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ORGANIC SPECTROSCOPY

Read all about Organic Spectroscopy on ORGANIC SPECTROSCOPY INTERNATIONAL 

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DR ANTHONY MELVIN CRASTO Ph.D

DR ANTHONY MELVIN CRASTO Ph.D

DR ANTHONY MELVIN CRASTO, Born in Mumbai in 1964 and graduated from Mumbai University, Completed his Ph.D from ICT, 1991,Matunga, Mumbai, India, in Organic Chemistry, The thesis topic was Synthesis of Novel Pyrethroid Analogues, Currently he is working with AFRICURE PHARMA, ROW2TECH, NIPER-G, Department of Pharmaceuticals, Ministry of Chemicals and Fertilizers, Govt. of India as ADVISOR, earlier assignment was with GLENMARK LIFE SCIENCES LTD, as CONSUlTANT, Retired from GLENMARK in Jan2022 Research Centre as Principal Scientist, Process Research (bulk actives) at Mahape, Navi Mumbai, India. Total Industry exp 32 plus yrs, Prior to joining Glenmark, he has worked with major multinationals like Hoechst Marion Roussel, now Sanofi, Searle India Ltd, now RPG lifesciences, etc. He has worked with notable scientists like Dr K Nagarajan, Dr Ralph Stapel, Prof S Seshadri, etc, He did custom synthesis for major multinationals in his career like BASF, Novartis, Sanofi, etc., He has worked in Discovery, Natural products, Bulk drugs, Generics, Intermediates, Fine chemicals, Neutraceuticals, GMP, Scaleups, etc, he is now helping millions, has 9 million plus hits on Google on all Organic chemistry websites. His friends call him Open superstar worlddrugtracker. His New Drug Approvals, Green Chemistry International, All about drugs, Eurekamoments, Organic spectroscopy international, etc in organic chemistry are some most read blogs He has hands on experience in initiation and developing novel routes for drug molecules and implementation them on commercial scale over a 32 PLUS year tenure till date Feb 2023, Around 35 plus products in his career. He has good knowledge of IPM, GMP, Regulatory aspects, he has several International patents published worldwide . He has good proficiency in Technology transfer, Spectroscopy, Stereochemistry, Synthesis, Polymorphism etc., He suffered a paralytic stroke/ Acute Transverse mylitis in Dec 2007 and is 90 %Paralysed, He is bound to a wheelchair, this seems to have injected feul in him to help chemists all around the world, he is more active than before and is pushing boundaries, He has 100 million plus hits on Google, 2.5 lakh plus connections on all networking sites, 100 Lakh plus views on dozen plus blogs, 227 countries, 7 continents, He makes himself available to all, contact him on +91 9323115463, email amcrasto@gmail.com, Twitter, @amcrasto , He lives and will die for his family, 90% paralysis cannot kill his soul., Notably he has 38 lakh plus views on New Drug Approvals Blog in 227 countries......https://newdrugapprovals.wordpress.com/ , He appreciates the help he gets from one and all, Friends, Family, Glenmark, Readers, Wellwishers, Doctors, Drug authorities, His Contacts, Physiotherapist, etc He has total of 32 International and Indian awards

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New information about CEPs and inspections published by EDQM….see about Telangana, India


DR ANTHONY MELVIN CRASTO Ph.D's avatarDRUG REGULATORY AFFAIRS INTERNATIONAL

The European Directorate for the Quality of Medicines & Healthcare (EDQM) has published new information about the CEP procedure and its related inspections. Please read more about he latest updates from EDQM.

http://www.gmp-compliance.org/enews_4746_New-information-about-CEPs-and-inspections-published-by-EDQM_9196,S-WKS_n.html

The European Directorate for the Quality of Medicines & Healthcare (EDQM) has published new information about the CEP procedure and its related inspections.

1) Costs of inspections

The EDQM has published a new document which describes the inspection costs. The EDQM document PA/PH/CEP (12) 28 1R refers to a table of fees and inspection costs. The costs for the inspection as well as for the travel will be invoiced prior to the inspection. For a three day inspection, for example, the fee is 5000,- Euro. If the facility is located in Asia a flat rate of 6000,- Euro will be charged to cover the travel costs, food and accommodation for the inspector. The travel costs are less…

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CILNIDIPINE 西尼地平


 

 

Cilnidipine

西尼地平

CAS 132203-70-4

  • (E) – (±) 1 ,4 a dihydro-2 ,6 – dimethyl-4 – (3 – nitrophenyl) -3,5 – pyridinedicarboxylic acid, 2 – methoxy- ethyl butylester 3 – phenyl – 2 – propenyl ester FRC-8653 Cinalong
  • More FRC 8653 1,4-Dihydro-2 ,6-dimethyl-4-(3-nitrophenyl) 3 ,5-pyridinedicarboxylic acid 2-methoxyethyl (2E)-3-phenyl-2-propenyl ester
  • Molecular formula:27 H 28 N 2 O 7
  • Molecular Weight:492.52
CAS Name: 1,4-Dihydro-2,6-dimethyl-4-(3-nitrophenyl)-3,5-pyridinedicarboxylic acid 2-methoxyethyl (2E)-3-phenyl-2-propenyl ester
Additional Names: (±)-(E)-cinnamyl 2-methoxyethyl 1,4-dihydro-2,6-dimethyl-4-(m-nitrophenyl)-3,5-pyridinedicarboxylate
Cinnamyl 2-methoxyethyl 4-(3-nitrophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate
Manufacturers’ Codes: FRC-8653
Trademarks: Atelec (Morishita); Cinalong (Fujirebio); Siscard (Boehringer, Ing.)
Percent Composition: C 65.84%, H 5.73%, N 5.69%, O 22.74%
Properties: Crystals from methanol, mp 115.5-116.6°. LD50 in male, female mice, rats (mg/kg): ³5000, ³5000, ³5000, 4412 orally;³5000 all species s.c.; 1845, 2353, 441, 426 i.p. (Wada).
Melting point: mp 115.5-116.6°
Toxicity data: LD50 in male, female mice, rats (mg/kg): ³5000, ³5000, ³5000, 4412 orally; ³5000 all species s.c.; 1845, 2353, 441, 426 i.p. (Wada)
Ajinomoto (INNOVATOR)
 Antihypertensive; Dihydropyridine Derivatives; Calcium Channel Blocker; Dihydropyridine Derivatives.

 

Cilnidipine (INN) is a calcium channel blocker. It is sold as Atelec in Japan, asCilaheart, Cilacar in India, and under various other trade names in East Asian countries.

Cilnidipine is a dual blocker of L-type voltage-gated calcium channels in vascular smooth muscle and N-type calcium channels in sympathetic nerve terminals that supply blood vessels. However, the clinical benefits of cilnidipine and underlying mechanisms are incompletely understood.

Clinidipine is the novel calcium antagonist accompanied with L-type and N-type calcium channel blocking function. It was jointly developed by Fuji Viscera Pharmaceutical Company, Japan and Ajinomoto, Japan and approved to come into market for the first time and used for high blood pressure treatment in 1995. in india j b chemicals & pharmaceuticals ltd and ncube pharmaceutical develope a market of cilnidipine.

Hypertension is one of the most common cardiovascular disease states, which is defined as a blood pressure greater than or equal to 140/90 mm Hg. Recently, patients with adult disease such as hypertension have rapidly increased. Particularly, since damages due to hypertension may cause acute heart disease or myocardial infarction, etc., there is continued demand for the development of more effective antihypertensive agent.

Meanwhile, antihypertensive agents developed so far can be classified into Angiotensin II Receptor Blocker (ARB), Angiotensin-Converting Enzyme Inhibitor (ACEI) or Calcium Chanel Blocker (CCB) according to the mechanism of actions. Particularly, ARB or CCB drugs manifest more excellent blood pressure lowering effect, and thus they are more frequently used.

However, these drugs have a limit in blood pressure lowering effects, and if each of these drugs is administered in an amount greater than or equal to a specific amount, various side-effects may be caused. Therefore, there have been many attempts in recent years to obtain more excellent blood pressure lowering effect by combination therapy or combined preparation which combines or mixes two or more drugs.

Particularly, since side-effect due to each drug is directly related to the amount or dose of a single drug, there have been active attempts to combine or mix two or more drugs thereby obtaining more excellent blood pressure lowering effect through synergism of the two or more drugs while reducing the amount or dose of each single drug.

For example, US 20040198789 discloses a pharmaceutical composition for lowering blood pressure combining lercanidipine, one of CCB, and valsartan, irbesartan or olmesartan, one of ARB, etc. In addition, a combined preparation composition which combines or mixes various blood pressure lowering drugs or combination therapy thereof has been disclosed.

cilnidipine Compared with other calcium antagonists, clinidipine can act on the N-type calcium-channel that existing sympathetic nerve end besides acting on L-type calcium-channel that similar to most of the calcium antagonists. Due to its N-type calcium-channel blocking properties, it has more advantages compared to conventional calcium-channel blockers. It has lower incidence of Pedal edema, one of the major adverse effects of other calcium channel blockers. Cilnidipine has similar blood pressure lowering efficacy as compared to amlodipine. One of the distinct property of cilnidipine from amlodipine is that it does not cause reflex tachycardia.

In recent years, cardiovascular disease has become common, the incidence increased year by year, about a patient of hypertension in China. 3-1. 500 million, complications caused by hypertension gradually increased, and more and more young patients with hypertension technology. In recent years, antihypertensive drugs also have great development, the main first-line diuretic drug decompression 3 – blockers, calcium channel blockers, angiotensin-converting enzyme inhibitors, ar blockers and vascular angiotensin II (Ang II) receptor antagonist.

In the anti-hypertensive drugs, calcium antagonists are following a – blockers after another rapidly developing cardiovascular drugs, has been widely used in clinical hypertension, angina and other diseases, in cardiovascular drugs in the world, ranked first.

Cilnidipine for the long duration of the calcium channel blockers, direct relaxation of vascular smooth muscle, dilation of peripheral arteries, the peripheral resistance decreased, with lower blood pressure, heart rate without causing a reflex effect.

Cilnidipine is a dihydropyridine CCB as well as an antihypertensive. Cilnidipinehas L- and N-calcium channel blocking actions. Though many of the dihydropyridine CCBs may cause an increase in heart rate while being effective for lowering blood pressure, it has been confirmed that cilnidipine does not increase the heart rate and has a stable hypotensive effect. (Takahiro Shiokoshi, “Medical Consultation & New Remedies” vol. 41, No. 6, p. 475-481)

  • http://www.mcyy.com.cn/e-product2.asp
  • Löhn M, Muzzulini U, Essin K, et al. (May 2002). “Cilnidipine is a novel slow-acting blocker of vascular L-type calcium channels that does not target protein kinase C”. J. Hypertens.20 (5): 885–93. PMID12011649.

read more on dipine series………http://organicsynthesisinternational.blogspot.in/p/dipine-series.html

Cilnidipine (CAS NO.: 132203-70-4), with its systematic name of (+-)-(E)-Cinnamyl 2-methoxyethyl 1,4-dihydro-2,6-dimethyl-4-(m-nitrophenyl)-3,5-pyridinedicarboxylate, could be produced through many synthetic methods.

Following is one of the synthesis routes: By cyclization of 2-(3-nitrobenzylidene)acetocetic acid cinnamyl ester (I) with 2-aminocrotonic acid 2-methoxyethyl ester (II) by heating at 120 °C.

………………..

http://www.google.com/patents/EP0161877A2?cl=en

AN EXAMPLE

Example 1

  • 3.51 g (10 mM) of 2-(3-nitrobenzylidene) acetoacetic acid cinnamyl ester were mixed with 1.38 g (12 mM) of 3-aminocrotonic acid methyl ester, and heated at 120°C for 3 hours. The reaction mixture was separated by silica gel column chromatography, and 3.00 g of cinnamyl methyl 4-(3-nitrophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate (trans) were obtained (yield 67%). This derivative was recrystallized once from methanol.
  • Elemental Analysis; C25H24N206

    • Calcd. (%) C: 66.95, H: 5.39, N: 6.25
    • Found (%) C: 67.03, H: 5.31, N: 6.20

(trans)

    • m.p.; 143.5-144.5°C
    • IR (cm-1); vNH 3370, νCO 1700, νNO2 1530, 1350
    • NMR δCDCl3; 2.34(s,6H), 3.60(s,3H), 4.69(d,2H), 5.13(s,lH), 6.14(tt,lH), 6.55(d,lH), 7.1-8.1(m,9H)

(cis)

    • m.p.; 136-137°C
    • IR (cm-1); vNH 3360, νCO 1700, 1650, νNO2 1530, 1350
    • NMR δCDCl3; 2.30(s,6H), 3,60(s,3H), 4.80(d,lH), 5.10(s,1H), 5.77(tt,lH), 6.56(d,1H), 6.64(bs,1H), 7.1-8.1(m,9H)

     

 EXAMPLE 13

 

  • Example 13 Cinnamyl 2-methoxyethyl 4-(3-nitrophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate
  • Elemental Analysis; C27H28N2O7

    • Calcd. (%) C: 65.84, H: 5.73, N: 5.69
    • Found (%) C: 65.88, H: 5.70, N: 5.66
    • m.p.; 115.5-116.5°C
    • IR (cm-1); vNH 3380, νCO 1710, 1680, νNO2 1530, 1350
    • NMR δCDCl3; 2.34(s,6H), 3.25(s,3H), 3.50(t,2H), 4.15(t,2H), 4.68(d,2H), 5.15(s,lH), 5.9-6.9(m,3H), 7.1-8.2(m,9H)

 

<br /><br /><br /> Cilnidipine<br /><br /><br /> pk_prod_list.xml_prod_list_card_pr?p_tsearch=A&p_id=131335<br /><br /><br />

cyclization of 2-(3-nitrobenzylidene)acetocetic acid cinnamyl ester (I) with 2-aminocrotonic acid 2-methoxyethyl ester (II) by heating at 120 C.

read more on dipine series………http://organicsynthesisinternational.blogspot.in/p/dipine-series.html

MORE

 

NMR

CARBOHYDRATE POLYMERS 90 PG 1719-1724 , YR2012

Numerous peaks were found in the spectrum of cilnidipine: 2.3555 (3H, s, CH3), 2.3886(3H, s, CH3), 3.2843(CD3OD), 3.3292(3H, s, OCH3), 3.5255–3.5623(2H, m, CH3OCH2CH2 ), 4.1224–4.1597(2H, m, CH3OCH2CH2 ), 4.6695–4.7293(2H, m, CH2 CH CH ), 4.8844(D2O), 5.1576(1H, s, CH), 6.2609(1H, dt, CH2 CH CH ), 6.5518(1H, d, CH2 CH CH ), 7.2488–7.3657(6H, m, ArH), 7.7002(1H, dd, ArH), 7.9805(1H, dd, ArH), 8.1548(1H, s, ArH)

CILNIDIPINE FT IR

 

CILNIDIPINE NMR

 

References: 

Dihydropyridine calcium channel blocker. Prepn: T. Kutsuma et al., EP 161877; eidem, US 4672068(1985, 1987 both to Fujirebio).

Pharmacology: K. Ikeda et al., Oyo Yakuri 44, 433 (1992).

 

Mechanism of action study: M. Hosonoet al., J. Pharmacobio-Dyn. 15, 547 (1992).

LC-MS determn in plasma: K. Hatada et al., J. Chromatogr. 583, 116 (1992). Clinical study: M. Ishii, Jpn. Pharmacol. Ther. 21, 59 (1993).

Acute toxicity study: S. Wada et al., Yakuri to Chiryo 20, Suppl. 7, S1683 (1992), C.A. 118, 32711 (1992).

read more on dipine series………http://organicsynthesisinternational.blogspot.in/p/dipine-series.html

U.S Patent No. 4,572,909 discloses amlodipine;

U.S Patent No. 4,446,325 discloses aranidipine;

U.S Patent No. 4,772,596 discloses azelnidipine;

U.S Patent No. 4,220,649 discloses barnidipine;

U.S Patent No. 4,448,964 discloses benidipine;

U.S Patent No. 5,856,346 discloses clevidipine;

U.S Patent No. 4,466,972 discloses isradipine;

U.S Patent No. 4,885,284 discloses efonidipine; and

U.S Patent No. 4,264,61 1 discloses felodipine.
read more on dipine series………http://organicsynthesisinternational.blogspot.in/p/dipine-series.html

  • Planar chemical structures of these calcium blockers of formula (I) are shown below.

    Figure 00070001
    Figure 00070002
    Figure 00070003
    Figure 00070004
    Figure 00070005
    Figure 00080001
    Figure 00080002
    Figure 00080003
    Figure 00080004
  • Amlodipine is 2-(2-aminoethoxymethyl)-4-(2-chlorophenyl)-3-ethoxycarbonyl-5-methoxycarbonyl-6-methyl-1,4-dihydropyridine disclosed in USP 4,572,909, Japanese patent publication No. Sho 58-167569 and the like.
  • Aranidipine is 3-(2-oxopropoxycarbonyl)-2,6-dimethyl-5-methoxycarbonyl-4-(2-nitrophenyl)-1,4-dihydropyridine disclosed in USP 4,446,325 and the like.
  • Azelnidipine is 2-amino-3-(1-diphenylmethyl-3-azetidinyloxycarbonyl)-5-isopropoxycarbonyl-6-methyl-4-(3-nitrophenyl)-1,4-dihydropyridine disclosed in USP 4,772,596, Japanese patent publication No. Sho 63-253082 and the like.
  • Barnidipine is 3-(1-benzyl-3-pyrrolidinyloxycarbonyl)-2,6-dimethyl-5-methoxycarbonyl-4-(3-nitrophenyl)-1,4-dihydropyridine disclosed in USP 4,220,649, Japanese patent publication No. Sho 55-301 and the like.
  • Benidipine is 3-(1-benzyl-3-piperidinyloxycarbonyl)-2,6-dimethyl-5-methoxycarbonyl-4-(3-nitrophenyl)-1,4-dihydropyridine and is described in the specifications of U.S. Patent No. 4,501,748, Japanese patent publication No. Sho 59-70667 and the like.
  • Cilnidipine is 2,6-dimethyl-5-(2-methoxyethoxycarbonyl)-4-(3-nitrophenyl)-3-(3-phenyl-2-propenyloxycarbonyl)-1,4-dihydropyridine disclosed in USP 4,672,068, Japanese patent publication No. Sho 60-233058 and the like.
  • Efonidipine is 3-[2-(N-benzyl-N-phenylamino)ethoxycarbonyl]-2,6-dimethyl-5-(5,5-dimethyl-1,3,2-dioxa-2-phosphonyl)-4-(3-nitrophenyl)-1,4-dihydropyridine disclosed in USP 4,885,284, Japanese patent publication No. Sho 60-69089 and the like.
  • Elgodipine is 2,6-dimethyl-5-isopropoxycarbonyl-4-(2,3-methylenedioxyphenyl)-3-[2-[N-methyl-N-(4-fluorophenylmethyl)amino]ethoxycarbonyl]-1,4-dihydropyridine disclosed in USP 4,952,592, Japanese patent publication No. Hei 1-294675 and the like.
  • Felodipine is 3-ethoxycarbonyl-4-(2,3-dichlorophenyl)-2,6-dimethyl-5-methoxycarbonyl-1,4-dihydropyridine disclosed in USP 4,264,611, Japanese patent publication No. Sho 55-9083 and the like.
  • Falnidipine is 2,6-dimethyl-5-methoxycarbonyl-4-(2-nitrophenyl)-3-(2-tetrahydrofurylmethoxycarbonyl)-1,4-dihydropyridine disclosed in USP 4,656,181, Japanese patent publication (kohyo) No. Sho 60-500255 and the like.
  • Lemildipine is 2-carbamoyloxymethyl-4-(2,3-dichlorophenyl)-3-isopropoxycarbonyl-5-methoxycarbonyl-6-methyl-1,4-dihydropyridine disclosed in Japanese patent publication No. Sho 59-152373 and the like.
  • Manidipine is 2,6-dimethyl-3-[2-(4-diphenylmethyl-1-piperazinyl)ethoxycarbonyl]-5-methoxycarbonyl-4-(3-nitrophenyl)-1,4-dihydropyridine disclosed in USP 4,892,875, Japanese patent publication No. Sho 58-201765 and the like.
  • Nicardipine is 2,6-dimethyl-3-[2-(N-benzyl-N-methylamino)ethoxycarbonyl]-5-methoxycarbonyl-4-(3-nitrophenyl)-1,4-dihydropyridine disclosed in USP 3,985,758, Japanese patent publication No. Sho 49-108082 and the like.
  • Nifedipine is 2,6-dimethyl-3,5-dimethoxycarbonyl-4-(2-nitrophenyl)-1,4-dihydropyridine disclosed in USP 3,485,847 and the like.
  • Nilvadipine is 2-cyano-5-isopropoxycarbonyl-3-methoxycarbonyl-6-methyl-4-(3-nitrophenyl)-1,4-dihydropyridine disclosed in USP 4,338,322, Japanese patent publication No. Sho 52-5777 and the like.
  • Nisoldipine is 2,6-dimethyl-3-isobutoxycarbonyl-5-methoxycarbonyl-4-(3-nitrophenyl)-1,4-dihydropyridine disclosed in USP 4,154,839, Japanese patent publication No. Sho 52-59161 and the like.
  • Nitrendipine is 3-ethoxycarbonyl-2,6-dimethyl-5-methoxycarbonyl-4-(3-nitrophenyl)-1,4-dihydropyridine disclosed in USP 3,799,934, Japanese patent publication (after examination) No. Sho 55-27054 and the like.
  • Pranidipine is 2,6-dimethyl-5-methoxycarbonyl-4-(3-nitrophenyl)-3-(3-phenyl-2-propen-1 -yloxycarbonyl)-1,4-dihydropyridine disclosed in USP 5,034,395, Japanese patent publication No. Sho 60-120861 and the like.

read more on dipine series………http://organicsynthesisinternational.blogspot.in/p/dipine-series.html

 

MAHABALIPURAM, INDIA

Mahabalipuram – Wikipedia, the free encyclopedia

en.wikipedia.org/wiki/Mahabalipuram

Mahabalipuram, also known as Mamallapuram is a town in Kancheepuram district in the Indian state of Tamil Nadu. It is around 60 km south from the city of …Shore Temple – ‎Seven Pagodas – ‎Pancha Rathas – ‎

Map of mahabalipuram.

.

Krishna’s Butter Ball in Mahabalipuram, India. The surface below the rock is …


http://www.weather-forecast.com/locations/Mamallapuram


Come to Mahabalipuram (also known as Mammallapuram), an enchanting beach that is located on the east coast of India.
Moonraikers Restaurant, Mamallapuram
 

Hotel Mamalla Bhavan – Mahabalipuram Chennai – Food, drink and entertainment

.

A carving at the Varaha Temple, Mahabalipuram

/////////////

FDA publishes List of Guidances planned for 2015


DR ANTHONY MELVIN CRASTO Ph.D's avatarDRUG REGULATORY AFFAIRS INTERNATIONAL

At the beginning of each year the FDA always publishes a list of the guidances it plans to publish during that year. It has done so again in 2015. The document is relatively comprehensive, containing five pages. Find out more about the Guidances the FDA plans on publishing in 2015.

http://www.gmp-compliance.org/enews_4660_FDA-publishes-List-of-Guidances-planned-for-2015_9293,9266,Z-QAMPP_n.html

At the beginning of each year the FDA always publishes a list of the guidances it plans to publish during that year. It has done so again in 2015. The document is relatively comprehensive, containing five pages. The list is subdivided into different categories. It contains for example also guidances planned in connection with the topics Clinical Pharmacology or Clinical/Statistical.

CGMP is a category of its own for which “only” three new guidances are planned for 2015:

  • A questions & answers (Q&A) paper on the topic data integrity
  • CGMP rules for outsourced facilities (pharmacy compounding)
  • Rules for the…

View original post 190 more words

GIVINOSTAT


Givinostat structure.svg

 

GIVINOSTAT, ITF2357, UNII-5P60F84FBH, ITF-2357, Gavinostat,
[6-(diethylaminomethyl)naphthalen-2-yl]methyl N-[4-(hydroxycarbamoyl)phenyl]carbamate,
diethyl-[6-(4-hydroxycarbamoyl-phenylcarbamoyloxymethyl)-naphthalen-2-yl-methyl]-amine
4-[6-(diethylaminomethyl)naphth-2-ylmethyloxycarbamoyl]benzohydroxamic acid
CAS 497833-27-9 FREE BASE
199657-29-9 HCL SALT
Molecular Formula: C24H27N3O4
Molecular Weight: 421.48888 g/mol
PHASE 2  Italfarmaco (INNOVATOR)
DESCRIBED IN U.S. Pat. No. 6,034,096 or in U.S. Pat. No. 7,329,689.

Givinostat.pngGIVINOSTAT

 

Givinostat (INN[1]) or gavinostat (originally ITF2357) is a histone deacetylase inhibitor with potential anti-inflammatory, anti-angiogenic, and antineoplastic activities.[2] It is a hydroxamate used in the form of its hydrochloride.

Givinostat is in numerous phase II clinical trials (including for relapsed leukemias and myelomas),[3] and has been granted orphan drug designation in the European Union for the treatment of systemic juvenile idiopathic arthritis[4] and polycythaemia vera.[5]

In 2010, orphan drug designation was assigned in the E.U. for the treatment of systemic-onset juvenile idiopathic arthritis and for the treatment of polycythemia vera. In 2013, this designation was assigned by the FDA for the treatment of Duchenne’s muscular dystrophy and for the treatment of Becker’s muscular dystrophy.

ITF2357 was discovered at Italfarmaco of Milan, Italy. It was patented in 1997 and first described in the scientific literature in 2005.[6][7]

Givinostat hydrochloride, an orally active, synthetic inhibitor of histone deacetylase, is being evaluated in several early clinical studies at Italfarmaco, including studies for the treatment of myeloproliferative diseases, polycythemia vera, Duchenne’s muscular dystrophy and periodic fever syndrome. The company was also conducting clinical trials for the treatment of Crohn’s disease and chronic lymphocytic leukemia; however, the trials were terminated.

No recent development has been reported for research into the treatment of juvenile rheumatoid arthritis, for the treatment of multiple myeloma and for the treatment of Hodgkin’s lymphoma.

Muscular dystrophies (MDs) include a heterogeneous group of genetic diseases invariably leading to muscle degeneration and impaired function. Mutation of nearly 30 genes gives rise to various forms of muscular dystrophy, which differ in age of onset, severity, and muscle groups affected (Dalkilic I, Kunkel LM. (2003) Muscular dystrophies: genes to pathogenesis. Curr. Opin. Genet. Dev. 13:231-238). The most common MD is the Duchenne muscular dystrophy (DMD), a severe recessive X-linked disease which affects one in 3,500 males, characterized by rapid progression of muscle degeneration, eventually leading to loss of ambulation and death within the second decade of life.

Attempts to replace or correct the mutated gene, by means of gene or cell therapy, might result in a definitive solution for muscular dystrophy, but this is not easy to achieve. Alternative strategies that prevent or delay muscle degeneration, reduce inflammation or promote muscle metabolism or regeneration might all benefit patients and, in the. future, synergize with gene or cell therapy. Steroids that reduce inflammation are currently the only therapeutic tool used in the majority of DMD patients (Cossu G, Sampaolesi M . (2007) New therapies for Duchenne muscular dystrophy: challenges, prospects and clinical trials. TRENDS Mol . Med. 13:520-526).

Diethyl- [ 6- ( 4-hydroxycarbamoyl-phenyl-carbamoyloxy- methyl ) -naphthalen-2-yl-methyl ] -ammonium chloride , which is described in WO 97/43251 (anhydrous form) and in WO 2004/065355 (monohydrate crystal form), herein both incorporated by reference, is an anti-inflammatory agent which is able to inhibit the synthesis of the majority of pro-inflammatory cytokines whilst sparing anti-inflammatory ones. Diethyl- [ 6- ( 4-hydroxycarbamoyl-phenyl-carbamoyloxy- methyl ) -naphthalen-2-yl-methyl ] -ammonium chloride is also known as ITF2357.

The monohydrate crystal form of diethyl- [ 6- ( 4- hydroxycarbamoyl-phenyl-carbamoyloxy-methy1 ) – naphthalen-2-yl-methyl ] -ammonium chloride is known as Givinostat .

Givinostat is being evaluated in several clinical studies, including studies for the treatment of myeloproliferative diseases, polycythemia vera, periodic fever syndrome, Crohn’s disease and systemic- onset juvenile idiopathic arthritis. Orphan drug designation was assigned in the E.U. for the treatment of systemic-onset juvenile idiopathic arthritis and for the treatment of polycythemia vera.

Givinostat has been recently found to act also as a Histone Deacetylase inhibitor (WO 2011/048514).

Histone deacetylases ( HDAC ) are a family of enzymes capable of removing the acetyl group bound to the lysine residues in the N-terminal portion of histones or in other proteins.

HDACs can be subdivided into four classes, on the basis of structural homologies. Class I HDACs (HDAC 1, 2, 3 and 8) are similar to the RPD3 yeast protein and are located in the cell nucleus. Class II HDACs (HDAC 4, 5, 6, 7, 9 and 10) are similar to the HDA1 yeast protein and are located both in the nucleus and in the cytoplasm. Class III HDACs are a structurally distinct form of NAD-dependent enzymes correlated with the SIR2 yeast protein. Class IV (HDAC 11) consists at the moment of a single enzyme having particular structural characteristics. The HDACs of classes I, II and IV are zinc enzymes and can be inhibited by various classes of molecule: hydroxamic acid derivatives, cyclic tetrapeptides , short-chain fatty acids, aminobenzamides , derivatives of electrophilic ketones, and the like. Class III HDACs are not inhibited by hydroxamic acids, and their inhibitors have structural characteristics different from those of the other classes .

The expression “histone deacetylase inhibitor” in relation to the present invention is to be understood as meaning any molecule of natural, recombinant or synthetic origin capable of inhibiting the activity of at least one of the enzymes classified as histone deacetylases of class I, class II or class IV.

Although HDAC inhibitors, as a class, are considered to be potentially useful as anti-tumor agents, it is worth to note that, till now, only two of them (Vorinostat and Romidepsin) have been approved as drugs for the cure of a single tumor form (Cutaneous T-cell lymphoma ) .

It is evident that the pharmaceutical properties of each HDAC inhibitor may be different and depend on the specific profile of inhibitory potency, relative to the diverse iso-enzymes as well as on the particular pharmacokinetic behaviour and tissue distribution.

Some HDAC inhibitors have been claimed to be potentially useful, in combination with other agents, for the treatment of DMD (WO 2003/033678, WO 2004/050076, Consalvi S. et al. Histone Deacetylase Inhibitors in the Treatment of Muscular Dystrophies: Epigenetic Drugs for Genetic Diseases. (2011) Mol. Med. 17 : 457-465 ) .

The potential therapeutic use of HDAC inhibitors in DMD may however be hampered by the possible harmful effects of these relatively toxic agents, especially when used for long-term therapies in paediatric patients .

Givinostat, as anti-inflammatory agent, has been already used in a phase II study in children with Systemic Onset Juvenile Idiopathic Arthritis; Givinostat administered at 1.5 mg/kg/day for twelve weeks achieved ACR Pedi 30, 50 and 70 improvement of approximately 70% (Vojinovic J, Nemanja D. (2011) HDAC Inhibition in Rheumatoid Arthritis and Juvenile Idiopathic Arthritis. Mol. Med 17:397-403) showing only a limited number of mild or moderate but short lasting, adverse effects.

To date more than 500 patients (including 29 children) have been treated with Givinostat. Repeated dose toxicity studies were carried out in dogs, rats and monkeys. Oral daily doses of the drug were administered up to nine consecutive months. The drug was well tolerated with no overt toxicity at high doses. The “no adverse effect levels” (NOAEL) ranged from 10 to 25 mg/kg/day depending on the animal species and the duration of treatment.

In juvenile animals Givinostat at 60 mg/kg/day did not affect the behavioural and physical development and reproductive performance of pups.

No genotoxic effect was detected for Givinostat in the mouse lymphoma assay and the chromosomal aberration assay in vitro and in the micronucleus test and UDS test in vivo.

Patent Submitted Granted
Monohydrate hydrochloride of the 4-hydroxycarbamoyl-phenyl)-carbamic acid (6-diethylaminomethyl-naphtalen-2-yl) ester [US7329689] 2005-11-03 2008-02-12

Adverse effects

In clinical trials of givinostat as a salvage therapy for advanced Hodgkin’s lymphoma, the most common adverse reactions were fatigue (seen in 50% of participants), mild diarrhea or abdominal pain (40% of participants), moderate thrombocytopenia (decreased platelet counts, seen in one third of patients), and mild leukopenia (a decrease in white blood cell levels, seen in 30% of patients). One-fifth of patients experienced prolongation of the QT interval, a measure of electrical conduction in the heart, severe enough to warrant temporary suspension of treatment.[8]

Mechanism of action

Givinostat inhibits class I and class II histone deacetylases (HDACs) and several pro-inflammatory cytokines. This reduces expression of tumour necrosis factor (TNF), interleukin 1α and β, and interleukin 6.[7]

It also has activity against cells expressing JAK2(V617F), a mutated form of the janus kinase 2 (JAK2) enzyme that is implicated in the pathophysiology of many myeloproliferative diseases, including polycythaemia vera.[9][10] In patients with polycythaemia, the reduction of mutant JAK2 concentrations by givinostat is believed to slow down the abnormal growth of erythrocytes and ameliorate the symptoms of the disease.[5]

………………….

PATENT

https://www.google.com/patents/WO2004065355A1?cl=en

Hydrochloride of (6-diethylaminomethyl-naphthalen-2-yl)- methyl ester of (4-hydroxycarbamoylphenyl)-carbamic acid (II)

has been described in US patent 6,034,096 as a derivative of hydroxamic acid having anti-inflammatory and immunosuppressive activity, probably owing to the ability thereof to inhibit the production of pro-inflammatory cyto ines. This compound is obtained according to

Example 12 of the above-mentioned patent as an anhydrous, amorphous, hygroscopic, deliquescent solid which is difficult to handle.

crystalline form of monohydrous hydrochloride of

(6-diethylaminomethyl-naphthalen-2-yl)-methyl ester of

(4~hydroxycarbamoylphenyl)-carbamic acid (I).

This form is particularly advantageous from the industrial perspective because it is stable and simpler to handle than the anhydrous and amorphous form described above.

………………

PATENT

http://www.google.co.in/patents/US7329689

Hydrochloride of (6-diethylaminomethyl-naphthalen-2-yl)-methyl ester of (4-hydroxycarbamoylphenyl)-carbamic acid (II)

has been described in U.S. Pat. No. 6,034,096 as a derivative of hydroxamic acid having anti-inflammatory and immunosuppressive activity, probably owing to the ability thereof to inhibit the production of pro-inflammatory cytokines. This compound is obtained according to Example 12 of the above-mentioned patent as an anhydrous, amorphous, hygroscopic, deliquescent solid which is difficult to handle.

The 4-(6-diethylaminomethyl-naphthalen-2-ylmethoxycarbonylamino)-benzoic acid can be prepared as described in Example 12, point C, of U.S. Pat. No. 6,034,096.

The acid (1.22 kg, 3 moles) was suspended in THF (19 l) and the mixture was agitated under nitrogen over night at ambient temperature. The mixture was then cooled to 0° C. and thionyl chloride (0.657 l, 9 moles) was added slowly, still under nitrogen, with the temperature being maintained below 10° C. The reaction mixture was heated under reflux for 60 minutes, DMF (26 ml) was added and the mixture was further heated under reflux for 60 minutes.

The solvent was evaporated under vacuum, toluene was added to the residue and was then evaporated. This operation was repeated twice, then the residue was suspended in THF (11.5 l) and the mixture was cooled to 0° C.

The mixture was then poured into a cold solution of hydroxylamine (50% aq., 1.6 l, 264 moles) in 5.7 l of water. The mixture was then cooled to ambient temperature and agitated for 30 minutes. 6M HCl was added until pH 2 was reached and the mixture was partially evaporated under vacuum in order to eliminate most of the THF. The solid was filtered, washed repeatedly with water and dissolved in a solution of sodium bicarbonate (2.5%, 12.2 l). The solution was extracted with 18.6 l of a mixture of THF and ethyl acetate (2:1 v/v). 37% HCl (130 ml) were added to the organic layer in order to precipitate the monohydrate of the (6-diethylaminomethyl-naphthalen-2-yl)-methyl ester hydrochloride of the (4-hydroxycarbamoyl-phenyl)-carbamic acid. If necessary, this operation can be repeated several times to remove any residues of the original acid.

Finally, the solid was dried under vacuum (approximately 30 mbar, 50° C.), producing 0.85 kg (60%) of compound (I).

HPLC purity: 99.5%; water content (Karl Fischer method): 3.8%; (argentometric) assay: 99.8%.

Elemental analysis
C % H % Cl % N %
Calculated for 60.56 6.35 7.45 8.83
C24H30ClN3O5
Found 61.06 6.48 7.48 8.90

 

…..

PATENT

http://www.google.co.in/patents/US20120302633

The hydrochloride of the (4-hydroxycarbamoyl-phenyl)-carbamic acid (6-dimethylamino methyl-2-naphtalenyl) ester, also known as ITF 2357 and having the International Non Proprietary Name (INN) of Givinostat® is an organic compound with immunosuppressive and anti-inflammatory activity,

…………………..

http://www.google.com/patents/US6034096

EXAMPLE 12

4-[6-(Diethylaminomethyl)naphth-2-ylmethyloxycarbamoyl]-benzohydroxamic acid hydrochloride

A. 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI) (22.2 g, 115 mmol) was added to a solution of 2,6-naphthalenedicarboxylic acid (25 g, 115 mmol) and hydroxybenzotriazole (15.6 g, 115 mmol) in dimethylformamide (1800 ml) and the mixture was stirred at room temperature for 2 hours. Diethyl amine (34.3 ml, 345 mmol) was added and the solution was stirred overnight at room temperature. The solvent was then evaporated under reduced pressure and the crude was treated with 1N HCl (500 ml) and ethyl acetate (500 ml), insoluble compounds were filtered off and the phases were separated. The organic phase was extracted with 5% sodium carbonate (3×200 ml) and the combined aqueous solutions were acidified with concentrated HCl and extracted with ethyl acetate (3×200 ml). The organic solution was then washed with 1N HCl (6×100 ml), dried over anhydrous sodium sulphate and the solvent was removed under reduced pressure yielding 18.5 g (Yield 60%) of pure 6-(diethylaminocarbonyl)-2-naphthalenecarboxylic acid; m.p.=122-124° C.

1 H-NMR d 8.67 (s, 1H), 8.25-8.00 (m, 4H), 7.56 (d, 1H), 3.60-3.20 (m, 4H), 1.30-1.00 (m, 6H).

B. A solution of 6-(diethylaminocarbonyl)-2- naphthalenecarboxylic acid (18 g, 66 mmol) in THF (200 ml) was slowly added to a refluxing suspension of lithium aluminium hydride (7.5 g, 199 mmol) in THF (500 ml). The mixture was refluxed for an hour, then cooled at room temperature and treated with a mixture of THF (25 ml) and water (3.5 ml), with 20% sodium hydroxide (8.5 ml) and finally with water (33 ml). The white solid was filtered off and the solvent was removed under reduced pressure. Crude was dissolved in diethyl ether (200 ml) and extracted with 1N HCl (3×100 ml). The aqueous solution was treated with 32% sodium hydroxide and extracted with diethyl ether (3×100 ml). The organic solution was dried over anhydrous sodium sulphate and the solvent was removed under reduced pressure yielding 12.7 g (79% yield) of pure 6-(diethylaminomethyl)-2-naphthalenemethanol as thick oil.

1 H-NMR d 7.90-7.74 (m, 4H), 7.49 (m, 2H), 5.32 (t, 1H, exchange with D2 O), 4.68 (d, 2H), 3.69 (s, 2H), 2.52 (q, 4H), 1.01 (t, 6H).

C. A solution of 6-(diethylaminomethyl)-2-naphthalene-methanol (12.5 g, 51 mmol) and N,N’-disuccinimidyl carbonate (13.2 g, 51 mmol) in acetonitrile (250 ml) was stirred at room temperature for 3 hours, then the solvent was removed and the crude was dissolved in THF (110 ml). This solution was added to a solution of 4-amino benzoic acid (7.1 g, 51 mmol) and sodium carbonate (5.5 g, 51 mmol) in water (200 ml) and THF (100 ml). The mixture was stirred overnight at room temperature, then THF was removed under reduced pressure and the solution was treated with 1N HCl (102 ml, 102 mmol). The precipitate was filtered, dried under reduced pressure, tritured in diethyl ether and filtered yielding 13.2 g (yield 64%) of pure 4-[6-(diethylaminomethyl)naphth-2-ylmethyloxycarbamoyl]-benzoic acid; m.p.=201-205° C. (dec.)

1 H-NMR d 10.26 (s, 1H), 8.13 (s, 1H), 8.05-7.75 (m, 6H), 7.63 (m, 3H), 5.40 (s, 2H), 4.32 (s, 2H), 2.98 (q, 4H), 1.24 (t, 6H).

D. A solution of 4-[6-(diethylaminomethyl)naphth-2-ylmethyloxycarbamoyl]benzoic acid (13.1 g, 32 mmol) and thionyl chloride (7 ml, 96 mmol) in chloroform (300 ml) was refluxed for 4 hours, then the solvent and thionyl chloride were evaporated. Crude was dissolved in chloroform (100 ml) and evaporated to dryness three times. Crude was added as solid to a solution of hydroxylamine hydrochloride (2.7 g, 39 mmol) and sodium bicarbonate (5.4 g, 64 mmol) and 1N sodium hydroxide (39 ml, 39 mmol) in water (150 ml) and THF (50 ml). The mixture was stirred overnight at room temperature, then THF was removed under reduced pressure and the aqueous phase was extracted with ethyl acetate (3×100 ml). The combined organic phases were dried over anhydrous sodium sulphate and the solvent was removed under reduced pressure. Crude was dissolved in THF and treated with a 1.5 N etheric solution of HCl. The solid product was filtered and dried yielding 6 g (yield 41%) of pure 4-[6-(diethylaminomethyl)naphth-2-ylmethyloxycarbamoyl]benzohydroxamic acid hydrochloride as white solid; m.p.=162-165° C., (dec.)

1 H-NMR d 11.24 (s, 1H, exchange with D2 O), 10.88 (s, 1H, exchange with D2 O), 10.16 (s, 1H), 8.98 (bs, 1H, exchange with D2 O), 8.21 (s, 1H), 8.10-7.97 (m, 3H), 7.89 (d, 1H), 7.80-7.55 (m, 5H), 5.39 (s, 2H), 4.48 (d, 2H), 3.09 (m, 4H), 1.30 (t, 6H).

http://www.molbase.com/

Some nmr predictions

CAS NO. 497833-27-9, [6-(diethylaminomethyl)naphthalen-2-yl]methyl N-[4-(hydroxycarbamoyl)phenyl]carbamate H-NMR spectral analysis

[6-(diethylaminomethyl)naphthalen-2-yl]methyl N-[4-(hydroxycarbamoyl)phenyl]carbamate NMR spectra analysis, Chemical CAS NO. 497833-27-9 NMR spectral analysis, [6-(diethylaminomethyl)naphthalen-2-yl]methyl N-[4-(hydroxycarbamoyl)phenyl]carbamate H-NMR spectrum

13 C NMR PREDICTIONS

 

 

[6-(diethylaminomethyl)naphthalen-2-yl]methyl N-[4-(hydroxycarbamoyl)phenyl]carbamate NMR spectra analysis, Chemical CAS NO. 497833-27-9 NMR spectral analysis, [6-(diethylaminomethyl)naphthalen-2-yl]methyl N-[4-(hydroxycarbamoyl)phenyl]carbamate C-NMR spectrum

 

COSY NMR…..http://www.nmrdb.org/

COSY NMR prediction (3)

HMBC /HSQC

HMBC, HSQC NMR prediction

References

 1

 

 

  1. Guerini V, Barbui V, Spinelli O, et al. (April 2008). “The histone deacetylase inhibitor ITF2357 selectively targets cells bearing mutated JAK2(V617F)”. Leukemia 22 (4): 740–7. doi:10.1038/sj.leu.2405049. PMID 18079739.

Further reading

US6034096 12 May 1997 7 Mar 2000 Italfarmaco S.P.A. Compounds with anti-inflammatory and immunosuppressive activities

 

WO1997043251A1 May 12, 1997 Nov 20, 1997 Italfarmaco Spa Compounds with anti-inflammatory and immunosuppressive activities
WO2004063146A1 Jan 7, 2004 Jul 29, 2004 Italfarmaco Spa Hydroxamic acid derivatives having anti-inflammatory action
WO2004065355A1 Jan 8, 2004 Aug 5, 2004 Italfarmaco Spa Monohydrate hydrochloride of the 4-hydroxycarbamoyl-phenyl)-carbamic acid (6-diethylaminomethyl-naphtalen-2-yl) ester
WO2006003068A2 Jun 7, 2005 Jan 12, 2006 Italfarmaco Spa Alpha-amino acid derivatives with antiinflammatory activity
WO2008097654A1 Feb 8, 2008 Aug 14, 2008 Nancie M Archin Methods of using saha for treating hiv infection
Citing Patent Filing date Publication date Applicant Title
US8518988 * 3 Dec 2010 27 Aug 2013 Chemi Spa Polymorph of the hydrochloride of the (4-hydroxycarbamoyl-phenyl)-carbamic acid (6-dimethylamino methyl-2-naphthalenyl) ester
US20120302633 * 3 Dec 2010 29 Nov 2012 Chemi Spa Novel polymorph of the hydrochloride of the (4-hydroxycarbamoyl-phenyl)-carbamic acid (6-dimethylamino methyl-2-naphthalenyl) ester
WO2011092556A1 3 Dec 2010 4 Aug 2011 Chemi Spa Novel polymorph of the hydrochloride of the (4-hydroxycarbamoyl-phenyl)-carbamic acid (6-dimethylamino methyl-2-naphtalenyl) ester
Givinostat
Givinostat structure.svg
Systematic (IUPAC) name
{6-[(diethylamino)methyl]naphthalen-2-yl}methyl [4-(hydroxycarbamoyl)phenyl]carbamate
Clinical data
Legal status
Routes Oral
Identifiers
CAS number 497833-27-9 Yes
ATC code None
PubChem CID 9804992
ChemSpider 7980752 
UNII 5P60F84FBH Yes
Chemical data
Formula C24H27N3O4 
Molecular mass 421.489 g/mol
 
Italfarmaco S.p.A.
Logo
Stato Italia Italia
Tipo Società per azioni
Fondazione 1938 a Milano
Fondata da Gastone De Santis
Sede principale Milano
Filiali Spagna SpagnaPortogallo Portogallo
Grecia GreciaRussia Russia
Cile CileBrasile Brasile
Turchia Turchia
Persone chiave Francesco De Santis, [Presidente Holding]
Settore sanità
Prodotti Farmaci
Fatturato >500 milioni di Euro (gruppo) (2011)
Dipendenti >1900 (gruppo) (2011)
Sito web www.italfarmaco.com

MILAN ITALY

FAVIPIRAVIR, ファビピラビル


 

FAVIPIRAVIR
Toyama (Originator)
RNA-Directed RNA Polymerase (NS5B) Inhibitors
Chemical Formula:   C5H4FN3O2
CAS #:   259793-96-9
Molecular Weight:   157.1
   

ANTI-INFLUENZA COMPOUND

clinical trials    http://clinicaltrials.gov/search/intervention=Favipiravir
Chemical Name:   6-fluoro-3-hydroxy-2-pyrazinecarboxamide
     
Synonyms:   T-705, T705, Favipiravir

ChemSpider 2D Image | favipiravir | C5H4FN3O2

  • Molecular FormulaC5H4FN3O2
  • Average mass157.103 Da
259793-96-9 [RN]
2-Pyrazinecarboxamide, 6-fluoro-3,4-dihydro-3-oxo-
 
6-Fluoro-3-hydroxypyrazine-2-carboxamide
6-Fluoro-3-oxo-3,4-dihydro-2-pyrazinecarboxamide
 
8916
Avigan

ファビピラビル
Favipiravir

6-Fluoro-3-hydroxypyrazine-2-carboxamide

C5H4FN3O2 : 157.1
[259793-96-9]

https://www.pmda.go.jp/files/000210319.pdf

 

The drug substance is a white to light yellow powder. It is sparingly soluble in acetonitrile and in methanol, and slightly soluble in water and in ethanol (99.5). It is slightly soluble at pH 2.0 to 5.5 and sparingly soluble at pH 5.5 to 6.1. The drug substance is not hygroscopic at 25°C/51% to 93%RH. The melting point is 187°C to 193°C, and the dissociation constant (pKa) is 5.1 due to the hydroxyl group of favipiravir. Measurement results on the partition ratio of favipiravir in water/octanol at 25°C indicate that favipiravir tends to be distributed in the 1-octanol phase at pH 2 to 4 and in the water phase at pH 5 to 13.

Any batch manufactured by the current manufacturing process is in Form A. The stability study does not show any change in crystal form over time; and a change from Form A to Form B is unlikely.

Experimental Properties

PROPERTY VALUE SOURCE
melting point (°C) 187℃ to 193℃ https://www.pmda.go.jp/files/000210319.pdf
water solubility slightly soluble in water https://www.pmda.go.jp/files/000210319.pdf
pKa 5.1 https://www.pmda.go.jp/files/000210319.pdf
 
T-705 is an RNA-directed RNA polymerase (NS5B) inhibitor which has been filed for approval in Japan for the oral treatment of influenza A (including avian and H1N1 infections) and for the treatment of influenza B infection.
The compound is a unique viral RNA polymerase inhibitor, acting on viral genetic copying to prevent its reproduction, discovered by Toyama Chemical. In 2005, Utah State University carried out various studies under its contract with the National Institute of Allergy and Infectious Diseases (NIAID) and demonstrated that T-705 has exceptionally potent activity in mouse infection models of H5N1 avian influenza.
T-705 (Favipiravir) is an antiviral pyrazinecarboxamide-based, inhibitor of of the influenza virus with an EC90 of 1.3 to 7.7 uM (influenza A, H5N1). EC90 ranges for other influenza A subtypes are 0.19-1.3 uM, 0.063-1.9 uM, and 0.5-3.1 uM for H1N1, H2N2, and H3N2, respectively. T-705 also exhibits activity against type B and C viruses, with EC90s of 0.25-0.57 uM and 0.19-0.36 uM, respectively. (1) Additionally, T-705 has broad activity against arenavirus, bunyavirus, foot-and-mouth disease virus, and West Nile virus with EC50s ranging from 5 to 300 uM.
Studies show that T-705 ribofuranosyl triphosphate is the active form of T-705 and acts like purines or purine nucleosides in cells and does not inhibit DNA synthesis
In 2012, MediVector was awarded a contract from the U.S. Department of Defense’s (DOD) Joint Project Manager Transformational Medical Technologies (JPM-TMT) to further develop T-705 (favipiravir), a broad-spectrum therapeutic against multiple influenza viruses.
Several novel anti-influenza compounds are in various phases of clinical development. One of these, T-705 (favipiravir), has a mechanism of action that is not fully understood but is suggested to target influenza virus RNA-dependent RNA polymerase. We investigated the mechanism of T-705 activity against influenza A (H1N1) viruses by applying selective drug pressure over multiple sequential passages in MDCK cells. We found that T-705 treatment did not select specific mutations in potential target proteins, including PB1, PB2, PA, and NP. Phenotypic assays based on cell viability confirmed that no T-705-resistant variants were selected. In the presence of T-705, titers of infectious virus decreased significantly (P < 0.0001) during serial passage in MDCK cells inoculated with seasonal influenza A (H1N1) viruses at a low multiplicity of infection (MOI; 0.0001 PFU/cell) or with 2009 pandemic H1N1 viruses at a high MOI (10 PFU/cell). There was no corresponding decrease in the number of viral RNA copies; therefore, specific virus infectivity (the ratio of infectious virus yield to viral RNA copy number) was reduced. Sequence analysis showed enrichment of G→A and C→T transversion mutations, increased mutation frequency, and a shift of the nucleotide profiles of individual NP gene clones under drug selection pressure. Our results demonstrate that T-705 induces a high rate of mutation that generates a nonviable viral phenotype and that lethal mutagenesis is a key antiviral mechanism of T-705. Our findings also explain the broad spectrum of activity of T-705 against viruses of multiple families.

Favipiravir, also known as T-705Avigan, or favilavir is an antiviral drug being developed by Toyama Chemical (Fujifilm group) of Japan with activity against many RNA viruses. Like certain other experimental antiviral drugs (T-1105 and T-1106), it is a pyrazinecarboxamide derivative. In experiments conducted in animals Favipiravir has shown activity against influenza virusesWest Nile virusyellow fever virusfoot-and-mouth disease virus as well as other flavivirusesarenavirusesbunyaviruses and alphaviruses.[1]Activity against enteroviruses[2] and Rift Valley fever virus has also been demonstrated.[3] Favipiravir has showed limited efficacy against Zika virus in animal studies, but was less effective than other antivirals such as MK-608.[4] The agent has also shown some efficacy against rabies,[5] and has been used experimentally in some humans infected with the virus.[6]

In February 2020 Favipiravir was being studied in China for experimental treatment of the emergent COVID-19 (novel coronavirus)disease.[7][8] On March 17 Chinese officials suggested the drug had been effective in treating COVID in Wuhan and Shenzhen.[9][10]

Discovered by Toyama Chemical Co., Ltd. in Japan, favipiravir is a modified pyrazine analog that was initially approved for therapeutic use in resistant cases of influenza.7,9 The antiviral targets RNA-dependent RNA polymerase (RdRp) enzymes, which are necessary for the transcription and replication of viral genomes.7,12,13

Not only does favipiravir inhibit replication of influenza A and B, but the drug shows promise in the treatment of influenza strains that are resistant to neuramidase inhibitors, as well as avian influenza.9,19 Favipiravir has been investigated for the treatment of life-threatening pathogens such as Ebola virus, Lassa virus, and now COVID-19.10,14,15

Mechanism of action

The mechanism of its actions is thought to be related to the selective inhibition of viral RNA-dependent RNA polymerase.[11] Other research suggests that favipiravir induces lethal RNA transversion mutations, producing a nonviable viral phenotype.[12] Favipiravir is a prodrug that is metabolized to its active form, favipiravir-ribofuranosyl-5′-triphosphate (favipiravir-RTP), available in both oral and intravenous formulations.[13][14] Human hypoxanthine guanine phosphoribosyltransferase (HGPRT) is believed to play a key role in this activation process.[15] Favipiravir does not inhibit RNA or DNA synthesis in mammalian cells and is not toxic to them.[1] In 2014, favipiravir was approved in Japan for stockpiling against influenza pandemics.[16] However, favipiravir has not been shown to be effective in primary human airway cells, casting doubt on its efficacy in influenza treatment.[17]

Approval status

In 2014, Japan approved Favipiravir for treating viral strains unresponsive to current antivirals.[18]

In March 2015, the US Food and Drug Administration completed a Phase III clinical trial studying the safety and efficacy of Favipiravir in the treatment of influenza.[19]

Ebola virus trials

Some research has been done suggesting that in mouse models Favipiravir may have efficacy against Ebola. Its efficacy against Ebola in humans is unproven.[20][21][22] During the 2014 West Africa Ebola virus outbreak, it was reported that a French nurse who contracted Ebola while volunteering for MSF in Liberia recovered after receiving a course of favipiravir.[23] A clinical trial investigating the use of favipiravir against Ebola virus disease was started in Guéckédou, Guinea, during December 2014.[24] Preliminary results showed a decrease in mortality rate in patients with low-to-moderate levels of Ebola virus in the blood, but no effect on patients with high levels of the virus, a group at a higher risk of death.[25] The trial design has been criticised by Scott Hammer and others for using only historical controls.[26] The results of this clinical trial were presented in February 2016 at the annual Conference on Retroviruses and Opportunistic Infections (CROI) by Daouda Sissoko[27] and published on March 1, 2016 in PLOS Medicine.[28]

SARS-CoV-2 virus disease

In March 2020, Chinese officials suggested Favipiravir may be effective in treating COVID-19.[29]

SYN

https://link.springer.com/article/10.1007/s11696-018-0654-9

Image result for FAVIPIRAVIR SYNTHESIS

Image result for FAVIPIRAVIR SYNTHESIS

Electronic supplementary material

 

Below is the link to the electronic supplementary material.

Supplementary material 1 (DOCX 1315 kb)

Ref

https://pdfs.semanticscholar.org/be8e/cb882b99204983d2f60077c7ab8b53f4d62c.pdf

Drug Discoveries & Therapeutics. 2014; 8(3):117-120.

As a RNA polymerase inhibitor, 6-fluoro-3-hydroxypyrazine-2-carboxamide commercially named favipiravir has been proved to have potent inhibitory activity against RNA viruses in vitro and in vivo. A four-step synthesis of the compound is described in this article, amidation, nitrification, reduction and fluorination with an overall yield of about 8%. In addition, we reported the crystal structure of the title compound. The molecule is almost planar and the intramolecular O−H•••O hydrogen bond makes a 6-member ring. In the crystal, molecules are packing governed by both hydrogen bonds and stacking interactions.

2.2.1. Preparation of 3-hydroxypyrazine-2-carboxamide To a suspension of 3-hydroxypyrazine-2-carboxylic acid (1.4 g, 10 mmol) in 150 mL MeOH, SOCl2 was added dropwise at 40°C with magnetic stirring for 6 h resulting in a bright yellow solution. The reaction was then concentrated to dryness. The residue was dissolved in 50 mL 25% aqueous ammonia and stirred overnight to get a suspension. The precipitate was collected and dried. The solid yellow-brown crude product was recrystallization with 50 mL water to get the product as pale yellow crystals (1.1 g, 78%). mp = 263-265°C. 1 H-NMR (300 MHz, DMSO): δ 13.34 (brs, 1H, OH), 8.69 (s, 1H, pyrazine H), 7.93-8.11 (m, 3H, pyrazine H, CONH2). HRMS (ESI): m/z [M + H]+ calcd for C5H6N3O2 + : 140.0460; found: 140.0457.

2.2.2. Preparation of 3-hydroxy-6-nitropyrazine-2- carboxamide In the solution of 3-hydroxypyrazine-2-carboxamide (1.0 g, 7 mmol) in 6 mL concentrate sulfuric acid under ice-cooling, potassium nitrate (1.4 g, 14 mmol) was added. After stirring at 40°C for 4 h, the reaction mixture was poured into 60 mL water. The product was collected by fi ltration as yellow solid (0.62 g, 48%). mp = 250-252°C. 1 H-NMR (600 MHz, DMSO): δ 12.00- 15.00 (br, 1H, OH), 8.97 (s, 1H, pyrazine H), 8.32 (s, 1H, CONH2), 8.06 (s, 1H, CONH2). 13C-NMR (75 MHz, DMSO): δ 163.12, 156.49, 142.47, 138.20, 133.81. HRMS (ESI): m/z [M + H]+ calcd for C5H5N4O4 + : 185.0311; found: 185.0304.

2.2.3. Preparation of 6-amino-3-hydroxypyrazine-2- carboxamide 3-Hydroxy-6-nitropyrazine-2-carboxamide (0.6 g, 3.3 mmol) and a catalytic amount of raney nickel were suspended in MeOH, then hydrazine hydrate was added dropwise. The resulting solution was refl uxed 2 h, cooled, filtered with diatomite, and then MeOH is evaporated in vacuo to get the crude product as dark brown solid without further purification (0.4 g, 77%). HRMS (ESI): m/z [M + H]+ calcd for C5H7N4O2 + : 155.0569; found:155.0509.

2.2.4. Preparation of 6-fluoro-3-hydroxypyrazine-2- carboxamide To a solution of 6-amino-3-hydroxypyrazine-2- carboxamide (0.4 g, 2.6 mmol) in 3 mL 70% HFpyridine aqueous at -20°C under nitrogen atmosphere, sodium nitrate (0.35 g, 5.2 mmol) was added. After stirring 20 min, the solution was warmed to room temperature for another one hour. Then 20 mL ethyl acetate/water (1:1) were added, after separation of the upper layer, the aqueous phase is extracted with four 20 mL portions of ethyl acetate. The combined extracts are dried with anhydrous magnesium sulfate and concentrated to dryness to get crude product as oil. The crude product was purified by chromatography column as white solid (0.12 g, 30%). mp = 178-180°C. 1 H-NMR (600 MHz, DMSO): δ 12.34 (brs, 1H, OH), 8.31 (d, 1H, pyrazine H, J = 8.0 Hz), 7.44 (s, 1H, CONH2), 5.92 (s, 1H, CONH2). 13C-NMR (75 MHz, DMSO): δ 168.66, 159.69, 153.98, 150.76, 135.68. HRMS (ESI): m/z [M + H]+ calcd for C5H5FN3O2 + : 158.0366; found: 158.0360.

SEE

Chemical Papers (2019), 73(5), 1043-1051.

PAPER

Medicinal chemistry (Shariqah (United Arab Emirates)) (2018), 14(6), 595-603

http://www.eurekaselect.com/158990/article

PATENT

CN 107641106

PAPER

Chemical Papers (2017), 71(11), 2153-2158.

https://link.springer.com/article/10.1007%2Fs11696-017-0208-6

Image result for A practical and step-economic route to Favipiravir

Image result for A practical and step-economic route to Favipiravir

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Below is the link to the electronic supplementary material.

Supplementary material 1 (DOCX 514 kb)

References

  1.  Furuta, Y.; Takahashi, K.; Shiraki, K.; Sakamoto, K.; Smee, D. F.; Barnard, D. L.; Gowen, B. B.; Julander, J. G.; Morrey, J. D. (2009). “T-705 (favipiravir) and related compounds: Novel broad-spectrum inhibitors of RNA viral infections”. Antiviral Research 82 (3): 95–102. doi:10.1016/j.antiviral.2009.02.198PMID 19428599edit
  2. WO 2000010569
  3. WO 2008099874
  4. WO 201009504
  5. WO 2010104170
  6. WO 2012063931

Process route
OH
OH
hydrolysis
CLIP
Influenza virus is a central virus of the cold syndrome, which has attacked human being periodically to cause many deaths amounting to tens millions. Although the number of deaths shows a tendency of decrease in the recent years owing to the improvement in hygienic and nutritive conditions, the prevalence of influenza is repeated every year, and it is apprehended that a new virus may appear to cause a wider prevalence.
For prevention of influenza virus, vaccine is used widely, in addition to which low molecular weight substances such as Amantadine and Ribavirin are also used

CLIP

Synthesis of Favipiravir
ZHANG Tao1, KONG Lingjin1, LI Zongtao1,YUAN Hongyu1, XU Wenfang2*
(1. Shandong Qidu PharmaceuticalCo., Ltd., Linzi 255400; 2. School of Pharmacy, Shandong University, Jinan250012)
ABSTRACT: Favipiravir was synthesized from3-amino-2-pyrazinecarboxylic acid by esterification, bromination with NBS,diazotization and amination to give 6-bromo-3-hydroxypyrazine-2-carboxamide,which was subjected to chlorination with POCl3, fluorination with KF, andhydrolysis with an overall yield of about 22%.

PATENT
US6787544

Figure US06787544-20040907-C00005

subs            G1 G2 G3 G4 R2
    compd 32 N CH C—CF3 N H

…………………
EP2192117
Figure US20100286394A1-20101111-C00001
Example 1-1

Figure US20100286394A1-20101111-C00002

To a 17.5 ml N,N-dimethylformamide solution of 5.0 g of 3,6-difluoro-2-pyrazinecarbonitrile, a 3.8 ml water solution of 7.83 g of potassium acetate was added dropwise at 25 to 35° C., and the solution was stirred at the same temperature for 2 hours. 0.38 ml of ammonia water was added to the reaction mixture, and then 15 ml of water and 0.38 g of active carbon were added. The insolubles were filtered off and the filter cake was washed with 11 ml of water. The filtrate and the washing were joined, the pH of this solution was adjusted to 9.4 with ammonia water, and 15 ml of acetone and 7.5 ml of toluene were added. Then 7.71 g of dicyclohexylamine was added dropwise and the solution was stirred at 20 to 30° C. for 45 minutes. Then 15 ml of water was added dropwise, the solution was cooled to 10° C., and the precipitate was filtered and collected to give 9.44 g of dicyclohexylamine salt of 6-fluoro-3-hydroxy-2-pyradinecarbonitrile as a lightly yellowish white solid product.
1H-NMR (DMSO-d6) δ values: 1.00-1.36 (10H, m), 1.56-1.67 (2H, m), 1.67-1.81 (4H, m), 1.91-2.07 (4H, m), 3.01-3.18 (2H, m), 8.03-8.06 (1H, m), 8.18-8.89 (1H, broad)
Example 1-2
4.11 ml of acetic acid was added at 5 to 15° C. to a 17.5 ml N,N-dimethylformamide solution of 5.0 g of 3,6-difluoro-2-pyrazinecarbonitrile. Then 7.27 g of triethylamine was added dropwise and the solution was stirred for 2 hours. 3.8 ml of water and 0.38 ml of ammonia water were added to the reaction mixture, and then 15 ml of water and 0.38 g of active carbon were added. The insolubles were filtered off and the filter cake was washed with 11 ml of water. The filtrate and the washing were joined, the pH of the joined solution was adjusted to 9.2 with ammonia water, and 15 ml of acetone and 7.5 ml of toluene were added to the solution, followed by dropwise addition of 7.71 g of dicyclohexylamine. Then 15 ml of water was added dropwise, the solution was cooled to 5° C., and the precipitate was filtered and collected to give 9.68 g of dicyclohexylamine salt of 6-fluoro-3-hydroxy-2-pyrazinecarbonitrile as a slightly yellowish white solid product.
Examples 2 to 5
The compounds shown in Table 1 were obtained in the same way as in Example 1-1.

TABLE 1
 
Figure US20100286394A1-20101111-C00003
 
Example No. Organic amine Example No. Organic amine
 
2 Dipropylamine 4 Dibenzylamine
3 Dibutylamine 5 N-benzylmethylamine
 

Dipropylamine salt of 6-fluoro-3-hydroxy-2-pyrazinecarbonitrile
1H-NMR (DMSO-d6) 6 values: 0.39 (6H, t, J=7.5 Hz), 1.10 (4H, sex, J=7.5 Hz), 2.30-2.38 (4H, m), 7.54 (1H, d, J=8.3 Hz)
Dibutylamine salt of 6-fluoro-3-hydroxy-2-pyrazinecarbonitrile
1H-NMR (DMSO-d6) 6 values: 0.36 (6H, t, J=7.3 Hz), 0.81 (4H, sex, J=7.3 Hz), 0.99-1.10 (4H, m), 2.32-2.41 (4H, m), 7.53 (1H, d, J=8.3 Hz)
Dibenzylamine salt of 6-fluoro-3-hydroxy-2-pyrazinecarbonitrile
1H-NMR (DMSO-d6) δ values: 4.17 (4H, s), 7.34-7.56 (10H, m), 8.07 (1H, d, J=8.3 Hz)
N-benzylmethylamine salt of 6-fluoro-3-hydroxy-2-pyrazinecarbonitrile
1H-NMR (DMSO-d6) δ values: 2.57 (3H, s), 4.14 (2H, s), 7.37-7.53 (5H, m), 8.02-8.08 (1H, m)
Preparation Example 1

Figure US20100286394A1-20101111-C00004

300 ml of toluene was added to a 600 ml water solution of 37.5 g of sodium hydroxide. Then 150 g of dicyclohexylamine salt of 6-fluoro-3-hydroxy-2-pyrazinecarbonitrile was added at 15 to 25° C. and the solution was stirred at the same temperature for 30 minutes. The water layer was separated and washed with toluene, and then 150 ml of water was added, followed by dropwise addition of 106 g of a 30% hydrogen peroxide solution at 15 to 30° C. and one-hour stirring at 20 to 30° C. Then 39 ml of hydrochloric acid was added, the seed crystals were added at 40 to 50° C., and 39 ml of hydrochloric acid was further added dropwise at the same temperature. The solution was cooled to 10° C. the precipitate was filtered and collected to give 65.6 g of 6-fluoro-3-hydroxy-2-pyrazinecarboxamide as a slightly yellowish white solid.
1H-NMR (DMSO-d6) δ values: 8.50 (1H, s), 8.51 (1H, d, J=7.8 Hz), 8.75 (1H, s), 13.41 (1H, s)

CLIP
jan 2014

Investigational flu treatment drug has broad-spectrum potential to fight multiple viruses
First patient enrolled in the North American Phase 3 clinical trials for investigational flu treatment drug
BioDefense Therapeutics (BD Tx)—a Joint Product Management office within the U.S. Department of Defense (DoD)—announced the first patient enrolled in the North American Phase 3 clinical trials for favipiravir (T-705a). The drug is an investigational flu treatment candidate with broad-spectrum potential being developed by BD Tx through a contract with Boston-based MediVector, Inc.
Favipiravir is a novel, antiviral compound that works differently than anti-flu drugs currently on the market. The novelty lies in the drug’s selective disruption of the viralRNA replication and transcription process within the infected cell to stop the infection cycle.
“Favipiravir has proven safe and well tolerated in previous studies,” said LTC Eric G. Midboe, Joint Product Manager for BD Tx. “This first patient signifies the start of an important phase in favipiravir’s path to U.S. Food and Drug Administration (FDA) approval for flu and lays the groundwork for future testing against other viruses of interest to the DoD.”
In providing therapeutic solutions to counter traditional, emerging, and engineered biological threats, BD Tx chose favipiravir not only because of its potential effectiveness against flu viruses, but also because of its demonstrated broad-spectrum potential against multiple viruses.  In addition to testing favipiravir in the ongoing influenzaprogram, BD Tx is testing the drug’s efficacy against the Ebola virus and other viruses considered threats to service members. In laboratory testing, favipiravir was found to be effective against a wide variety of RNA viruses in infected cells and animals.
“FDA-approved, broad-spectrum therapeutics offer the fastest way to respond to dangerous and potentially lethal viruses,” said Dr. Tyler Bennett, Assistant Product Manager for BD Tx.
MediVector is overseeing the clinical trials required by the  FDA  to obtain drug licensure. The process requires safety data from at least 1,500 patients treated for flu at the dose and duration proposed for marketing of the drug. Currently, 150 trial sites are planned throughout the U.S.
SOURCE BioDefense Therapeutics
 
Malpani Y, Achary R, Kim SY, Jeong HC, Kim P, Han SB, Kim M, Lee CK, Kim JN, Jung YS.
Eur J Med Chem. 2013 Apr;62:534-44. doi: 10.1016/j.ejmech.2013.01.015. Epub 2013 Jan 29.

 

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  17. Nature Biotechnology: Coronavirus puts drug repurposing on the fast track [Link]
  18. Pharmaceuticals and Medical Devices Agency: Avigan (favipiravir) Review Report [Link]
  19. World Health Organization: Influenza (Avian and other zoonotic) [Link]
Favipiravir
Favipiravir.svg
Names
IUPAC name

 

5-Fluoro-2-hydroxypyrazine-3-carboxamide
Other names

 

T-705; Avigan; favilavir
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
PubChem CID
UNII
Properties
C5H4FN3O2
Molar mass 157.104 g·mol−1
Pharmacology
J05AX27 (WHO)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

////////////

 

ANTHONY MELVIN CRASTO

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PALINAVIR


PALINAVIR, BILA-2011-BS

UNII-632S1WU9Z2, 154612-39-2, n-[(1s)-1-[[(1s,2r)-1-benzyl-3-[(2s,4r)-2-(tert-butylcarbamoyl)-4-(4-pyridylmethoxy)piperidino]-2-hydroxypropyl]carbamoyl]-2-methylpropyl]quinaldamide,
N-[(2S)-1-[[(2S,3R)-4-[(2S,4R)-2-(tert-butylcarbamoyl)-4-(pyridin-4-ylmethoxy)piperidin-1-yl]-3-hydroxy-1-phenylbutan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]quinoline-2-carboxamide
Molecular Formula:C41H52N6O5
Molecular Weight:708.88878 g/mol
Patent Submitted Granted
Substituted pipecolinic acid derivatives as HIV protease inhibitors [US5614533] 1997-03-25
Substituted pipecolinic acid derivatives as HIV protease inhibitors. [EP0560268] 1993-09-15 1995-01-04

……………………….

PATENT

http://www.google.com/patents/WO2013105118A1?cl=en

Scheme 5: Synthesis of Palinavir (6):

Figure imgf000018_0002

The organic solvent mentioned according to the invention is selected from the group consisting of organic solvents, wherein the organic solvents are polar aprotic such as DCM, THF, Ethyl acetate, acetone, DMF, acetonitrile, DMSO ; polar protic solvents such as lower alcohol particularly (C1-C6) alkyl alcohol, water, acetic acid ; non-polar solvents such as hexane, benzene, toluene, chloroform, pet. ether, 1,4-dioxane, heptane either alone or mixtures thereof . Additionally the purification or separation of crude product can be accomplished by known techniques viz. extraction, column chromatography in a suitable organic solvent with the aid of instruments such as TLC, HPLC, GC, mass spectroscopy, or distillation, crystallization, derivatization.

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………………………….

J Org Chem 1997,62(11),3440

The reaction of tert-butoxycarbonyl-L-phenylalanine (I) with isobutyl chloroformate in THF gives the expected mixed anhydride which is treated with diazomethane and HCl yielding the corresponding chloromethyl ketone (II). The reduction of (II) with NaBH4 in THF affords the (S)-chlorohydrin (IV), which is treated with KOH in ethanol to obtain the chiral epoxide (V)(1,2). Ring opening of (V) with (?(cis)-N-tert-butyl-4-(4-pyridylmethoxy)piperidine-2-carboxamide (VI) by a treatment with LiCl in refluxing ethanol gives a mixture of diastereomers that is separated by chromatography giving the pure isomer (VII). The reaction of (VII) with tert-butoxycarbonyl-L-valine (VIII) by treatment first with trifluoroacetic acid (TFA), and condesation by means of BOP ((benzotriazol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate) and NMM (N-methylmorpholine) affords the expected condensation product (IX). Finally, this compound is condensed with quinoline-2-carboxylic acid (X) by means of BOP and NMM as before. 2) The piperidine (VI) has been obtained by condensation of (?(cis)-N-(tert-butoxycarbonyl)-4-hydroxypiperidine-2-carboxamide (XI) with 4-(chloromethyl)pyridine (XII) by means of NaH in DMS, followed by hydrolysis with HCl.

Palinavir can also be obtained as follows: The controlled oxidation of 2(S)-(dibenzylamino)-3-phenyl-1-propanol (XIII) with pyridine-SO3 complex in DMSO gives the corresponding aldehyde (XIV), which is condensed with bromochloromethane (XV) by means of Li in THF followed by hydrolysis with HCl yielding regioselectively the 1-chloro-2-butanol (XVI). The debenzylation of (XVI) by hydrogenation over Pd/C affords the free amine (XVII), which is treated with tert-butoxycarbonyl anhydride/triethylamine and dehydrochlorinated with KOH in methanol to give the desired chiral epoxide (V).

The chiral piperidine (2S,4R)(VI) has been obtained as follows: The cyclization of 3-buten-1-ol (XXII) with (S)-1-phenylethylamine (XXIII) and glyoxylic acid (XXIV) by means of tosyl chloride in THF gives a mixture of the (2S,4R) and (2R,4S) lactones (XXV), which is resolved by fractional crystallyzation of their salts with the chiral camphorsulfonic acid (XXVI), followed by elimination of the acid with ammonia to afford (2S,4R)(XXVII). The reaction of lactone (XXVII) with isopropylmagnesium chloride and tert-butylamine in THF gives (2S,4R)-N-tert-butyl-4-hydroxy-1-(1(S)-phenylethyl)piperidine-2-carboxamide (XXVIII), which is debenzylated by hydrogenation and protected with tert-butoxycarbonyl anhydride yielding (2S,4R)-N-(tert-butoxycarbonyl)-4-hydroxypiperidine-2-carboxamide (2S,4R)(XI), which is finally condensed with 4-(chloromethyl)pyridine (XII) as before to obtain the chiral piperidine (2S,4R)(VI), already reported.

The condendsation of epoxide (V) with (2S,4R)(VI) by means of basic alumina in THF, followed by elimination of the protecting group with HCl and NaOH yields directly the condensation product (XVIII) as a pure diastereomer and with a free amino group. Finally, this compound is condensed with N-(2-quinolylcarbonyl)-L-valine (XIX) through its activation compound with isobutyl chloroformate (the 4(S)-isopropyl-2-(2-quinolyl)oxazol-5(4H)-one (XX)). The N-acyl-L-valine (XIX) has been obtained by acylation of L-valine (XXI) with quinoline-2-carboxylic acid (X) through its acyl chloride obtained with SOCl2.

………………………..

Palinavir is an inhibitor with five chiral centers. It contains the amino acid valine and pipecolinin acid. The previous way to create this drug faced three major obstacles. First, the reaction from 2 to 3 used diazomethane. Therefore, is is difficult, if not impossible, to produce large quantities. Secondly, the steps included in going from 4 to 5 gave way to racemers which is very inefficient. Finally, chromatography is needed at two separate times.

Four issues were addresses in route to product 1. First, because of the number of chiral centers, stereochemical control was a concern. high chemical yields were a second concern. Also, multi step procedures were advantageous to cut down on purification steps. Finally, the synthesis tried to restrict the use of hazardous reagents. The following retrosynthesis reaction was conceived and three target molecules were identified as seen in figure 1.

Molecule 3 uses a diaseteroselective addition of in situ (chloromethyl)lithium to N,N-dibenzylphenylalaninol and is derived from a four step process.

Recrystallization of 13 is required. Molecule 14 was not reached because it posed a problem later in the reaction. The N-benzyl protection group could not be removed to react with 9.

8 is a derivative of naturally occurring pipocolic acid, 16, named 3-buten-1-ol. Selective crystallization of diastereomeric salts can lead to 17a, but a more efficient way is by having a 60:40 mixture of lactones 17a,b. This leads to 18a,b using a Brodroux process. Crystallization of 18a,b lead to a poor overall yield. Instead, 18a,b undergoes salt crystallization with (-)-camphorsulfonic acid. Finally, 18a underwent hydrolysis and then addition of di-tert butyl dicarbonate leads to 8.

8 was then transformed to 5 in a three step process.

8 was added to NaOH and alkylated with 4-picolyl chloride. The protecting group was lost with the addition of acid. 

Derivation of 9 was started by a simple substitution of 19, quinoline-2-carboxylic acid, to 20, an acid chloride, with the help of thionyl chloride. Acylation of amino acid L-valine to 20 was accomplished by a biphasic system.

In the original synthesis of palinavir, a 2:1 mixture of 3 to 5 was needed to produce only ~35% of 6 and flash chromatography was needed. On a large scale without chromatography, 6 was produced with a 85% yield, but 21 was also produced. To keep the production of 21 to a minimum, the reaction was performed in a solution that was degassed. This insured that the pyridine ring would not react in the presence of air. With this precaution, only 1-2% of the yield was 21. A washing of the solution with 1 M KH2PO4 removed and left over 5. Deprotection was achieved with the addition of concentrated HCl and followed by adding NaOH. The product of 10 was a “viscous syrup”. 22 was 1-1.5% of the product and was not removed before the addition of 9 to form 80-85% palinavir.

Coupling of 10 and 9 is the final step in the synthesis , although there are still some purification steps left.

Two recrystallizations were required for the final 99.6% purity.

………………………..

J. Org. Chem., 1997, 62 (11), pp 3440–3448
DOI: 10.1021/jo9702655
Abstract Image

Palinavir is a potent peptidomimetic-based HIV protease inhibitor. We have developed a highly convergent and stereoselective synthesis which is amenable to the preparation of multikilogram quantities of this compound. The synthetic sequence proceeds in 24 distinct chemical steps (with several integrated, multistep operations) from commercially available starting materials. No chromatographies are required throughout the process, and the final product is purified by crystallization of its dihydrochloride salt to >99% homogeneity.

crude palinavir (1) as a thick brown oil (yield not determined). HPLC analysis (Supelcosil LZ-ABZ, 10−50% 1% TFA in MeCN/1% TFA in 25 min, 1 mL/min flow rate): 1, tR 17.80 min (84.1%); 24, tR 18.47 min (2.0%); 25, tR 19.97 min (1.45%).

palinavir dihydrochloride (1750 g, 51% yield) containing 0.25% w/w isopropanol (by 1H NMR):

mp 175−185 °C.

[α]25D −13.0° (c 1, MeOH). [α]25Hg365 +44.9° (c 1, MeOH).

IR (KBr) ν 3700−2300, 1660, 1555, 1520 cm-1.

1H NMR (DMSO-d6) δ 10.00 (broad s, 1H), 8.88 (d, J = 6.3 Hz, 2H), 8.61 (d, J = 8.4 Hz, 1H), 8.60 (s, 1H), 8.51 (d, J = 9.6 Hz, 1H), 8.35 (d, J = 8.7 Hz, 1H), 8.20 (d, J = 8.4 Hz, 1H), 8.16 (d, J = 8.7 Hz, 1H), 8.11 (d, J = 8.1 Hz, 1H), 7.94 (d, J = 6.0 Hz, 2H), 7.89 (t, J = 7.6 Hz, 1H), 7.74 (t, J = 7.5 Hz, 1H), 7.19 (d, J = 7.2 Hz, 2H), 7.08 (t, J = 7.5 Hz, 2H), 6.91 (t, J = 7.3 Hz, 1H), 4.86 (AB quartet, 2H), 4.37 (broad t, J = 7.8 Hz, 1H), 4.21 (d, J = 11.4 Hz, 1H), 4.11 (broad m, 1H), 3.96 (broad m, 1H), 3.80−3.65 (m, 2H), 3.26 (t, J = 7.4 Hz, 1H), 3.15−3.01 (m, 2H), 2.94 (broad d, J = 12.0 Hz, 1H), 2.62 (dd, J = 13.6, 10.6 Hz, 1H), 2.56 ((broad d, J = 12.0 Hz, 1H), 2.20−2.05 (m, 2H), 1.86 (m, 1H), 1.69 (q, J = 11.7 Hz, 1H), 1.31 (s, 9H), 0.81 (d, J = 6.3 Hz, 3H), 0.80 (d, J = 6.6 Hz, 3H).

13C NMR (DMSO-d6) δ 170.4, 166.4, 163.3, 158.3, 149.5, 145.9, 141.9, 138.6, 138.2, 130.7, 129.3, 129.1, 129.0, 128.3, 128.2, 128.0, 125.9, 124.1, 118.6, 72.3, 68.8, 67.2, 64.8, 58.0, 57.8, 54.4, 51.3, 51.1, 35.4, 34.1, 31.1, 28.2, 19.5, 17.9.

FAB-MS m/z 709 (MH+ of free base). Anal. Calcd for C41H54Cl2N6O5 (corrected for 8% water content as determined by Karl Fisher analysis and 0.25% w/w isopropanol as determined by 1H NMR):  C, 58.31; H, 7.29; N, 9.93. Found:  C, 57.76; H, 7.25; N, 9.89. Titration of HCl content using NaOH:  2.09 ± 0.03 mol HCl. HPLC homogeneity (Supelcosil LC-ABZ, 10−50% 1% TFA in MeCN/1% TFA in 25 min, 1 mL/min flow rate):  palinavir dihydrochloride, tR 18.24 min (99.51%); 25 tR 20.39 min (0.33%). HPLC homogeneity (Nova-Pak C8, 20−80% MeCN/50 mM NaH2PO4 in 25 min, 1 mL/min flow rate):  palinavir dihydrochloride, tR 15.52 min (99.67%); 25 tR 13.52 min (0.33%).

PURE palinavir (1) as a white amorphous powder (1902 g, 84% yield):

mp 100−107 °C. [α]25D −11.5° (c 1, MeOH).

IR (KBr) ν 3700−3100, 1660, 1520, 1495 cm-1.

1H NMR (CDCl3) δ 8.54 (d, J = 5.7 Hz, 2H), 8.48 (d, J = 8.6 Hz, 1H), 8.31 (d, J = 8.6 Hz, 1H, part of AB), 8.22 (d, J = 8.3 Hz, 1H, part of AB), 8.13 (d, J = 8.3 Hz, 1H), 7.90 (d, J = 8.0 Hz, 1H), 7.80 (t, J = 7.6 Hz, 1H), 7.65 (t, J = 7.6 Hz, 1H), 7.25 (d, J = 5.4 Hz, 2H), 7.13 (d, J = 7.3 Hz, 2H), 7.07 (t, J = 7.5 Hz, 1H), 6.92 (t, J = 7.3 Hz, 1H), 6.59 (d, J = 8.3 Hz, 1H), 6.57 (s, 1H), 4.61 (d, J = 13.4 Hz, 1H, part of AB), 4.51 (d, J = 13.4 Hz, 1H, part of AB), 4.32 (dd, J = 8.6, 6.4 Hz, 1H), 4.22 (m, 1H), 3.97 (m, 1), 3.47−3.33 (m, 2H), 2.94 (dd, J = 14.3, 4.1 Hz, 1H), 2.89 (d, J= 8.6 Hz, 1H), 2.79−2.72 (m, 1H), 2.77 (dd, J = 14.3, 10.8 Hz, 1H), 2.43 (dd, J = 13.4, 8.3 Hz, 1H), 2.40−2.25 (m, 3H), 1.95 (broad d, J = 12.4 Hz, 1H), 1.65 (q J = 11.8 Hz, 2H), 1.32 (s, 9H), 0.95 (d, J = 7.0 Hz, 3H), 0.83 (d, J = 6.7 Hz, 3H).

13C NMR (CDCl3) δ 171.6, 171.2, 165.0, 149.8, 148.8, 147.9, 146.5, 137.6, 137.5, 130.3, 129.9, 129.5, 129.4, 129.0, 128.8, 128.5, 128.2, 127.7, 126.4, 121.7, 118.8, 75.0, 71.9, 68.1, 66.7, 59.4, 56.9, 54.6, 50.9, 50.2, 34.8, 33.3, 29.8, 29.7, 28.7, 19.6, 17.5.

FAB-MS m/z 709 (MH+). Anal. Calcd for C41H52N6O5(corrected for 0.7% water content as determined by Karl Fisher analysis):  C, 68.98; H, 7.42; N, 11.77. Found:  C, 68.71; H, 7.47; N, 11.71. HPLC homogeneity (Supelcosil LC-ABZ, 10−50% 1% TFA in MeCN/1% TFA in 25 min, 1 mL/min flow rate):  palinavir (1), tR 17.83 min (99.59%); 25 tR20.00 min (0.41%). HPLC homogeneity (Nova-Pak C8, 10−80% MeCN/50 mM NaH2PO4 in 25 min, 1 mL/min flow rate):  palinavir (1), tR 17.37 min (99.51%); 25 tR 15.87 min (0.49%).

Reference
1 * ARUN K. GHOSH ET AL: “The Development of Cyclic Sulfolanes as Novel and High-Affinity P2 Ligands for HIV-1 Protease Inhibitors“, JOURNAL OF MEDICINAL CHEMISTRY, vol. 37, no. 8, 1 April 1994 (1994-04-01), pages 1177-1188, XP055057710, ISSN: 0022-2623, DOI: 10.1021/jm00034a016
2 * KAY BRICKMANN ET AL: “Synthesis of Conformationally Restricted Mimetics of [gamma]-Turns and Incorporation into Desmopressin, an Analogue of the Peptide Hormone Vasopressin“, CHEMISTRY – A EUROPEAN JOURNAL, vol. 5, no. 8, 2 August 1999 (1999-08-02), pages 2241-2253, XP055057517, ISSN: 0947-6539, DOI: 10.1002/(SICI)1521-3765(19990802)5:8<2241: :AID-CHEM2241>3.0.CO;2-L
3 * KIRAN I N C ET AL: “A concise enantioselective synthesis of (+)-goniodiol and (+)-8-methoxygoniodiol via Co-catalyzed HKR of anti-(2SR, 3RS)-3-methoxy-3-phenyl-1, 2-epoxypropane“, TETRAHEDRON LETTERS, ELSEVIER, AMSTERDAM, NL, vol. 52, no. 3, 19 January 2011 (2011-01-19), pages 438-440, XP027558447, ISSN: 0040-4039 [retrieved on 2010-12-14]
4 * M. TOKUNAGA: “Asymmetric Catalysis with Water: Efficient Kinetic Resolution of Terminal Epoxides by Means of Catalytic Hydrolysis“, SCIENCE, vol. 277, no. 5328, 15 August 1997 (1997-08-15), pages 936-938, XP055057541, ISSN: 0036-8075, DOI: 10.1126/science.277.5328.936
5 * PARKES K E B ET AL: “STUDIES TOWARD THE LARGE-SCALE SYNTHESIS OF THE HIV PROTEINASE INHIBITOR RO 31-8959“, JOURNAL OF ORGANIC CHEMISTRY, ACS, US, vol. 59, no. 13/16, 1 January 1994 (1994-01-01), pages 3656-3664, XP002011975, ISSN: 0022-3263, DOI: 10.1021/JO00092A026
6 * R. SANTHOSH REDDY ET AL: “Co(iii)(salen)-catalyzed HKR of two stereocentered alkoxy- and azido epoxides: a concise enantioselective synthesis of (S,S)-reboxetine and (+)-epi-cytoxazone“, CHEMICAL COMMUNICATIONS, vol. 46, no. 27, 1 January 2010 (2010-01-01), page 5012, XP055057537, ISSN: 1359-7345, DOI: 10.1039/c0cc00650e
7 * SHINJI NAGUMO ET AL: “Intramolecular Friedel-Crafts type reaction of vinyloxiranes linked to an ester group“, TETRAHEDRON, vol. 65, no. 47, 1 November 2009 (2009-11-01), pages 9884-9896, XP055057655, ISSN: 0040-4020, DOI: 10.1016/j.tet.2009.09.037
8 * SUNITA K. GADAKH ET AL: “Enantioselective synthesis of HIV protease inhibitor amprenavir via Co-catalyzed HKR of 2-(1-azido-2-phenylethyl)oxirane“, TETRAHEDRON: ASYMMETRY, vol. 23, no. 11-12, 1 June 2012 (2012-06-01), pages 898-903, XP055057475, ISSN: 0957-4166, DOI: 10.1016/j.tetasy.2012.06.003

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Sitasentan TBC 11251


Figure US20120202744A1-20120809-C00005

Sitasentan,TBC 11251

210421-64-0

N-(4-chloro-3-methyl-1,2-oxazol-5-yl)-2-[2-(6-methyl-1,3-benzodioxol-5-yl)acetyl]thiophene-3-sulfonamide

Sitaxentan sodium (TBC-11251) is a medication for the treatment of pulmonary arterial hypertension (PAH).[1] It was marketed as Thelin by Encysive Pharmaceuticals until Pfizer purchased Encysive in February 2008. In 2010, Pfizer voluntarily removed sitaxentan from the market due to concerns about liver toxicity.[2]

Sitaxentan belongs to a class of drugs known as endothelin receptor antagonists (ERAs). Patients with PAH have elevated levels of endothelin, a potent blood vessel constrictor, in their plasma and lung tissue. Sitaxentan blocks the binding of endothelin to its receptors, thereby negating endothelin’s deleterious effects.

Mechanism of action

Sitaxentan is a small molecule that blocks the action of endothelin (ET) on the endothelin-A (ETA) receptor selectively (by a factor of 6000 compared to the ETB).[3] It is a sulfonamide class endothelin receptor antagonist (ERA) and is undergoing Food and Drug Administration (FDA) review for treating pulmonary hypertension. The rationale for benefit compared to bosentan, a nonselective ET blocker, is negligible inhibition of the beneficial effects of ETB stimulation, such as nitric oxide production and clearance of ET from circulation. In clinical trials, the efficacy of sitaxentan has been much the same as bosentan, but the hepatotoxicity of sitaxentan outweighs its benefits. Dosing is once daily, as opposed to twice daily for bosentan.

Regulatory status

On December 10, 2010 Pfizer announced it would be withdrawing sitaxentan worldwide (both from marketing and from all clinical study use), citing that it is a cause of fatal liver damage.[2]

Sitaxentan was approved for marketing in the European Union in 2006, in Canada in 2006[4] and in Australia in 2007. By February 2008 it had been launched commercially in Germany, Austria, The Netherlands, the United Kingdom, Ireland, France, Spain and Italy.

In March 2006, the FDA recommended an approvable status to sitaxentan but said it would not yet approve the product. In July 2006, sitaxentan received a second approvable letter stating that efficacy outcome issues raised in the context of the STRIDE-2 study were still unresolved. In July 2007, Encysive commenced a formal dispute resolution process in a preliminary meeting with the FDA. In September 2007 the company announced that it was making preparations for another phase III clinical trial (intended to be named STRIDE-5) to overcome the FDA’s concerns.[5] The takeover by Pfizer resulted in a reconfiguration and extension of these plans, to include combination therapy with sildenafil. The Sitaxentan Efficacy and Safety Trial With a Randomized Prospective Assessment of Adding Sildenafil (SR-PAAS) was an ongoing program of three clinical trials conducted in the United States (ClinicalTtrials.gov identifiers: NCT00795639, NCT00796666 and NCT00796510) with anticipated completion dates between June 2010 and January 2014.

Sitaxsentan.png

N-(4-Chloro-3-methyl-5-isoxazolyl)-2-[2-(6-methyl-1,3-benzodioxol-5-yl)acetyl]-3-thiophenesulfonamide sodium salt, Sitaxsentan sodium salt, TBC-11251 sodium salt, Thelin

  • CAS Number 210421-74-2
  • Empirical Formula  C18H14ClN2NaO6S2
  • Molecular Weight 476.89

Adverse effects

Adverse effects observed with sitaxentan are class effects of endothelin receptor antagonists, and include :

Because sitaxentan inhibits metabolism of warfarin, a decreased dose of warfarin is needed when co-administered with sitaxentan. This is because warfarin acts to prevent blood from clotting, and if it remains unmetabolized, it can continue to thin the blood.

http://www.google.com/patents/WO2007149568A2?cl=en

As used herein “sitaxsentan” refers to N-(4-chloro-3-methyl-5-isoxazolyl)-2-[2- methyl-4,5-(methylenedioxy)phenylacetyl]-thiophene-3-sulfonamide. Sitaxsentan is also known as TBCl 1251. Other chemical names for sitaxsentan include 4-chloro-3-methyl-5-(2- (2-(6-methylbenzo[d][l ,3]dioxol-5-yl)acetyl)-3-thienylsulfonamido)isoxazole and N-(4- chloro-3-methyl-5-isoxazolyl)-2-[3,4-(methylenedioxy)-6-methylphenylacetyl]-thiophene-3- sulfonamide.

The chemical name for sitaxsentan is N-(4-chloro-3-methyl-5-isoxazolyl)-2-[2- methyl-4,5-(methylenedioxy)phenylacetyl]-thiophene-3-sulfonamide, and its structural formula is as follows:

Sitaxsentan

Sitaxsentan is a potent endothelin receptor antagonist that has oral bioavailability in several species, a long duration of action, and high specificity for ETA receptors.

EXAMPLE 1

Preparation of 4-chloro-3-methyl-5-(2-(2-(6-methylbenzo[d] [l,3|dioxol-5-yl)aeetyl)-3- thienylsulfonamido)isoxazole, or N-(4-chloro-3-methyl-5-isoxazolyl)-2-[2-methy 1-4,5- (methylenedioxy)phenylacetyl]-thiophene-3-sulfonamide, or N-(4-chIoro-3-methyl-5- isoxazolyl)-2-[3,4-(methylenedioxy)-6-methylphenylacetyl]-thiophene-3-sulfonamide.

A. Preparation of (4-chIoro-3-methyl-5-(2-(2-(6-methylbenzo[d] [l,3]dioxol-5-yl)acetyl)- 3-thienylsuIfonamido)isoxazole 1. Preparation of 5-chloromethyI-6-methylbenzo[d][l,3]dioxole

To a mixture of methylene chloride (130 L), concentrated HCl (130 L), and tetrabuylammonium bromide (1.61 Kg) was added 5-methylbenzo[d][l,3]dioxole (10 Kg) followed by the slow addition of formaldehyde (14 L, 37 wt% in water). The mixture was stirred overnight. The organic layer was separated, dried with magnesium sulfate and concentrated to an oil. Hexane (180 L) was added and the mixture heated to boiling. The hot hexane solution was decanted from a heavy oily residue and evaporated to give almost pure 5-chloromethyl-6-methylbenzo[d][l,3]dioxole as a white solid. Recrystallization from hexane (50 L) gave 5-chloromethyl-6-methylbenzo[d][l,3]dioxole (80% recovery after recrystallization). 2. Formation of (4-chloro-3-methyl-5-(2-(2-(2-methyIbenzo[d][l,3]dioxol-5-yl) acetyl)-3-thienylsulfonamido)isoxazole

A portion of a solution of 5-chloromemyl-6-methylbenzo[d][l,3]di-oxole (16.8 g, 0.09 mol) in tetrahydrofuran (THF)(120 mL) was added to a well stirred slurry of magnesium powder, (3.3 g, 0.136 g-atom, Alfa, or Johnson-Mathey, -20 +100 mesh) in THF (120 mL) at room temperature. The resulting reaction admixture was warmed up to about 40-450C for about 2-3 min, causing the reaction to start. Once the heating activated the magnesium, and the reaction began, the mixture was cooled and maintained at a temperature below about 8 0C. The magnesium can be activated with dibromoethane in place of heat.

A flask containing the reaction mixture was cooled and the remaining solution of 5- chloromethlybenzo[d][l,3]dioxole added dropwise during 1.5 hours while maintaining an internal temperature below 8 0C. Temperature control is important: if the Grignard is generated and kept below 8 0C5 Wurtz coupling is suppressed. Longer times at higher temperatures promote the Wurtz coupling pathway. Wurtz coupling can be avoided by using high quality Mg and by keeping the temperature of the Grignard below about 8 0C and stirring vigorously. The reaction works fine at -20 0C, so any temperature below 8 0C is acceptable at which the Grignard will form. The color of the reaction mixture turns greenish.

The reaction mixture was stirred for an additional 5 min at 0 0C, while N2-methoxy- N2-methyl-3-(4-chloro-3-methyl-5-isoazolylsulfamoyl)-2-thiophenecarboxamide (6.6 g, 0.018 mol) in anhydrous THF (90 mL) was charged into the addition funnel. The reaction mixture was degassed two times then the solution of N2-methoxy-N2-methyl-3-(4-chloro-3- methyl-5-isoxazolylsulfamoyl)-2-thiophenecarboxamide was added at 0 0C over 5 min. TLC of the reaction mixture (Silica, 12% MeOHZCH2Cl2) taken immediately after the addition shows no N2-methoxy-N2-methyl-3-(4-chloro-3-methyl-5-isoxazolysulfamoyl)-2-thio- phenecarboxamide. The reaction mixture was transferred into a flask containing IN HCl (400 mL, 0.4 mol

HCl, ice-bath stirred), and the mixture stirred for 2 to 4 min, transferred into a separatory funnel and diluted with ethyl acetate (300 mL). The layers were separated after shaking. The water layer was extracted with additional ethyl acetate (150 mL) and the combined organics washed with half-brine. Following separation, THF was removed by drying the organic layer over sodium sulfate and concentrating under reduced pressure at about 39 0C to obtain the title compound. EXAMPLE 2

1.0 g Sitaxentan was dissolved in 10 ml ethyl acetate and 5 ml hexanes were added. The formed suspension was heated until a clear solution was obtained. Upon cooling light yellow plates were formed. After filtration and drying under vacuum 515 mg of sitaxentan polymorph A was obtained as light yellow plates in very high purity.

EXAMPLE 3

Preparation of 4-chloro-3-methyl-5-(2-(2-(6-methyIbenzo[dJ [l,3]dioxol-5-yl)acetyl)-3- thienylsulfonamido)isoxazole, Sodium Salt

The crystalline sitaxsentan from Example 2 is dissolved in ethyl acetate and washed with saturated NaHCO3 (5 x 10 mL). The solution is washed with brine, dried over Na2SO4 and concentrated in vacuo to obtain a solid residue. 10 mL OfCH2Cl2 is added and the mixture is stirred under nitrogen for 5 to 10 minutes. Ether (15 mL) is added and the mixture stirred for about 10 min. The product is isolated by filtration, washed with a mixture of CH2Cl2 /ether (1 :2) (10 mL) then with ether (10 mL) and dried under reduced pressure to obtain 4-Chloro-3-methyl-5-(2-(2-(6-methyIbenzo[d][l ,3]dioxol-5-yl)acetyl)-3- thienylsulfonamido)isoxazole, sodium salt.

………………………..

 

J. Med. Chem., 1997, 40 (11), pp 1690–1697
DOI: 10.1021/jm9700068
15q.Yellowpowder;
1HNMR(CDCl3):88.88(brs,1H),7.59(s,2H),6.72(s,1H),6.69(s,111),5.94(s,2H),4.22(s,2H),2.22(s,311),2.21(s,3H);
IR(KBrpellet):3455,3233,
3109,2899,1674,1632,1505,1487,1395,1373cm-1;
HRMS:[M+H]*455.0137
………………………..
see
Current Opinion in Investigational Drugs (PharmaPress Ltd.) (2001), 2(4), 531-536.
…………….
Synthesis of Sitaxsentan sodium
Yingyong Huaxue (2007), 24, (11), 1310-1313. Publisher: (Kexue Chubanshe, ) CODEN:YIHUED ISSN:1000-0518.
………………………………………

Table 1: Sitaxsentan Sodium Lyophilized Formulation

References

 1Barst RJ, Langleben D, Frost A et al. (2004). “Sitaxsentan therapy for pulmonary arterial hypertension”. American Journal of Respiratory Critical Care Medicine 169 (4): 441–447. doi:10.1164/rccm.200307-957OC. PMID 14630619.

 

External links

 

US20010021714 * Apr 4, 1996 Sep 13, 2001 Ming Fai Chan Compounds such as n-(4-bromo-3-methyl-5-isoxazolyl)-2-n-benzylbenzo(b)thiophene-3-sufonamide administered as endothelin peptide receptor antagonists
Reference
1 * WU C ET AL: “Discovery of TBC11251, a Potent, Long Acting, Orally Active Endothelin Receptor-A Selective Antagonist” JOURNAL OF MEDICINAL CHEMISTRY, AMERICAN CHEMICAL SOCIETY. WASHINGTON, US, vol. 40, no. 11, 23 May 1997 (1997-05-23), pages 1690-1697, XP002164198 ISSN: 0022-2623
Patent Submitted Granted
ANTIHYPERTENSIVE THERAPY METHOD [US2007293552] 2007-12-20
Crystalline N-(4-chloro-3-methyl-5-isoxazolyl)-2-[2-methyl-4.5-(methylenedioxy)phenylacetyl]-thiophene-3-sulfonamide [US2008026061] 2008-01-31
Gnrh agonist combination drugs [US2005215528] 2005-09-29
THIENYL-, FURYL-, PYRROLYL- AND BIPHENYLSULFONAMIDES AND DERIVATIVES THEREOF THAT MODULATE THE ACTIVITY OF ENDOTHELIN [WO9631492] 1996-10-10
SULFONAMIDES FOR TREATMENT OF ENDOTHELIN-MEDIATED DISORDERS [WO9849162] 1998-11-05
Patent Submitted Granted
Respiratory Drug Condensation Aerosols and Methods of Making and Using Them [US2009258075] 2009-10-15
Method and Composition for Treating Alzheimer’s Disease and Dementias of Vascular Origin [US2010173872] 2010-07-08
Method and Composition for Treating Alzheimer’s Disease and Dementias of Vascular Origin [US2010184725] 2010-07-22
Formulations of sitaxsentan sodium [US2008076812] 2008-03-27
Methods and compositions for treatment of sleep apnea [US2008085313] 2008-04-10
Processes for the preparation of 4-chloro-3-methyl-5-(2-(2-(6-methylbenzo[d][1,3]dioxol-5-yl)acetyl)-3-thienylsulfonamido)isoxazole [US2008086010] 2008-04-10
Method and composition for treating alzheimer’s disease and dementias of vascular origin [US2004092427] 2004-05-13
Method for preventing or treating pulmonary inflammation by administering an endothelin antagonist [US2003004199] 2003-01-02
Methods and Compositions for Treatment of an Interstitial Lung Disease [US2009004268] 2009-01-01
Methods and compositions for treatment of diastolic heart failure [US2007232671] 2007-10-04
Patent Submitted Granted
Isoxazolyl endothelin antagonists [US6043265] 2000-03-28
Aminoguanidine hydrazone derivatives, process for producing the same and drugs thereof [US6350749] 2002-02-26
Method for preventing or treating pain by administering an endothelin antagonist [US6573285] 2002-06-27 2003-06-03
Method for preventing or treating erectile dysfunction by administering an endothelin antagonist [US6268388] 2001-07-31
Method and composition for potentiating the antipyretic action of a nonopioid analgesic [US7351692] 2003-12-25 2008-04-01
Method and Composition for Potentiating an Opiate Analgesic [US8114896] 2010-05-06 2012-02-14
SUBSTITUTED THIOPHENES [US7863308] 2008-10-16 2011-01-04
Respiratory drug condensation aerosols and methods of making and using them [US7550133] 2004-06-03 2009-06-23
SUBSTITUTED THIOPHENES [US2010280086] 2010-11-04
Method and Composition for Potentiating an Opiate Analgesic [US2010311665] 2010-12-09

 

 

 

Sitaxentan
Sitaxsentan.svg
Systematic (IUPAC) name
N-(4-chloro-3-methyl-1,2-oxazol-5-yl)-2-[2-(6-methyl-2H-1,3-benzodioxol-5-yl)acetyl]thiophene-3-sulfonamide
Clinical data
AHFS/Drugs.com International Drug Names
Licence data EMA:Link
Legal status
Routes Oral
Pharmacokinetic data
Bioavailability 70 to 100%
Protein binding >99%
Metabolism Hepatic (CYP2C9– and CYP3A4-mediated)
Half-life 10 hours
Excretion Renal (50 to 60%)
Fecal (40 to 50%)
Identifiers
CAS number 184036-34-8
210421-64-0 (sodium salt)
ATC code C02KX03
PubChem CID 216235
IUPHAR ligand 3950
DrugBank DB06268
ChemSpider 21106381
UNII J9QH779MEM Yes
KEGG D07171
ChEMBL CHEMBL282724
Synonyms Sitaxsentan; TBC-11251
Chemical data
Formula C18H15ClN2O6S2 
Molecular mass 454.906 g/mol

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Antagonists of Endothelin type A receptor ETA
Name Structure
BQ-123 Figure US20120202744A1-20120809-C00001
Bosentan Figure US20120202744A1-20120809-C00002
Atrasentan Figure US20120202744A1-20120809-C00003
Tezosentan Figure US20120202744A1-20120809-C00004
Sitaxsentan Figure US20120202744A1-20120809-C00005
Darusentan Figure US20120202744A1-20120809-C00006
Clazosentan Figure US20120202744A1-20120809-C00007
ZD-4054 (Zibotentan) Figure US20120202744A1-20120809-C00008
Ambrisentan Figure US20120202744A1-20120809-C00009
Tak-044 Figure US20120202744A1-20120809-C00010
Avosentan Figure US20120202744A1-20120809-C00011

 

 

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