baumannii, the pathogen colloquially called “iraquibacter” for its emergence in the Iraq war. It is a Gram-negative cocobacillus and normally affects people with a compromised immune system, such as patients in the intensive care unit (ICU) [3] and [4]. Together with Escherichia coliand P. aeruginosa, A. baumannii are the most common cause of nosocomial infections among Gram-negative bacilli. The options to treat infections caused by this pathogen are diminishing since pan-drug resistant strains (strains resistant to all the antibacterial agents) have been isolated in several hospitals [5]. The last option to treat these infections is colistin, which has been used in spite of its nephrotoxic effects [6]. The evolution of the resistance of A. baumannii clinical isolates has been established by comparing studies performed over different years, with the percentage of resistance to imipenem being 3% in 1993 increasing up to 70% in 2007. The same effect was observed with quinolones, with an increase from 30 to 97% over the same period of time[7]. In Spain the same evolution has been observed with carbapenems; in 2001 the percentage of resistance was around 45%, rising to more than 80% 10 years later [8]. Taking this scenario into account, there is an urgent need for new options to fight against this pathogen. One possible option is the use of antimicrobial peptides (AMPs) [9],[10] and [11], and especially peptides isolated from a natural source [12]. One of the main drawbacks of using peptides as antimicrobial agents is the low stability or half-life in human serum due to the action of peptidases and proteases present in the human body[13], however there are several ways to increase their stability, such as using fluorinated peptides [14] and [15]. One way to circumvent this effect is to study the susceptible points of the peptide and try to enhance the stability by protecting the most protease labile amide bonds, while at the same time maintaining the activity of the original compound. Another point regarding the use of antimicrobial peptides is the mechanism of action. There are several mechanisms of action for the antimicrobial peptides, although the global positive charge of most of the peptides leads to a mechanism of action involving the membrane of the bacteria [16]. AMPs has the ability to defeat bacteria creating pores into the membrane [17], also acting as detergents [18], or by the carpet mechanism [19]. We have previously reported the activity of different peptides against colistin-susceptible and colistin-resistant A. baumannii clinical isolates, showing that mastoparan, a wasp generated peptide (H-INLKALAALAKKIL-NH2), has good in vitro activity against both colistin-susceptible and colistin-resistant A. baumannii [20]. Therefore, the aim of this manuscript was to study the stability of mastoparan and some of its analogues as well as elucidate the mechanism of action of these peptides.
Paper
Volume 101, 28 August 2015, Pages 34–40
http://www.sciencedirect.com/science/article/pii/S0223523415300933
doi:10.1016/j.ejmech.2015.06.016
The treatment of some infectious diseases can currently be very challenging since the spread of multi-, extended- or pan-resistant bacteria has considerably increased over time. On the other hand, the number of new antibiotics approved by the FDA has decreased drastically over the last 30 years. The main objective of this study was to investigate the activity of wasp peptides, specifically mastoparan and some of its derivatives against extended-resistant Acinetobacter baumannii. We optimized the stability of mastoparan in human serum since the specie obtained after the action of the enzymes present in human serum is not active. Thus, 10 derivatives of mastoparan were synthetized. Mastoparan analogues (guanidilated at the N-terminal, enantiomeric version and mastoparan with an extra positive charge at the C-terminal) showed the same activity against Acinetobacter baumannii as the original peptide (2.7 μM) and maintained their stability to more than 24 h in the presence of human serum compared to the original compound. The mechanism of action of all the peptides was carried out using a leakage assay. It was shown that mastoparan and the abovementioned analogues were those that released more carboxyfluorescein. In addition, the effect of mastoparan and its enantiomer against A. baumannii was studied using transmission electron microscopy (TEM). These results suggested that several analogues of mastoparan could be good candidates in the battle against highly resistant A. baumannii infections since they showed good activity and high stability.
Patent IDDatePatent TitleUS20160672612016-03-10SERCA INHIBITOR AND CALMODULIN ANTAGONIST COMBINATION
| Mastoparan | |
|---|---|
Solution structure of mastoparan from Vespa simillima xanthoptera.[1]
|
|
| Identifiers | |
| Symbol | Mastoparan_2 |
| Pfam | PF08251 |
| InterPro | IPR013214 |
| TCDB | 1.C.32 |
| OPM superfamily | 160 |
| OPM protein | 2czp |
///////Peptide, Antimicrobial peptide, Mastoparan, Acinetobacter baumannii, NSC351907, 72093-21-1, NSC 351907
CCC(C)C(C(=O)NC(CC(=O)N)C(=O)NC(CC(C)C)C(=O)NC(CCCCN)C(=O)NC(C)C(=O)NC(CC(C)C)C(=O)NC(C)C(=O)NC(C)C(=O)NC(CC(C)C)C(=O)NC(C)C(=O)NC(CCCCN)C(=O)NC(CCCCN)C(=O)NC(C(C)CC)C(=O)NC(CC(C)C)C(=O)N)N
Cas 1929605-82-2

SYNTHESIS
Scheme .
Synthetic strategy used in the synthesis of 52. Reagents and conditions: (a) NaH (1 equiv.), THF, 0 °C to RT, 3 h; (b) KCN (1.2 equiv.), 25% H2SO4, 0 °C to RT, 20 h; c) HCl, AcOH, reflux, 24 h; (d) 8, SOCl2(1.3 equiv.), DMA, RT, 72 h.
3-Bromo-1,1,1-trifluoroacetone (48) was coupled with thiophenol 47 to afford 49, which was then converted into cyano derivative 50 using potassium cyanide and 25% sulfuric acid [16]. Intermediate 51 was obtained after refluxing 50 in concentrated HCl and glacial acetic acid. Coupling of 51 with commercially available 4-nitro-3-(trifluoromethyl)aniline 8yielded the desired amide 52.
To a mixture of NaH (10.47 mmol) in 10 mL anhydrous THF was added a solution of 2-(trifluoromethyl)benzenethiol (10.47 mmol) in 2mL anhydrous THF at 0 °C. This mixture was stirred for 20 min. 3-Bromo-1,1,1-trifluoropropan-2-one was then added dropwise to the mixture at 0 °C, the reaction was warmed to r.t. and stirred for 12 h. The mixture was filtered trough celite, the filtered pad was washed with THF, and the filtrate was evaporated to dryness. The residue was purified by flash column chromatography eluting with n-hexane/EtOAc 100:0 v/v increasing to n-hexane/EtOAc 85:15 v/v to give a pale yellow oil in 93% yield. 1H-NMR (CDCl3): d 7.76-7.69 (m, 2H), 7.60-7.53 (m, 1H), 7.42-7.38 (m, 1H), 3.44 (s, 2H). 19F-NMR (CDCl3): d -59.91 (s, 3F), -85.26 (s, 3F). 13C-NMR (CDCl3): d 189.6, 137.7, 135.9, 134.5, 133.2, 130.6, 129.6 (q, J= 26.3 Hz), 127.0 (q, J= 3.8 Hz), 124.3 (q, J= 4.1 Hz), 124.0 (q, J= 3.7 Hz), 94.4 (q, J= 30.4 Hz), 40.4.
A 20% aqueous solution of H2SO4 (3.4 mL) was added dropwise to a mixture of 49 (11.03 mmol) and KCN (13.24 mmol) in 5 mL H2O at 0 °C. The reaction mixture was warmed to r.t. and stirred for 20 h. The mixture was then diluted with water (50 mL) and extracted with Et2O (3 x 150 mL). The organic extracts were washed with sat. aq. NaHCO3 and brine, dried over Na2SO4 and concentrated in vacuo. The residue was purified by flash column chromatography eluting with n-hexane/EtOAc 100:0 v/v increasing to n-hexane/EtOAc 95:5 v/v to give a pale yellow oil in 86% yield. 1H-NMR (CDCl3): d 7.80 (d, J= 7.8 Hz, 1H), 7.77-7.76 (m, 1H), 7.72-7.59 (m, 1H), 7.52-7.49 (m, 1H), 4.36 (bs, 1H), 3.58 (d, J= 14.6 Hz, 1H), 3.44 (d, J= 14.6 Hz, 1H). 19F-NMR (CDCl3): d -57.08 (s, 3F), -79.51 (s, 3F). 13C-NMR (CDCl3): d 135.4, 132.8, 132.5 (q, J= 30.1 Hz), 129.1, 128.7 (q, J= 5.5 Hz), 126.7, 124.9, 124.6, 122.6, 122.4, 120.4, 114.0, 71.4 (q, J= 32.9), 40.75.
A mixture of 51 (6.89 mmol), concentrated HCl (23.4 mL) and AcOH (4.1 mL) was refluxed o.n. with vigorous stirring. The mixture was then diluted with water (100 mL) and extracted with Et2O (4 x 100 mL), which was in turn washed with sat. aq. NaHCO3 (4 x 100 mL). The water solution was acidified with concentrated HCl to pH 1 and extracted with Et2O (4x 150 mL). The Et2O extracts were dried over Na2SO4, filtered and concentrated to dryness to give a pale yellow waxy solid in 41% yield. 1H-NMR (CDCl3): d 9.57 (bs, 1H), 7.70 (d, J= 7.7 Hz, 1H), 7.67 (d, J= 7.7 Hz, 1H), 7.54-7.51 (m, 1H), 7.39-7.36 (m, 1H), 3.60 (s, 2H). 19F-NMR (CDCl3): d -60.10 (s, 3F), -77.7 (s, 3F). 13C-NMR (CDCl3): d 172.0, 134.1, 134.0, 131.2 (q, J= 30.1 Hz), 127.5, 126.7 (q, J= 5.6 Hz), 124.2 (q, J= 121.9 Hz), 121.9 (q, J= 126.7 Hz), 78.2 (q, J= 28.7 Hz), 37.7.
Thionyl chloride (1.16 mmol) was added dropwise to a stirring solution of 51 in anhydrous DMA at -10 °C under Ar atmosphere. The reaction mixture was stirred for 1 h, then a solution of 8 in 2 mL anhydrous DMA was added dropwise. The reaction mixture was warmed to r.t. and stirred for 72 h. The mixture was then diluted with sat. aq. NaHCO3 (40 mL) and extracted with Et2O (3 x 40 mL). The organic extracts were filtered trough celite, dried over Na2SO4 and evaporated to dryness. The residue was purified by flash column chromatography eluting with n-hexane/EtOAc 100:0 v/v increasing to n-hexane/EtOAc 80:20 v/v to give a pale yellow solid in 13% yield.
1H-NMR (CDCl3): d 8.93 (bs, 1H), 7.94 (d, J= 8.8 Hz, 1H), 7.87 (d, J= 2.2 Hz, 1H), 7.72 (d, J= 8.1 Hz, 1H), 7.69 (dd, J= 8.8 Hz, 2.2 Hz, 1H), 7.50-7.47 (m, 2H), 7.26-7.23 (m, 1H), 4.41 (s, 1H), 4.19 (d, 14.7 Hz, 1H), 3.45 (d, J= 14.7 Hz, 1H).
19F-NMR (CDCl3): d -59.7 (s, 3F), -60.12 (s, 3F), -77.4 (s, 3F).
13C-NMR (CDCl3): d 164.6, 143.8, 140.0, 134.7, 132.6, 131.1 (q, J= 29.8 Hz), 130.5, 128.3, 126.8 (q, J= 5.5 Hz), 126.7, 125.2 (q, J= 36.3 Hz), 124.5, 123.9, 122.6, 122.4, 122.2, 121.7, 120.4, 118.2 (q, J= 5.8 Hz), 76.3 (q, J= 27.8 Hz), 38.5.
MS [ESI, m/z]: 523.0 [M+H]+.
EI-HMRS (M-H)– found 521.0215, calculated for C18H0N2O4F9S 521.0218.
HPLC (method 1): retention time = 23.84 min.
clips
Prostate cancer (PC) is a leading cause of male death worldwide and it is the most frequently diagnosed cancer among men aged 65–74 [1]. The prognosis varies greatly, being highly dependent on a number of factors such as stage of diagnosis, race and age. Currently, PC treatment includes androgen deprivation, surgery, radiation, endocrine therapy and radical prostatectomy.
PC cell growth is strongly dependent on androgens, therefore blocking their effect can be beneficial to the patient’s health. Such outcomes can be achieved by antagonism of the androgen receptor (AR) using anti-androgen drugs, which have been extensively explored either alone or in combination with castration [2]. Flutamide (Eulexin®) (1) (in its active form as hydroxyflutamide (2)), bicalutamide (Casodex®) (3), nilutamide (Niladron®) (4) and enzalutamide (previously called MDV3100) (Xtandi®) (5) are all non-steroidal androgen receptor antagonists approved for the treatment of PC (Fig. 1). In many cases, after extended treatment over several years, these anti-androgens become ineffective and the disease may progress to a more aggressive and lethal form, known as castration resistant prostate cancer (CRPC). The major cause of this progressive disease is the emergence of different mutations on the AR, which cause the anti-androgen compounds to function as agonists, making them tumour-stimulating agents[3].
Among the drugs used for the treatment of PC, bicalutamide and enzalutamide selectively block the action of androgens while presenting fewer side effects in comparison with other AR antagonists [4], [5] and [6]. The structure of these molecules is characterised by the presence of a trifluoromethyl substituted anilide, which appears to be critical for biological activity (Fig. 1). As a means to improve the anti-proliferative activity of these compounds, and in order to exploit the well established potential of the fluorine atom in enhancing the pharmacological properties and drug-like physicochemical characteristics of candidate compounds [7], [8] and [9], a wide array of diverse new structures has been rationally designed and synthesised, through the introduction of fluoro-, trifluoromethyl- and trifluoromethoxy groups in diverse positions of both aromatic rings of the parent scaffolds. Our modifications resulted in a marked improvement of in vitro anti-proliferative activities on a range of human PC cell lines (VCap, LNCaP, DU-145 and 22RV1). In addition, we probed full versus partial AR antagonism for our new compounds.
Paper

Volume 118, 8 August 2016, Pages 230–243
School of Pharmacy and Pharmaceutical Sciences, Redwood Building, King Edward VII Avenue, CF10 3NB, Cardiff, Wales, UK
Prostate cancer (PC) is one of the major causes of male death worldwide and the development of new and more potent anti-PC compounds is a constant requirement. Among the current treatments, (R)-bicalutamide and enzalutamide are non-steroidal androgen receptor antagonist drugs approved also in the case of castration-resistant forms. Both these drugs present a moderate antiproliferative activity and their use is limited due to the development of resistant mutants of their biological target.
Insertion of fluorinated and perfluorinated groups in biologically active compounds is a current trend in medicinal chemistry, applied to improve their efficacy and stability profiles. As a means to obtain such effects, different modifications with perfluoro groups were rationally designed on the bicalutamide and enzalutamide structures, leading to the synthesis of a series of new antiproliferative compounds. Several new analogues displayed improved in vitro activity towards four different prostate cancer cell lines, while maintaining full AR antagonism and therefore representing promising leads for further development.
Furthermore, a series of molecular modelling studies were performed on the AR antagonist conformation, providing useful insights on potential protein-ligand interactions.
http://www.sciencedirect.com/science/article/pii/S0223523416303452

Professor Chris McGuigan, 57, was trying to invent new drugs to use in the fight against the disease.
But the tragic scientist, who was head of medicinal chemistry at Cardiff University’s School of Pharmacy and Pharmaceutical Sciences, died after his own fight with cancer.
A spokesman for Cardiff University said: “Professor McGuigan had been at the heart of scientific research for more than 30 years. He was an exceptionally gifted inventor and chemist.
“His loss will be felt cross the university and the wider scientific community.

“He had a strong drive to use his scientific ideas for social good, working tirelessly to address medical needs where they were unmet.
“Our thoughts are with his family, friends and close colleagues at this very sad time.”
Prof McGuigan’s research led him to try and develop new drugs for cancer, HIV, hepatitis B and C, shingles, measles, influenza and central nervous system (CNS) disease.
He also invented four new experimental drugs that were used in human clinical trials.
Prof McGuigan, who lived in Cardiff, is survived by wife Maria, 50, and his two young daughters Phoebe and Grace.
///////////1929605-82-2, bicalutamide and enzalutamide derivatives, antiproliferative agents, treatment of prostate cancer, School of Pharmacy and Pharmaceutical Sciences, Redwood Building, King Edward VII Avenue, CF10 3NB, Cardiff, Wales, UK
FC(F)(F)c1cc(ccc1[N+]([O-])=O)NC(=O)C(O)(CSc2ccccc2C(F)(F)F)C(F)(F)F

PHASE 1 CHINA



The main purpose: to determine HAO472 treatment of relapsed / refractory C the maximum tolerated dose (MTD). Secondary objectives: 1) evaluation of drug safety and tolerability; 2) study HAO472 in pharmacokinetic characteristics of the human body; 3) the effectiveness of HAO472 treatment of relapsed / refractory M2b type of AML.
Acute myelogenous leukemia
HAO472
Phase I
Test Number: CTR20150246
Sponsor Name:
Jiangsu Hengrui Medicine Co., Ltd. 1/
2 Ruijin Hospital, Shanghai Jiaotong University School of Medicine /
3 Jiangsu Hengrui Medicine Co., Ltd. /
4 Shanghai Hengrui Medicine Co., Ltd. /

Natural products have historically been, and continue to be, an invaluable source for the discovery of various therapeutic agents. Oridonin, a natural diterpenoid widely applied in traditional Chinese medicines, exhibits a broad range of biological effects including anticancer and anti-inflammatory activities. To further improve its potency, aqueous solubility and bioavailability, the oridonin template serves as an exciting platform for drug discovery to yield better candidates with unique targets and enhanced drug properties. A number of oridonin derivatives (e.g. HAO472) have been designed and synthesized, and have contributed to substantial progress in the identification of new agents and relevant molecular mechanistic studies toward the treatment of human cancers and other diseases. This review summarizes the recent advances in medicinal chemistry on the explorations of novel oridonin analogues as potential anticancer therapeutics, and provides a detailed discussion of future directions for the development and progression of this class of molecules into the clinic.
Volume 122, 21 October 2016, Pages 102–117

////////Natural product, Oridonin, Diterpenoids, Anticancer agents, Drug discovery, Chemical biology, AML, HAO 472, relapsed / refractory AML. Jiangsu Hengrui Medicine Co., Ltd, PHASE1, LEUKEMIA
C[C@H](N)C(=O)O[C@]15OC[C@@]2([C@H](O)CCC(C)(C)[C@@H]2[C@H]1O)[C@H]3CC[C@@H]4C(=C)C(=O)[C@@]35C4O
![]()
Eldecalcitol
(1S,2S,3S,5Z)-5-[(2E)-2-[(1R,3aS,7aR)-1-[(2R)-6-hydroxy-6-methylheptan-2-yl]-7a-methyl-2,3,3a,5,6,7-hexahydro-1H-inden-4-ylidene]ethylidene]-2-(3-hydroxypropoxy)-4-methylidenecyclohexane-1,3-diol
(1R,2R,3R,5Z,7E)-2-(3-Hydroxypropyloxy)-9,10-secocholesta-5,7,10(19)-triene-1,3,25-triol
| AC1O5QQ2; CAS 104121-92-8; AN-3697; ED 71, Edirol® | |
| Molecular Formula: | C30H50O5 |
|---|---|
| Molecular Weight: | 490.715 g/mol |
APPROVED JAPAN , 2011-01-21, Chugai (Originator) , Roche,Taisho Toyama
Eldecalcitol was approved by Pharmaceuticals and Medicals Devices Agency of Japan (PMDA) on January 21, 2011. It was developed by Chugai Pharmaceutical (a member of Roche) and marketed as Edirol® by Chugai Pharmaceutical and Taisho.
Eldecalcitol is an orally active vitamin D analogue leading to greater absorption of bind calcium. It is usually used to treat osteoporosis.
Edirol® is available as capsule for oral use, containing 0.5 μg or 0.75 μg of free Eldecalcitol, and the recommended dose is 0.75 μg once daily.
ED-71, a vitamin D analog, is a more potent inhibitor of bone resorption than alfacalcidol in an estrogen-deficient rat model of osteoporosis. ED-71, effectively and safely increased lumbar and hip bone mineral density (BMD) in osteoporotic patients who also received vitamin D3 supplementation.
Eldecalcitol is a drug used in Japan for the treatment of osteoporosis.[1] It is an analog of vitamin D.[2] Osteoporosis is a common bone disease among the older generation, with an estimated prevalence of over 200 million people.[1] This condition often results in bone fractures due to abnormally low bone mass density, and is a leading cause of disability, especially among developed countries with longer average life spans. Osteoporosis is more common in women than with men.
Eldecalcitol
Chugai Pharmaceutical/Roche are the originators of the medicinal drug eldecalcitol through Taisho Pharmaceutical Holdings and Chugai Pharmaceutical. The trade name of eldecalcitol is Edirol, and its Chemical Abstracts Service (CAS) registry number is 104121-92-8. Eldecalcitol was approved for use in Japan on January 2011. The approval came from the Japanese Ministry of Health, Labor, and Welfare for the objective of a treatment for osteoporosis.[3]
Clinical trials have suggested that eldecalcitol, a vitamin D analog, has strong effects to reduce calcium reabsorption into the body from bones, therefore increasing bone mineral density, and to increase calcium absorption in intestines.[4] In animals, eldecalcitol inhibits the activity of osteoclasts for the function to reduce bone degradation for calcium, while still able to maintain osteoblast function so as to not hinder bone formation.[5] Unlike other vitamin D analogs, eldecalcitol does not significantly suppress parathyroid hormone levels, promising a better treatment for osteoporosis in comparison to other medications.[6] Bone mineral density increases with eldecalcitol use, in addition to strengthening bone structure. This occurs due to the function of the eldecalcitol drug, which decreases bone reabsorption as observed through a bone reabsorption marker. Bone geometry assessments show that eldecalcitol increases cortical bone area in patients with osteoporosis more so than other vitamin D analogs, such as alfacalcidol. There was also the maintenance of thickness of cortical bone mass, strongly indicating that eldecalcitol improves the strength and mass of bone, specifically cortical bone structure.[7] Adverse effects of eldecalcitol include an increase in blood and urinary calcium levels. Abnormally high levels of calcium can lead to problems associated with hypercalcemia.
Eldecalcitol can be used for the treatment of hypocalcaemia or osteoporosis. Calcium absorption increases with the presence of eldecalcitol by the body, occurring in the intestines, which is useful for those who have low calcium levels. Eldecalcitol is more often used due to its effects to treat osteoporosis. In the aging population, the bone matrix becomes weakened through untreated osteoporosis. This leads to an increased risk of severe fractures that include spinal and hip fractures in addition to vertebral and wrist fractures. This creates a burden on the health care system due to a decline in the quality of life for the individuals that suffer from this condition. Some risk factors leading to the predisposition of developing osteoporosis are previous incidents of bone fractures and a reduction in bone mineral density.[1] These factors expectantly increase as age increases. Bone health is reliant on maintaining physiologically needed levels of calcium, where the body constantly maintains this calcium homeostasis through osteoblast and osteoclast activity. Osteoblast activity serves this function of maintaining appropriate calcium levels by depositing calcium in bones when blood calcium levels are above normal. In contrast, osteoclasts break down bone tissue to increase blood calcium levels if they are low.[8] This activity is performed after absorption of calcium by the body, which requires the actions of vitamin D. The active metabolite of vitamin D, calcitriol, performs its function through interactions with the calcitriol receptor. This nuclear hormone receptor is responsible for calcium absorption which, in turn, is involving in bone depletion and formation. The new analogs of vitamin D, such as eldecalcitol, are observed to have stronger effects in preventing bone loss, fractures, and falls in comparison to calcitriol.[9] Eldecalcitol is even more effective than its counterpart alfacalcidol, another vitamin D analog. Studies have shown eldecalcitol is more effective than alfacalcidol in preventing vertebral and wrist fractures, and even falls, with osteoporotic patients with vitamin D insufficiencies.[10] Eldecalcitol is also more effective at preventing fractures than vitamin D and calcium supplements.[1] Eldecalcitol increases calcium absorption for vitamin D deficient patients, and therefore could be used for osteoporosis treatment for all age groups.
Analogs of vitamin D are being explored intensely for their regulatory effects on calcium metabolism with the purpose of treating osteoporosis, a skeletal disease associated with low bone mass and deterioration of bone tissue. Vitamin D is imperative for absorption of calcium to maintain bone strength.
Eldecalcitol is an orally administered drug to patients, which binds to vitamin D receptors and binding protein for the goal of achieving greater specificity to bind calcium for its absorption. This greater affinity is 2.7-fold that of the active vitamin D form of calcitriol. Eldecalcitol is readily absorbed into the body, with a long elimination half-life of over eight hours, reaching maximum absorption in 3.4 hours.[1]
Eldecalcitol is present in the form of pills for oral administration. In preclinical models with healthy male volunteers, oral doses of eldecalcitol ranged from 0.1 to 1.0 micrograms once daily to show an increase in bone mineral density.[11] Preclinical trials show improvements for doses at 0.5 and 0.75 micrograms, which are the recommended dosage amounts for the Edirol product as approved by the Japanese Ministry of Health, Labor, and Welfare for treating osteoporosis.[3]
The class of eldecalcitol is a vitamin D3 derivative. This molecule has a molecular weight of 490.71 grams per mole. The eldecalcitol analog of calcitriol, contains a hydroxypropyl group in the lower cyclohexane ring. The synthesis of eldecalcitol incorporates two units assembled together. The IUPAC names include (3S, 4S, 5R)-oct-1-en-7-yne-3,4,5-triol that is fused to a bicyclic system, (R)-6-((1R, 3aR, 7aR, E)-4-(bromomethylene)-7a-methyloctahydro-1H-inden-1-yl)-2-methylheptan-2-ol. The assembly process includes a Diels-Alder reaction to give the fully protected eldecalcitol. In order to get the parent molecule, the hydroxyl groups have to be deprotected. The chemistry of eldecalcitol allows for its binding 2.7-fold more potently than calcitriol. In addition, some vitamin D derivatives have been known to inhibit the serum parathyroid hormone. Eldecalcitol only weakly inhibits the serum parathyroid hormone, making it an even more appealing medicinal drug for its physiological uses in the treatment of osteoporosis.[3] Animal studies of eldecalcitol, in ovariectomized rats, show improvements in bone mass while lowering bone reabsorption to demonstrate its effectiveness in osteoporosis treatment.[5]
PAPER
Heterocycles, Vol 92, No. 6, 2016, pp.1013-1029
Published online, 22nd March, 2016
Noboru Kubodera*
*International Institute of Active Vitamin D Analogs, 35-6, Sankeidai, Mishima, Shizuoka 411-0017, Japan
Presented herein are diverse and important contributions by medicinal chemists to different stages of pharmaceutical development. The conceptual elements reviewed, which are intended for young chemists who engage in drug discovery research, draw upon the author’s experience in developing eldecalcitol, an active vitamin D3 analog used to treat osteoporosis. The review covers exploratory research for a lead candidate compound; process development for practical manufacturing; and synthesis of other compounds relevant to the program, such as tritiated compounds, postulated metabolites, and miscellaneous analogs for mode of action studies.
PAPER
Eldecalcitol [1α,25-dihydroxy-2β-(3-hydroxypropoxy)vitamin D3], an analog of calcitriol (1α,25-dihydroxyvitamin D3), possesses a hydroxypropoxy substituent at the 2β-position of calcitriol. Eldecalcitol has potent biological effects on bone disease such as osteoporosis. The marketing of eldecalcitol has very recently started in Japan. In consideration of this, we have been investigating practical synthesis of eldecalcitol for industrial-scale production. Eldecalcitol was initially synthesized in a linear manner. The 27-step linear sequence was, however, suboptimal due to its lengthiness and low overall yield (ca. 0.03%). Next, we developed a convergent approach based on the Trost coupling reaction, in which the A-ring fragment (ene-yne part obtained in 10.4% overall yield) and the C/D-ring fragment (bromomethylene part obtained in 27.1% overall yield) are coupled to produce the triene system of eldecalcitol (15.6%). Although the overall yield of the convergent synthesis was better than that of the linear synthesis, significant improvements were still necessary. Therefore, additional biomimetic studies were investigated. Process development for the practical production of eldecalcitol is described herein.
http://ar.iiarjournals.org/content/32/1/303/F3.expansion.html
Convergent synthesis of eldecalcitol (5) by coupling A-ring fragment 37 with C/D-ring fragment 40. Reagents and conditions: a: HO(CH2)3OH/t-BuOK, 120°C. b: t-BuCOCl/pyridine/CH2Cl2, rt. c: H2/Pd(OH)2/MeOH, rt. d: Me2C(OMe)2/TsOH/acetone, rt. e: DMSO/(COCl)2/CH2Cl2, −60°C. f: CH2=CHMgBr/THF, −60°C. g: t-BuCOCl/Et3N/DMAP/CH2Cl2, rt. h: 1 M HCl/MeOH, rt. i: Ph3P/DEAD/benzene, reflux. j: LiC ≡ CTMS/BF3-OEt2, −78°C. k: 10 N NaOH/MeOH, rt. l: TBSOTf/Et3N/CH2Cl2, 0°C. m: TESOTf/Et3N/CH2Cl2, 0°C. n: O3/CH2Cl2/MeOH, −78°C then NaBH4/MeOH, −78°C. o: NMO/TPAP/4Ams/CH2Cl2, rt. p: Ph3P+CH2BrBr−/NaHMDS/ THF, −60°C to rt. q: (dba)3Pd2-CHCl3/PPh3/Et3N/toluene, reflux. r: TBAF/THF/toluene, reflux.

Industrial synthesis of alfacalcidol (4) and biomimetic synthesis of eldecalcitol (5) from cholesterol (42). Reagents and conditions: a: [Al(Oi-Pr)3]/cyclohexanone. b: DDQ/AcOEt. c: NaOEt/EtOH. d: NaBH4/MeOH/THF. e: Ac2O/DMPA/pyridine, rt. f: NBS/AIBN/n-hexane, reflux. g: γ-collidine/toluene, reflux. h: KOH/MeOH, rt. i: PTAD/CH2Cl2, rt. j: TBSCl/imidazole. k: MCPBA/CH2Cl2. l: DMI, 140°C. m: TBAF/THF. n: NaBH4/EtOH. o: 400 W high pressure mercury lamp/THF, 0°C then reflux without mercury lamp. p: HO(CH2)3OH/t-BuOK, 110°C. q: Microbial 25-hydroxylation.

Reference:1. US4666634A / EP184206A2.
Reference:1. Anticancer. Res. 2012, 32, 303-310.
2. Drugs. Fut. 2005, 30, 450-461.
Reference:1. J. Am. Chem. Soc. 2001, 123, 3716-3722.
Reference:1. Bioorg. Med. Chem. Lett. 1997, 7, 2871-2874.
2. Anticance. Res. 2009, 29, 3571-3578.
| No. | Major Technical Classification | Publication No. | Patent No. | Legal Status | Filling Date | Estimated Expiry Date |
| 1 | Preparation | CN85108857A | CN1008368B | Granted/expired | 1985/12/4 | 2005/12/4 |
| 2 | Crystal | CN1223639A | CN1216861C | Granted | 1997/6/16 | 2017/6/16 |
| 3 | Preparation | CN1637017A | CN1276927C |
| Patent ID | Date | Patent Title |
|---|---|---|
| US7927613 | 2011-04-19 | Pharmaceutical co-crystal compositions |
| US7323580 | 2008-01-29 | CRYSTALS OF A VITAMIN D DERIVATIVE AND A METHOD FOR THE PREPARATION THEREOF |
| US7235679 | 2007-06-26 | Crystals of a vitamin D derivative and a method for the preparation thereof |
| EP0924199 | 2006-05-10 | CRYSTALS OF VITAMIN D DERIVATIVES AND PROCESS FOR THE PREPARATION THEREOF |
| US2005009794 | 2005-01-13 | Crystals of a vitamin D derivative and a method for the preparation thereof |
| US6831183 | 2004-12-14 | Crystals of a vitamin D derivative and a method for the preparation thereof |
| US6448421 | 2002-09-10 | CRYSTALS OF VITAMIN D DERIVATIVES AND PROCESS FOR THE PREPARATION THEREOF |
| Systematic (IUPAC) name | |
|---|---|
|
(1S,2S,3S,5Z,7E)-2-(3-Hydroxypropoxy)-9,10-secocholesta-5,7,10-triene-1,3,25-triol
|
|
| Clinical data | |
| Trade names | Edirol |
| Identifiers | |
| CAS Number | 104121-92-8 |
| ATC code | None |
| PubChem | CID 6438982 |
| ChemSpider | 4943418 |
| Chemical data | |
| Formula | C30H50O5 |
| Molar mass | 490.715 g/mol |
///////////eldecalcitol, active vitamin D3 analog, treat osteoporosis, AC1O5QQ2, 104121-92-8, AN-3697, ED 71, ED-71, Edirol®, PMDA, JAPAN
O[C@H]1CC(\C(=C)[C@H](O)[C@H]1OCCCO)=C\C=C2/CCC[C@]3([C@H]2CC[C@@H]3[C@H](C)CCCC(O)(C)C)C
OR
CC(CCCC(C)(C)O)C1CCC2C1(CCCC2=CC=C3CC(C(C(C3=C)O)OCCCO)O)C

Rifaximin;
Rifaxidin; Rifacol; Xifaxan; Normix; Rifamycin L 105;L 105 (ansamacrolide antibiotic), L 105SV
(2S,16Z,18E,20S,21S,22R,23R,24R,25S,26S,27S,28E)-5,6,21,23,25-pentahydroxy-27-methoxy-2,4,11,16,20,22,24,26-octamethyl-2,7-(epoxypentadeca-[1,11,13]trienimino)benzofuro[4,5-e]pyrido[1,2-á]-benzimidazole-1,15(2H)-dione,25-acetate
CAS 80621-81-4, 4-Deoxy-4-methylpyrido[1,2-1,2]imidazo[5,4-c]rifamycin SV,
4-Deoxy-4′-methylpyrido[1′,2′-1,2]imidazo[5,4-c]rifamycin SV, Rifacol
| C43H51N3O11 | |
| Molecular Weight: | 785.87854 g/mol |
|---|

XIFAXAN tablets for oral administration are film-coated and contain 200 mg or 550 mg of rifaximin.
Rifaximin is an orally administered, semi-synthetic, nonsystemic antibiotic derived from rifamycin SV with antibacterial activity. Rifaximin binds to the beta-subunit of bacterial DNA-dependent RNA polymerase, inhibiting bacterial RNA synthesis and bacterial cell growth. As rifaximin is not well absorbed, its antibacterial activity is largely localized to the gastrointestinal tract.
Rifaximin (trade names:RCIFAX, Rifagut, Xifaxan, Zaxine) is a semisynthetic antibiotic based on rifamycin. It has poor oral bioavailability, meaning that very little of the drug will be absorbed into the blood stream when it is taken orally. Rifaximin is used in the treatment of traveler’s diarrhea, irritable bowel syndrome, and hepatic encephalopathy, for which it receivedorphan drug status from the U.S. Food and Drug Administration in 1998.
Rifaximin is licensed by the U.S. Food and Drug Administration to treat traveler’s diarrhea caused by E. coli.[1] Clinical trials have shown that rifaximin is highly effective at preventing and treating traveler’s diarrhea among travelers to Mexico, with fewside effects and low risk of developing antibiotic resistance.[2][3][4] It is not effective against Campylobacter jejuni, and there is no evidence of efficacy against Shigella or Salmonella species.
| Launched – 1988 | Alfa Wassermann | Infection, bacterial |
| Launched – 2004 | Salix | Traveler’s diarrhea |
| Launched – 2010 | Salix | Encephalopathy, hepatic |
| Launched – 2015 | Salix | Irritable bowel syndrome (Diarrhea predominant) |
| Launched | Alfa Wassermann Merck & Co. |
Hyperammonemia |
The drug is also at Salix in phase II trials for the treatment of Crohn’s disease. Alfa Wasserman is also conducting phase II trials for Crohn’s disease. The product was approved and launched in the U.S. for the maintenance of remission of hepatic encephalopathy in 2010. Mayo Clinic is conducting phase II clinical trials in the U.S. for the treatment of primary sclerosing cholangitis and the University of Hong Kong is also conducting Phase II trials for the treatment of functional dyspepsia.
It may be efficacious in relieving chronic functional symptoms of bloating and flatulence that are common in irritable bowel syndrome (IBS),[5][6] especially IBS-D.
In February 1998, Salix was granted orphan drug designation by the FDA for the use of rifaximin to treat hepatic encephalopathy. In 2009, a codevelopment agreement was established between Lupin and Salix in the U.S. for the development of a new formulation using Lupin’s bioadhesive drug delivery technology.
There was recentlya pilot-study done on the efficacy of rifaximin as a means of treatment for rosacea, according to the study, induced by the co-presence of small intestinal bacterial overgrowth.[7]
In the United States, rifaximin has orphan drug status for the treatment of hepatic encephalopathy.[8] Although high-quality evidence is still lacking, rifaximin appears to be as effective as or more effective than other available treatments for hepatic encephalopathy (such as lactulose), is better tolerated, and may work faster.[9] Hepatic encephalopathy is a debilitating condition for those with liver disease. Rifaximin is an oral medication taken twice daily that helps patients to avoid reoccurring hepatic encephalopathy. It has minimal side effects, prevents reoccurring encephalopathy and high patient satisfaction. Patients are more compliant and satisfied to take this medication than any other due to minimal side effects, prolong remission, and overall cost.[10] Rifaximin helps patients avoid multiple readmissions from hospitals along with less time missed from work as well. Rifaximin should be considered a standard prescribed medication for those whom have episodes of hepatic encephalopathy.
The drawbacks to rifaximin are increased cost and lack of robust clinical trials for HE without combination lactulose therapy.
Also treats hyperammonemia by eradicating ammoniagenic bacteria.
Rifaximin interferes with transcription by binding to the β-subunit of bacterial RNA polymerase.[11] This results in the blockage of the translocation step that normally follows the formation of the first phosphodiester bond, which occurs in the transcription process.[12]
Efficacy
A 2011 study in patients with IBS (sans constipation) indicated 11% showed benefits over a placebo.[13] The study was supported by Salix Pharmaceuticals, the patent holder.[13] A 2010 study in patients treated for Hepatic Cirrhosis with hospitalization involving Hepatic encephalopathy resulted in 22% of the rifaxmin treated group experiencing a breakthrough episode of Hepatic encephalopathy as compared to 46% of the placebo group. The majority patients were also receivingLactulose therapy for prevention of hepatic encephalopathy in addition to Rifaximin.[14] Rifaximin shows promising results, causing remission in up to 59% of people with Crohn’s disease and up to 76% of people with Ulcerative Colitis.[15]
In the United States, Salix Pharmaceuticals holds a US Patent for rifaximin and markets the drug under the name Xifaxan, available in tablets of 200 mg and 550 mg.[16][17] In addition to receiving FDA approval for traveler’s diarrhea and (marketing approved for)[17] hepatic encephalopathy, Xifaxan received FDA approval for IBS in May 2015.[18] No generic formulation is available in the US and none has appeared due to the fact that the FDA approval process was ongoing. If Xifaxan receives full FDA approval for hepatic encephalopathy it is likely that Salix will maintain marketing exclusivity and be protected from generic formulations until March 24, 2017.[17] Price quotes received on February 21, 2013 for Xifaxan 550 mg in the Denver Metro area were between $23.57 and $26.72 per tablet. A price quote received on June 24, 2016 for Xifaxan 550 mg was $31.37 per tablet.
Rifaximin is approved in 33 countries for GI disorders.[19][20] On August 13, 2013, Health Canada issued a Notice of Compliance to Salix Pharmaceuticals Inc. for the drug product Zaxine.[21] In India it is available under the brand names Ciboz and Xifapill.[
SPECTRA
LINK IS CLICK
APT 13C NMR RIFAXIMIN
1H NMR PARTIAL
IR
Direct infusion mass analysis ESI (+)
IH NMR
Synthesis
Rifaximin is a broad-spectrum antibiotic belonging to the family of Rifamycins and shows its antibacterial activity, in the gastrointestinal tract against localized bacteria that cause infectious diarrhoea, irritable bowel syndrome, small intestinal bacterial overgrowth, Crohn’s disease, and/or pancreatic insufficiency.
Rifaximin is sold under the brand name Xifaxan® in US for the treatment of Travellers’ diarrhoea and Hepatic Encephalopathy. The chemical name of Rifaximin is (2S , 16Z, 18E,20S ,21 S ,22R,23R,24R,25S ,26S ,27S ,28E)-5,6,21 ,23 ,25-pentahydroxy-27-methoxy-2,4,1 l,16,20,22,24,26-octamethyl-2,7(epoxypentadeca-[l,l l,13]trienimino) benzofuro[4,5-e]pyrido[l,2-a]-benzimidazole-l,15(2H)-dione,25-acetate and the molecular formula is G^HsiNsOn with a molecular weight of 785.9. The structural formula of Rifaximin is:

Formula I
Rifaximin was first described and claimed in Italian patent IT 1154655 and U.S. Pat. No.4,341,785. These patents disclose a process for the preparation of Rifaximin and a method for the crystallisation thereof. The process for the preparation of Rifaximin is as depicted in scheme I given below:

Scheme -I
U.S. Pat. No. 4,179,438 discloses a process for the preparation of 3-bromorifamycin S which comprises reaction of rifamycin S with at least two equivalents of bromine, per one mole of rifamycin S in the presence of at least one mole of pyridine per each equivalent of bromine and in the presence of ethanol, methanol or mixtures thereof with water at a
temperature not above the room temperature. The process is shown in the scheme given below:

Rifamycin S 3-Bromo-Rifamycin-S
U.S. Patent No.4,557, 866 discloses a process for one step synthesis of Rifaximin from Rifamycin O, which is shown in scheme II given below:

Rifamycin O Rifaximin
Scheme -II
US ‘866 patent also discloses purification of Rifaximin by performing crystallization of crude Rifaximin from a 7:3 mixture of ethyl alcohol/water followed by drying both under atmospheric pressure and under vacuum. The crystalline form which is obtained has not been characterized.
U.S. Patent No. 7,045,620 describes three polymorphic forms α, β and γ of Rifaximin. Form a and β show pure crystalline characteristics while the γ form is poorly crystalline. These polymorphic forms are differentiated on the basis of water content and PXRD. This patent also discloses processes for preparation of these polymorphs which involve use of specific reaction conditions during crystallization like dissolving Rifaximin in ethyl alcohol at 45-65°C, precipitation by adding water to form a suspension, filtering suspension and washing the resulted solid with demineralized water, followed by drying at room temperature under vacuum for a period of time between 2 and 72 hours. Crystalline forms a and β are obtained by immediate filtration of suspension when temperature of reaction mixture is brought to 0°C and poorly crystalline form γ is obtained when the reaction mixture is stirred for 5-6 hours at 0°C and then filtered the suspension. In addition to above these forms are also characterized by specific water content. For a form water content should be lower than 4.5%, for β form it should be higher than 4.5% and to obtain γ form, water content should be below 2%.
U.S. Patent No. 7,709,634 describes an amorphous form of Rifaximin which is prepared by dissolving Rifaximin in solvents such as alkyl esters, alkanols and ketones and precipitating by addition of anti-solvents selected from hydrocarbons, ethers or mixtures thereof.
U.S. Patent No. 8,193,196 describes two polymorphic forms of Rifaximin, designated δ and ε respectively. Form δ has water content within the range from 2.5 to 6% by weight (preferably from 3 to 4.5%).
U.S. Patent No 8,067,429 describes a-dry, β-1, β-2, ε-dry and amorphous forms of Rifaximin.
U.S. Patent No. 8,227,482 describes polymorphs Form μ, Form π, Form Omicron, Form Zeta, Form Eta, Form Iota and Form Xi of Rifaximin.
International application publications WO 2008/035109, WO 2008/155728, WO 2012/035544, WO 2012/060675, and WO 2012/156533 describes various amorphous or poorly crystalline forms of Rifaximin.
These polymorphic forms are obtained under different experimental conditions and are characterized by XRPD pattern.
The polymorphic forms of Rifaximin obtained from the prior art methods have specific water content. Transition between different polymorphic forms of Rifaximin occurs by drying or wetting of the synthesized Rifaximin. Hence, it is evident from above that Rifaximin can exist in number of polymorphic forms, formation of these polymorphic forms depends upon specific reaction conditions applied during crystallization and drying.
Rifaximin is a semi-synthetic, rifamycin-based non-systematic antibiotic. It is chemically termed as (2S,16Z,18E,20S,21S,22R,23R,24R,25S,26 S,27S, 28E)-5,6,21,23,255-pentahydroxy-27-methoxy-2,4,11,16,20,22,24,26-octamethyl-2,7-(epoxypentadeca-[1,11,13]trienimino)benzofuro[4,5-e]pyrido[1,2-a]-benzimida-zole-1,15(2H)-dione,25-acetate (I).
Rifaximin is used for treatment of travelers’ diarrhea caused by noninvasive strains of Escherichia coli.
Rifaximin was first disclosed in US4341785 which also discloses a process for its preparation and a method for crystallization of rifaximin using suitable solvents or mixture of solvents. However, this patent does not mention the polymorphism of rifaximin.
Canadian patent CA1215976 discloses a process for the synthesis of imidazo rifamycins which comprises reacting rifamycin S with 2-amino-4-methyl pyridine.
US4557866 discloses a process for preparation of rifaximin, but does not mention the polymorphs of rifaximin.
US7045620 discloses crystalline polymorphic forms of rifaximin which are termed as rifaximin α, rifaximin β and rifaximin γ. These polymorphic forms are characterized using X-ray powder diffraction. Further this patent mentions that γ form is poorly crystalline with a high content of amorphous component. This patent also discloses processes for preparation of these polymorphs which involve use of processes of crystallization and drying as disclosed in US4557866along with control of temperature at which the product is crystallized, drying process, water content thereof. Further, according to this patent, crystal formation depends upon the presence of water within the crystallization solvent.
The above patent discloses rifaximin α which is characterized by water content lower than 4.5% & powder X-ray diffractogram having significant peaks are at values of diffraction angles 2θ of 6.6°; 7.4°; 7.9°, 8.8°, 10.5°, 11.1 °, 11.8°, 12.9°, 17.6°, 18.5°, 19.7°, 21.0°, 21.4°, 22.1°; rifaximin β which is characterized by water content higher than 4.5% & powder X-ray diffractogram having significant peaks are at values of diffraction angles 2θ of 5.4°; 6.4°; 7.0°, 7.8°, 9.0°, 10.4°, 13.1°, 14.4°, 17.1°, 17.9°, 18.3°, 20.9° and rifaximin γ which is characterized by poorer powder X-ray diffractogram because of poor crystallinity. The significant peaks are at values of diffraction angles 2θ of 5.0°; 7.1°; 8.4°.
US2005/0272754 also discloses polymorphs of rifaximin namely rifaximin α form, rifaximin β form & rifaximin γ form characterized by powder X-ray diffractogram, intrinsic dissolution rates and processes of preparation of polymorphic forms of rifaximin. However, none of the above patents disclose a wholly amorphous form of rifaximin.
It is a well known fact that different polymorphic forms of the same drug may have substantial differences in certain pharmaceutically important properties. The amorphous form of a drug may exhibit different dissolution characteristics and in some case different bioavailability patterns compared to crystalline forms.
Further, amorphous and crystalline forms of a drug may have different handling properties, dissolution rates, solubility, and stability.
Furthermore, different physical forms may have different particle size, hardness and glass transition temperatures. Amorphous materials do not exhibit the three-dimensional long-range orders found in crystalline materials, but are structurally more similar to liquids where the arrangement of molecules is random.
Amorphous solids do not give a definitive x-ray diffraction pattern (XRD). In addition, amorphous solids do not give rise to a specific melting point and tend to liquefy at some point beyond the glass transition temperature. Because amorphous solids do not have lattice energy, they usually dissolve in a solvent more rapidly and consequently may provide enhanced bioavailability characteristics such as a higher rate and extent of absorption of the compound from the gastrointestinal tract. Also, amorphous forms of a drug may offer significant advantages over crystalline forms of the same drug in the manufacturing process of solid dosage form such as compressibility.
PATENT
https://www.google.com/patents/EP2069363B1?cl=e
The schematic representation for preparation of amorphous rifaximin is as follows :
Amorphous rifaximin according to the present invention can be characterized by various parameters like solubility, intrinsic dissolution, bulk density, tapped density.
Rifaximin is known to exist in 3 polymorphic Forms namely α Form, β Form & γ Form of which the α Form is thermodynamically the most stable. Hence, the amorphous form of rifaximin was studied in comparison with α Form.
Further, when intrinsic dissolution of amorphous rifaximin is carried out against the α Form, it is observed that the amorphous rifaximin has better dissolution profile than α Form which is shown in table below (this data is also shown graphically in Figure 3):
Dissolution medium : 1000 ml of 0.1M Sodium dihydrogen phosphate monohydrate + 4.5g of sodium lauryl sulphate
Temperature : 37±0.5°C
Rotation speed : 100 rpm
Particle size : Amorphous rifaximin – 11 microns
α Form of rifaximin – 13 microns
| Time in minutes | % Release of Amorphous Rifaximin | % Release of α Form of Rifaximin |
| 15 | 1.1 | 0.8 |
| 30 | 1.9 | 1.8 |
| 45 | 2.9 | 3.0 |
| 60 | 3.7 | 4.4 |
| 120 | 8.1 | 11.0 |
| 180 | 12.6 | 18.0 |
| 240 | 16.6 | 24.6 |
| 360 | 24.7 | 38.7 |
| 480 | 32.0 | 47.5 |
| 600 | 39.5 | 52.7 |
| 720 | 46.4 | 56.4 |
| 960 | 60.4 | 62.9 |
| 1200 | 72.9 | 67.8 |
| 1400 | 83.0 | 72.7 |
CLIP
Rifaximin (CAS NO.: 80621-81-4), with other name of 4-Deoxy-4-methylpyrido[1,2-1,2]imidazo[5,4-c]rifamycin SV, could be produced through many synthetic methods.
Following is one of the reaction routes:

The reaction of rifamycin S (I) with pyridine perbromide (II) in 2-propanol/chloroform (70/30) mixture at 0 C gives 3-bromorifamicin S (III), which is then condensed with 2-amino-4-methyl-pyridine (IV) at 10 C. The o-quinoniminic compound (V) is then obtained. This compound is finally reduced with ascorbic acid.
POLYMORPHISM
Rifaximin (INN; see The Merck Index, XIII Ed., 8304) is an antibiotic belonging to the rifamycin class, exactly it is a pyrido-imidazo rifamycin described and claimed in Italian Patent IT 1154655, while European Patent EP 0161534 describes and claims a process for its production starting from rifamycin O (The Merck Index, XIII Ed., 8301).
Both these patents describe the purification of rifaximin in a generic way stating that crystallization can be carried out in suitable solvents or solvent systems and summarily showing in some examples that the reaction product can be crystallized from the 7:3 mixture of ethyl alcohol/water and can be dried both under atmospheric pressure and under vacuum without specifying in any way either the experimental conditions of crystallization and drying, or any distinctive crystallographic characteristic of the obtained product.
The presence of different polymorphs had just not been noticed and therefore the experimental conditions described in both patents had been developed with the goal to get a homogeneous product having a suitable purity from the chemical point of view, independent from the crystallographic aspects of the product itself.
It has now been found, unexpectedly, that there are several polymorphous forms whose formation, besides the solvent, depends on time and temperature conditions under which both crystallization and drying are carried out.
In the present application, these orderly polymorphous forms will be, later on, conventionally identified as rifaximin α (FIG. 1) and rifaximin β (FIG. 2) on the basis of their respective specific diffractograms, while the poorly crystalline form with a high content of amorphous component will be identified as rifaximin γ (FIG. 3).
Rifaximin polymorphous forms have been characterized through the technique of the powder X-ray diffraction.
The identification and characterization of these polymorphous forms and, simultaneously, the definition of the experimental conditions for obtaining them is very important for a compound endowed with pharmacological activity which, like rifaximin, is marketed as medicinal preparation, both for human and veterinary use. In fact it is known that the polymorphism of a compound that can be used as active ingredient contained in a medicinal preparation can influence the pharmaco-toxicologic properties of the drug. Different polymorphous forms of an active ingredient administered as drug under oral or topical form can modify many properties thereof like bioavailability, solubility, stability, colour, compressibility, flowability and workability with consequent modification of the profiles of toxicological safety, clinical effectiveness and productive efficiency.
What mentioned above is confirmed by the fact that the authorities that regulate the grant of marketing authorization of the drugs market require that the manufacturing methods of the active ingredients are standardized and controlled in such a way that they give homogeneous and sound results in terms of polymorphism of production batches (CPMP/QWP/96, 2003—Note for Guidance on Chemistry of new Active Substance; CPMP/ICH/367/96—Note for guidance specifications: test procedures and acceptance criteria for new drug substances and new drug products: chemical substances; Date for coming into operation: May 2000).
The need for the above-mentioned standardization has further been strengthened in the field of the rifamycin antibiotics by Henwood S. Q., de Villiers M. M., Liebenberg W. and Lotter A. P., Drug Development and Industrial Pharmacy, 26 (4), 403-408, (2000), who have ascertained that different production batches of the rifampicin (INN) made from different manufacturers differ from each other in that they show different polymorphous characteristics, and as a consequence they show different dissolution profiles, along with a consequent alteration of the respective pharmacological properties.
By applying the crystallization and drying processes generically disclosed in the previous patents IT 1154655 and EP 0161534 it has been found that under some experimental conditions a poorly crystalline form of rifaximin is obtained, while under other experimental conditions other polymorphic crystalline forms of Rifaximin are obtained. Moreover it has been found that some parameters, absolutely not disclosed in the above-mentioned patents, like for instance preservation conditions and the relative ambient humidity, have the surprising effect to determine the polymorph form.
The polymorphous forms of rifaximin object of the present patent application were never seen or hypothesized, while thinking that, whichever method was used within the range of the described condition, a sole homogeneous product would always have been obtained, irrespective of crystallizing, drying and preserving conditions. It has now been found that the formation of α, β and γ forms depends both on the presence of water within the crystallization solvent, on the temperature at which the product is crystallized and on the amount of water present in the product at the end of the drying phase. Form α, form β and form γ of rifaximin have then been synthesized and they are the object of the invention.
Moreover it has been found that the presence of water in rifaximin in the solid state is reversible, so that water absorption and/or release can take place in time in presence of suitable ambient conditions; consequently rifaximin is susceptible of transition from one form to another, also remaining in the solid state, without need to be again dissolved and crystallized. For instance polymorph α, getting water by hydration up to a content higher than 4.5%, turns into polymorph β, which in its turn, losing water by drying up to a content lower than 4.5%, turns into polymorph α.
These results have a remarkable importance as they determine the conditions of industrial manufacturing of some steps of working which could not be considered critical for the determination of the polymorphism of a product, like for instance the washing of a crystallized product, or the preservation conditions of the end product, or the characteristics of the container in which the product is preserved.
The above-mentioned α, β and γ forms can be advantageously used as pure and homogeneous products in the manufacture of medicinal preparations containing rifaximin.
As already said, the process for manufacturing rifaximin from rifamycin O disclosed and claimed in EP 0161534 is deficient from the point of view of the purification and identification of the product obtained; it shows some limits also from the synthetic point of view as regards, for instance, the very long reaction times, from 16 to 72 hours, not very suitable to an industrial use and moreover because it does not provide for the in situ reduction of rifaximin oxidized that may be formed within the reaction mixture.
Therefore, a further object of the present invention is an improved process for the industrial manufacturing of the α, β and γ forms of rifaximin, herein claimed as products and usable as defined and homogeneous active ingredients in the manufacture of the medicinal preparations containing such active ingredient.
PATENT
https://www.google.com/patents/US20090234114
FIG. 1 is a powder X-ray diffractogram of rifaximin polymorphic form α.
FIG. 2 is a powder X-ray diffractogram of rifaximin polymorphic form β.
FIG. 3 is a powder X-ray diffractogram of rifaximin polymorphic form γ.

Rifaximin (INN; see The Merck Index, XIII Ed., 8304, CAS no. 80621-81-4), IUPAC nomenclature (2S,16Z,18E,20S,21S,22R,23R,24R,25S,26S,27S,28E)-5,6,21,23,25 pentahydroxy-27-methoxy-2,4,11,16,20,22,24,26-octamethyl-2,7-(epoxypentadeca-(1,11,13)trienimino)benzofuro(4,5-e)pyrido(1,2,-a)benzimidazole-1,15(2H)-dione,25-acetate) is a semi-synthetic antibiotic belonging to the rifamycin class of antibiotics. More precisely rifaximin is a pyrido-imidazo rifamycin described in the Italian patent IT 1154655, whereas the European patent EP 0161534 discloses a process for rifaximin production using rifamycin O as starting material (The Merck Index, XIII Ed., 8301).
U.S. Pat. No. 7,045,620, US 2008/0262220, US 7,612,199, US 2009/0130201 and Cryst. Eng. Comm., 2008, 10 1074-1081 (2008) disclose new forms of rifaximin.
WO 2008/035109 A1 discloses a process to prepare amorphous rifaximin, which comprises reaction of rifamycin S with 2-amino-4 picoline in presence of organic solvent like dichloromethane, ethylacetate, dichloroethylene, chloroform, in an inert atmosphere. When water is added to the reaction mixture, a solid precipitate corresponding to amorphous rifaximin is obtained.
The process described in this document can be assimilated to a crash precipitation, wherein the use of an anti-solvent causes the precipitation of rifaximin without giving any information about the chemical physical and biological characteristics of the rifaximin obtained.
WO 2009/108730 A2 describes different polymorphous forms of rifaximin and also amorphous forms of rifaximin. Amorphous forms are prepared by milling and crash precipitation and with these two different methods the amorphous rifaximin obtained from these two different processes has the same properties.

FIG. 5: FT-IR spectrum of rifaximin obtained by spray drying process.

Patent
Rifaximin, lUPAC name:
(2S,16Z,18E,20S,21 S,22H,23H,24H,25S,26S,27S,28£)-5,6,21 ,23,25-pentahydroxy- 27-methoxy-2,4,1 1 ,16,20,22,24,26-octamethyl-2,7-(epoxypentadeca-[1 ,1 1 ,13]-trienimmino)-benzofuro-[4,5-e]-pirido-[1 ,2-oc]-benzimidazol-1 , 15(2 -/)-dione,25-acetate, is the compound of formula (I):

Rifaximin is a broad-spectrum antibiotic belonging to the family of rifamycins, devoid of systemic activity. In view of its physicochemical properties, it is not adsorbed in the gastrointestinal tract and therefore exerts its antimicrobial action inside the gastrointestinal tract. Rifaximin therefore has applications in the treatment of diarrhoea and of microbial infections of the gastrointestinal tract typically caused by E. coli, a microorganism which, being incapable of passing through the mucosa of the gastrointestinal tract, remains in contact with the gastrointestinal fluids. Rifaximin also has applications for the treatment of irritable bowel syndrome, Crohn’s disease, diverticulitis and for antibiotic prophylaxis preceding surgical operations on the intestines.
Rifaximin was obtained and described for the first time in the EP161534 starting from rifamycin O and 2-amino-4-picoline in the presence of ethanol/water and
ascorbic acid/HCI to obtain raw rifaximin which is then treated with Ethanol/water to obtain crystallized rifaximin.
Polymorphic forms of rifaximin, and processes for their synthesis and purification, are described in various documents of the known art.
Rifaximin K was firstly described in WO2012/156951 . Such a crystalline form resulted to be more stable in the presence of humidity than the other known crystalline forms of rifaximin, thus enabling the storage, even for prolonged periods. Such a polymorph was obtained by a process starting from rifaximin comprising the following steps: -suspending or dissolving rifaximin in a 1 ,2-dimethoxyethane based solvent, recovering the product and drying to remove said 1 ,2-dimethoxyethane based solvent. In one of the embodiments of the invention 1 ,2-dimethoxyethane is used as the unique solvent of rifaximin, in other 1 ,2-dimethoxyethane is described as used in combination of n-heptane, methanol, acetonitrile, R-COO-R1 esters wherein R and R1 are independently C3-C6 alkyl radicals, and C3-C7 alkyl ketones, ethanol, isopropanol and water.
The synthesis of 4-deoxypyrido(1′,2′-1,2)imidazo(5,4-c)rifamycin SV derivatives
J Antibiot 1984, 37(12): 1611
LAST STEP DEPICTED AGAIN
Treatment of rifamycin S (I) with Pyr·Br2 in 2-PrOH/CHCl3 gives 3-bromorifamycin S (II) (1), which upon cyclocondensation with 2-amino-4-methyl-pyridine (III) (1,2,3) in CHCl3 (2) or EtOH (3) yields imine derivative (IV). Finally, reduction of (IV) with L-(+)- ascorbic acid (1,2,3) in MeOH (2) or EtOH (3) provides the target rifaximin (1,2,3).
PATENT
WO 2005044823, WO 2012035544, WO 2015014984
Rifaximin is prepared by the cyclocondensation of rifamycin-O with 2-amino-4-picoline in a solvent mixture such as acetone, acetonitrile, EtOH, MIBK, propylene glycol, i-PrOH or t-BuOH and H2O at 50 °C or EtOH/aceone/H2O or optionally in the presence of I2 in CH2Cl2
PATENT
The process is shown in the scheme given below:

Rifamycin-S
3-halo-Rifamycin-S

Examples
Example 1;
5g of Rifamycin S, 3.1 gms of 2-amino-4-methyl pyridine, 0.45 g of iodine, 1.65 ml of acetic acid and 20ml of acetonitrile were charged in a clean and dry round bottom flask followed by stirring the resultant reaction mixture at about 30°C for about 30 hours. The reaction progress was monitored by TLC, after completion of reaction, the reaction mass was quenched by adding a mixture of 4.0g of ascorbic acid dissolved in 20 ml of water. The resultant reaction suspension was stirred at about 25°C for about 15mins. 25 ml of dichloromethane was charged and stirred for about 15mins. followed by separation of organic and aqueous phases. The aqueous phase was extracted with 25 ml of dichloromethane followed by separation of organic and aqueous phases. The organic phases were combined and distilled at below about 50°C to yield Rifaximin as residue. 11.25ml of purified water and 11.25ml of ethanol were charged to the residue and stirred at about 30°C for about 15 mins. The resultant reaction
suspension was heated to about 75°C and stirred for about 30mins. The resultant reaction solution further cooled to about 25 °C and stirred for about 2 hours followed by further cooling to about 5°C for about 3 hours. The solid precipitated was filtered and the solid was washed with a mixture of 2.5ml of ethanol and 2.5 ml of purified water. The solid obtained was dried at about 50°C for about 10 hours to afford 3 g. of Rifaximin as crystalline form. Purity by HPLC: 99.85 area %.
PAPER
European journal of medicinal chemistry (2015), 103, 551-62
Patent
https://www.google.com/patents/WO2013027227A1?cl=en
Examples
Example 1 : Purification of Rifamycin S
Rifamycin S (500g) and Ethanol (1.5L) were stirred and refluxed for 1 hour. The reaction mixture was then cooled slowly to ambience, stirred at this temperature for 2 hour and filtered. The product dried in vacuum oven at 40 °C to obtain 475g of pure Rifamycin S showing the des acetyl impurity below to 0.6%.
Example 2: Preparation of rifaximin
Rifamycin S (300 g) was stirred in dichloromethane (900 ml) at room temperature for 15 minutes to get a clear solution and then 2-Amino-4-methyl pyridine (139.2g) was added at room temperature under nitrogen atmosphere. Iodine (57. Og) dissolved in dichloromethane (2100ml), was added drop wise in 30-45 minutes at room temperature. The reaction mass was stirred for 22-24 hours at 25-30 °C. After completion of the reaction, a 20% solution of L(-) ascorbic acid in water (300 ml) was added. The reaction mixture was stirred for 45-60 minutes at room temperature and then cooled to 10-15 °C. The pH of the resulting solution was adjusted to 1.5-2.0 with slow addition of dilute hydrochloric acid under stirring. The reaction mass was stirred for 15-20 minutes and layers were separated. The organic layer was washed with demineralized water (1500 ml), 10% sodium thiosulfate solution (1500 ml) and with demineralized water till pH was neutral. The solvent was distilled off under vacuum at 40-45 °C to get a residue which was taken in cyclohexane (1500 ml) and stirred for 1 hour. The resulting solid was filtered, washed with cyclohexane (300 ml) crystallized from a mixture of ethyl alcohol and water (600ml; 420ml ethyl alcohol and 180 ml water) to get 240g of crude rifaximin having purity 99.3% by HPLC.
Example 3: Preparation of rifaximin
Step-1: Preparation of crude rifaximin
Rifamycin S (300 g) was stirred in dichloromethane (900 ml) at room temperature for 15 minutes to get a clear solution and then 2-amino-4-methyl pyridine (139.2g) was added at room temperature under nitrogen atmosphere. Iodine (57. Og) dissolved in dichloromethane (2100ml), was added drop wise in 30-45 minutes at room temperature and was stirred for 22-24 hours. After completion of the reaction, a 20% solution of L (-) ascorbic acid in water (300 ml) was added and stirred for 45-60 minutes. The reaction mass was cooled to 10-15 °C and pH of the resulting solution was adjusted to 1.5-2.0 with slow addition of dilute hydrochloric acid under stirring. The reaction mass was stirred for 15-20 minutes and layers were separated and the organic layer was washed with demineralized water (1500 ml), with 10% sodium thiosulfate solution (1500 ml) and demineralized water till pH was neutral. The solvent was distilled off under vacuum at 40-45 °C to obtain a residue which was crystallized from a mixture of ethyl alcohol and water (378ml ethyl alcohol and 162 ml water) and dried at 35-40 °C to obtain 240g crude rifaximin having purity 98.8% by HPLC. Step-2: Purification of crude rifaximin
Crude rifaximin (240g) was stirred in dichloromethane (2400ml) at room temperature, a neutral alumina (240g) was added, stirred for 1 hour and filtered. The solvent was then distilled off and residue was treated with ethyl acetate (2400ml) and stirred to dissolution. The resulting residue was crystallized from a mixture of ethyl alcohol and water (302ml ethyl alcohol and 130ml water) and dried at 35-40 “C to obtain 192g of rifaximin having purity 99.8% by HPLC.
PATENT
https://www.google.com/patents/US9018225
PAPER
PATENTS
| US4341785 | May 11, 1981 | Jul 27, 1982 | Alfa Farmaceutici S.P.A. | Imidazo-rifamycin derivatives with antibacterial utility |
| US4557866 | Apr 26, 1985 | Dec 10, 1985 | Alfa Farmaceutici S.P.A. | Process for the synthesis of pyrido-imidazo rifamycins |
| US7045620 | Dec 5, 2003 | May 16, 2006 | Alfa Wassermann, S.P.A. | Polymorphous forms of rifaximin, processes for their production and use thereof in medicinal preparations |
| US7612199 | Jun 4, 2009 | Nov 3, 2009 | Alfa Wassermann, S.P.A. | Polymorphic forms α, β, and γ of rifaximin |
| US7902206 | Mar 8, 2011 | Alfa Wassermann, S.P.A. | Polymorphic forms α, β and γ of rifaximin | |
| US7906542 | May 13, 2008 | Mar 15, 2011 | Alfa Wassermann, S.P.A. | Pharmaceutical compositions comprising polymorphic forms α, β, and γ of rifaximin |
| US7915275 | Mar 29, 2011 | Alfa Wassermann, S.P.A. | Use of polymorphic forms of rifaximin for medical preparations | |
| US7923553 | Apr 12, 2011 | Alfa Wassermann, S.P.A. | Processes for the production of polymorphic forms of rifaximin | |
| US7928115 | Apr 19, 2011 | Salix Pharmaceuticals, Ltd. | Methods of treating travelers diarrhea and hepatic encephalopathy | |
| US8158644 | Apr 17, 2012 | Alfa Wassermann, S.P.A. | Pharmaceutical compositions comprising polymorphic forms α, β, and γ of rifaximin | |
| US8158781 | Mar 4, 2011 | Apr 17, 2012 | Alfa Wassermann, S.P.A. | Polymorphic forms α, β and γ of rifaximin |
| US8193196 | Feb 27, 2006 | Jun 5, 2012 | Alfa Wassermann, S.P.A. | Polymorphous forms of rifaximin, processes for their production and use thereof in the medicinal preparations |
| US20050272754 * | May 24, 2005 | Dec 8, 2005 | Alfa Wassermann S.P.A. | Polymorphic forms of rifaximin, processes for their production and uses thereof |
| Reference | ||
|---|---|---|
| 1 | Viscomi, G. C., et al., “Crystal forms of rifaximin and their effect on pharmaceutical properties“, Cryst Eng Comm, 2008, 10, 1074-1081, (May 28, 2008), 1074-1081. | |
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| US9186355 | Mar 30, 2015 | Nov 17, 2015 | Novel Laboratories | Rifaximin crystalline forms and methods of preparation thereof |
| WO2008035109A1 * | Sep 24, 2007 | Mar 27, 2008 | Cipla Limited | Rifaximin |
| WO2009108730A2 * | Feb 25, 2009 | Sep 3, 2009 | Salix Pharmaceuticals, Ltd. | Forms of rifaximin and uses thereof |
| WO2011080691A1 * | Dec 27, 2010 | Jul 7, 2011 | Silvio Massimo Lavagna | Method for the production of amorphous rifaximin |
| EP1698630A1 * | Mar 3, 2005 | Sep 6, 2006 | ALFA WASSERMANN S.p.A. | New polymorphous forms of rifaximin, processes for their production and use thereof in the medicinal preparations |
| US20080262220 * | May 13, 2008 | Oct 23, 2008 | Giuseppe Claudio Viscomi | Polymorphic forms alpha, beta and gamma of rifaximin |
| US20090082558 * | Sep 20, 2007 | Mar 26, 2009 | Apotex Pharmachem Inc. | Amorphous form of rifaximin and processes for its preparation |
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| WO2015014984A1 * | Aug 1, 2014 | Feb 5, 2015 | Clarochem Ireland Ltd. | A process for preparing rifaximin k |
| CN103360357A * | Aug 7, 2013 | Oct 23, 2013 | 中国药科大学 | A simvastatin-gliclazide co-amorphous compound |
| US9359374 | Jun 13, 2013 | Jun 7, 2016 | Apotex Pharmachem Inc. | Polymorphic forms of rifaximin |
| US4341785 * | May 11, 1981 | Jul 27, 1982 | Alfa Farmaceutici S.P.A. | Imidazo-rifamycin derivatives with antibacterial utility |
| US4557866 * | Apr 26, 1985 | Dec 10, 1985 | Alfa Farmaceutici S.P.A. | Process for the synthesis of pyrido-imidazo rifamycins |
| US7045620 * | Dec 5, 2003 | May 16, 2006 | Alfa Wassermann, S.P.A. | Polymorphous forms of rifaximin, processes for their production and use thereof in medicinal preparations |
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| US8518949 | Jun 4, 2012 | Aug 27, 2013 | Alfa Wassermann S.P.A. | Polymorphous forms of rifaximin, processes for their production and use thereof in the medicinal preparations |
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| Patents |
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| Systematic (IUPAC) name | |
|---|---|
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(2S,16Z,18E,20S,21S,22R,23R,24R,25S,26S,27S,28E)-5,6,21,23,25-pentahydroxy-27-methoxy-2,4,11,16,20,22,24,26-octamethyl-2,7-(epoxypentadeca-[1,11,13]trienimino)benzofuro
[4,5-e]pyrido[1,2-a]-benzimida-zole-1,15(2H)-dione,25-acetate |
|
| Clinical data | |
| Trade names | Xifaxan, Xifaxanta, Normix, Rifagut |
| AHFS/Drugs.com | Monograph |
| MedlinePlus | a604027 |
| Pregnancy category |
|
| Routes of administration |
Oral |
| Legal status | |
| Legal status |
|
| Pharmacokinetic data | |
| Bioavailability | < 0.4% |
| Metabolism | Hepatic |
| Biological half-life | 6 hours |
| Excretion | Fecal (97%) |
| Identifiers | |
| CAS Number | 80621-81-4 |
| ATC code | A07AA11 (WHO) D06AX11(WHO) QG51AA06 (WHO)QJ51XX01 (WHO) |
| PubChem | CID 6436173 |
| DrugBank | DB01220 |
| ChemSpider | 10482302 |
| UNII | L36O5T016N |
| KEGG | D02554 |
| ChEBI | CHEBI:75246 |
| ChEMBL | CHEMBL1617 |
| Chemical data | |
| Formula | C43H51N3O11 |
| Molar mass | 785.879 g/mol |
Giuseppe Viscomi, Manuela Campana, Dario Braga, Donatella Confortini, Vincenzo Cannata, Paolo Righi, Goffredo Rosini, “Polymorphic forms of rifaximin, processes for their production and uses thereof.” U.S. Patent US20050272754, issued December 08, 2005.
///////Rifaximin, Rifaxidin, Rifacol, Xifaxan, Normix, Rifamycin L 105, 80621-81-4
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