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Pramipexole

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Pramipexole, (S)-2-amino-4,5,6,7-tetrahydro-6-(propylamino)benzothiazole, represented by the following formula I (the compound of formula I), is a dopamine D2/D3 agonist used for treatment of Schizophrenia, and particularly for the treatment of Parkinson’s disease.

Pramipexole is marketed in the form of dihydrochloride monohydrate salt under the brand name Mirapex.

Pramipexole (Mirapex, Mirapexin, Sifrol) is a dopamine agonist of the non-ergoline class indicated for treating Parkinson’s disease(PD)^[1] and restless legs syndrome (RLS).^[2]

Formula I

Indian patent application no. 605/MUM/2008 describes a process for the preparation of the dihydrochloride salt of the compound of formula I.

Synthesis

Pramipexole can be synthesized from a cyclohexanone derivative by the following route:

Pramipexole synthesis:^[14]

Research

Pramipexole has been evaluated for the treatment of cluster headache and to counteract problems with sexual dysfunction experienced by some users of selective serotonin reuptake inhibitor (SSRI) antidepressants.^[15] Pramipexole has shown effects on pilot studies in a placebo-controlled proof of concept study in bipolar disorder.^[8]^[16]^[17] It is also being investigated for the treatment of clinical depression and fibromyalgia.^[18]^[19]^[20]

Paper

Org. Process Res. Dev., 2010, 14 (5), pp 1125–1129

DOI: 10.1021/op1000989

http://pubs.acs.org/doi/abs/10.1021/op1000989

Pramipexole is a dopamine D₂ subfamily receptor agonist that is used for the treatment of Parkinson’s disease. We report here on the successful application of the Fukuyama alkylation protocol to the development of a novel and scalable process for synthesis of pramipexole and its pharmaceutically acceptable salts. The synthesis consists of converting the crucial intermediate (S)-2,6-diamino-4,5,6,7-tetrahydrobenzothiazole to (6S)-N-(2-amino-4,5,6,7-tetrahydrobenzothiazole-6-yl)-2-nitrobenzenesulfonamide, which is in turn monoalkylated to (6S)-N-(2-amino-4,5,6,7-tetrahydrobenzothiazole-6-yl)-2-nitro-N-propylbenzenesulfonamide. Deprotection of the latter yields pramipexole base, which is finally converted to a crude pramipexole dihydrochloride monohydrate with a yield of over 50% over four steps. The process allows for the telescoping of the final three steps, has high conversion rates of intermediates, offers ease of purification, and preserves high optical purity throughout all of the stages.

pramipexole dihydrochloride monohydrate 13 (315 g) with a yield of 70% (calculated from 12) and an HPLC purity of 94.4%. ¹H NMR (300 MHz, DMSO-d₆) δ 0.89 (t, J = 7.5 Hz, 3H), 1.62−1.75 (m, J = 7.6 Hz, 2H), 1.87−2.00 (m, 1H), 2.24−2.28 (m, 1H), 2.55−2.67 (m, 2H), 2.71−2.79 (m, 1H), 2.86−2.89 (m, 2H), 2.99−3.06 (m, 1H), 3.47 (m, 1H), 9.50 (m, 2H). ¹³C NMR (300 MHz, DMSO-d₆) 11.1, 19.1, 20.9, 23.5, 24.8, 46.0, 52.3, 111.0, 132.9, 168.7. FT-IR (cm⁻¹): 3150−3450 (NH₂ stretching), 2700−3000 (C−H stretching), 1600−1650 (C═N stretching), 1550−1600 (heteroaromatic ring skeleton).

POSTER

A NEW, EFFICIENT AND ECONOMIC METHOD FOR PREPARATION OF PRAMIPEXOLE.

Roman Balicki , Agnieszka Ciesielska , Michał Odrowąż-Sypniewski

Pharmaceutical Research Institute (IF), Rydygiera 8, Warszawa 01-793, Poland

Abstract

Pramipexole is a novel nonergot dopamine agonist which has high selectivity for interacting with dopamine D₂ receptors. It is effective in early Parkinson,s disease as monotherapy and as adjunctive therapy with L-dopa in advanced stages of the disease.

Known, two-steps method for preparation of pramipexole (3) is based on acylation reaction of diamine 1 with propionic anhydride. The obtained amide 2 is subsequently reduced using borane to give final product 3 with 65% yield.

Now, we present novel, more economic and safe procedure for obtaining pramipexole. Our one-step method requires only alkylation of 1 using n-propyl tosylate. Dangerous reduction with borane is eliminated and the final compound is obtained with similar yield as in a previous method.

Patent

http://www.google.com/patents/US7741490

Pramipexole, of formula (A)

is a dopaminergic agonist, known from U.S. Pat. No. 4,843,086, used in the treatment of Parkinson’s disease in the form of dihydrochloride monohydrate.

US 2002/0103240 discloses inter alia a method for the resolution or the enrichment of (R,S)-2-amino-6-propylamino-4,5,6,7-tetrahydrobenzothiazole in the single (R) or (S) enantiomers, in particular in the (S) enantiomer. The same application illustrates in detail the synthetic routes known for the preparation of pramipexole, in particular those described in U.S. Pat. No. 4,886,812, EP 186087, EP 207696 and J. Med. Chem. 30. 494 (1987). From what reported it is evident that the synthetic pathways up to now available make use of synthetic steps that do not fulfill the requirements for the production of pramipexole on the industrial scale. Therefore there is the need for an improved process, which is simpler, easier to carry out and meets the requirements for the industrial production of pramipexole.

Example 13 Intermediate (VIII) Ra=H; Pramipexole Free Base

A 2 liter reactor under nitrogen is loaded with 53.3 g of, 33.0 g of (S) N-(6-propionylamino-4,5,6,7-tetrahydro-benzothiazol-2-yl)-amine, 95% sodium borohydride and 260 ml of tetrahydrofuran (THF). A solution of 98.7 g of iodine in 160 ml of THF is dropped therein in about 3 hours, keeping the temperature at approx. 20-25° C. The reaction mixture is kept under stirring for further 2 hours at about 20-25° C. The reaction mixture is poured into a solution of 60.0 g of 37% HCl in 260 ml of water. The mixture is heated to 50-55° C. and left under stirring for an hour. The complete cleavage of the boran-complexes is checked by HPLC. The mixture is added with 250 g of 50% aqueous NaOH, keeping the temperature at about 20-25° C. After that, 315 ml of toluene are added and the mixture is heated to about 30-35° C. Stirring is interrupted and the two phases are separated. The organic phase are washed, concentrated to a residue and dissolved in 420 ml of ethyl acetate.

The solution is concentrated under vacuum at a temperature below 50° C. to about 150 ml volume. The resulting suspension is refluxed, then cooled to about 10-15° C., stirred for further 1-2 hours, then filtered with suction and the precipitate is washed twice with 30 ml of ethyl acetate. The product is dried under vacuum at 40° C. 32 g of (S)-2-amino-6-propylamino-4,5,6,7-tetrahydrobenzothiazole are obtained.

PATENT

https://www.google.sc/patents/WO2008097203A1?cl=en

Example 1

Synthesis of N-(2-amino-4,5, 6, 7-tetrahydrobenzo[d]thiazole-6-yl)-2- n itrobenzenesulfonam ide

o-Nitrobenzenesulfonyl chloride (8.865 g, 40 mmol) was dissolved in 100 ml of THF and during stirring cooled to -10⁰C (ice + salt). Then, first 3 equiv. of triethylamine (Et₃N) (120 mmol, 16.8 ml) and then also 1.1 equiv. of 4,5,6,7-tetrahydrobenzo[J]thiazol-2,6-diamine (7.605 g, 45 mmol) were added. The formed suspension was, during stirring, gradually heated to room temperature and was left standing until the reaction was completed. In the course of the reaction, in addition to a soluble product, also in THF non-soluble Et₃NH⁺Cl^“ was formed, which was, at the end of the reaction, filtered off by suction and the reaction mixture was evaporated to dryness on a rotatory evaporator. The residue was poured over with H₂O (300 ml), whereby on the bottom of a round-bottom flask an orange viscous liquid was obtained. After rubbing with the glass stick a yellow precipitate (N-(2- amino-4,5,6,7-tetrahydrobenzo[^thiazole-6-yl)-2-nitrobenzenesulfonamide) was formed. The precipitate was filtered off and washed with 100 ml of cold ethylether and dried. The yield of the reaction was 95%.

Example 2

Synthesis of N-(2-amino-4,5,6, 7-tetrahydrobenzo[d]thiazole-6-yl)-2-nitro-N- propylbenzenesulfonamide

Process A:

N-(2-amino-4,5,6,7-tetrahydrobenzo[rf]thiazole-6-yl)-2-nitrobenzenesulfonamide (1.770 g, 5 mmol) and K₂CO₃ (2.856 g, 20 mmol) were suspended in acetonitrile (40 ml) and was, during stirring, heated to 60⁰C. Then propylbromide (1.65 ml, 18 mmol) was added and the reaction was left to run over night (the course of the reaction was followed by the use of a suitable method).

After the reaction was completed, the present precipitate was filtered off by suction. The reaction mixture was evaporated to dryness and the residue was dissolved in dichloromethane (150 ml). Organic phase was washed with IM NaOH (3 x 50 ml), saturated NaCl solution (2 x 50 ml) and dried with Na₂SO₄. After evaporation of dichloromethane an orange oily product N-(2-amino-4, 5,6,7- tetrahydrobenzo[^thiazole-6-yl)-2-nitro-Ν-propylbenzenesulfonamide was obtained.

Process B:

N-(2-amino-4,5,6,7-tetrahydrobenzo[rf]thiazole-6-yl)-2-nitrobenzenesulfonamide (1.770 g, 5 mmol), Cs₂CO₃ (3.909 g, 12 mmol) and KI (0.415 g, 2.5 mmol) was suspended in acetonitrile (40 ml) and heated to 60⁰C. Then propyl bromide (0.9 ml, 10 mmol) was added and the course of the reaction was followed by the use of a suitable method.

The process of the isolation was the same as in the process A.

Example 3

Synthesis of lf-propyl-4,5,6, 7-tetrahydrobenzo[d]thiazole-2,6-diamine

Process A:

K₂CO₃ (2.073 g, 15 mmol) was suspended in 20 ml of DMF (stored above molecular sieves), thioglycolic acid (SHCH₂COOH, 0.6 ml, 7.5 mmol) was added and stirred for 30 minutes. Then N-(2-amino-4,5,6,7-tetrahydrobenzo[d]thiazole-6-yl)-2-nitro-N- propylbenzenesulfonamide ( 0,99 g, 2,5 mmol), dissolved in 20 ml of DMF was added and the reaction was left to run over night. After the reaction was completed, DMF was evaporated, the residue was poured over with H₂O (100 ml) and IM NaOH (200 ml). The aqueous phase was then washed with dichloromethane (3 x 80 ml) and the combined organic fractions were dried with z Na₂SO₄. After the evaporation of the solvent an oily residue of orange-red colour (presence of DMF is possible) was obtained.

Process B:

LiOH (0.5 g, 20 mmol) was suspended in 20 ml of DMF (stored above molecular sieves), thioglycolic acid (SHCH₂COOH, 0.6 ml, 7.5 mmol) was added and stirred for 30 minutes. Then N-(2-amino-4,5,6,7-tetrahidrobenzo[cT|thiazole-6-yl)-2-nitro-N- propylbenzenesulfonamide (0.99 g, 2.5 mmol), dissolved in 20 ml of DMF was added and the reaction was left to run over night (the solution was coloured in orange-red).

After the reaction was completed, DMF was evaporated off, the residue was poured over with H₂O (100 ml) and IM NaOH (200 ml). The aqueous phase was then washed with dichloromethane (3 x 80 ml) and the combined organic fractions were dried with Na₂SO₄. After the evaporation of the solvent an oily residue of an orange- red colour was obtained.

Example 4

Pramipexole dihydrochloride monohydrate

(S)-(-)-2-Amino-6-(N-propylamino)-4,5,6,7-tetrahydrobenzothiazole (9.15 g, 43.28 mmol) in 500 ml round-bottom flask was dissolved in 30 ml of ethanol and water (0.78 g, 43.33 mmol) was added. A solution was cooled in an ice bath to 0⁰C and gaseous HCl^₎₁ was blown through whereby a white precipitate fell out. The round- bottomed flask was sealed and it was stirred over night at room temperature. The next day the precipitate was filtered off by suction and washed with a small amount of anhydrous ethanol. The precipitate was transferred into 100 ml round-bottom flask and anhydrous ethanol (50 ml) was added. The suspension was heated to 45°C and ethanol was evaporated on a rotatory evaporator. The process was repeated for another two times in order to drive out all of the excessive HCl_(g). The product was recrystallized from methanol: a salt was dissolved in methanol (70 ml) at 45⁰C, approximately 40 ml of methanol was evaporated and 20 ml of ethanol were added. It was cooled to room temperature and the resulting precipitate was filtered by suction, washed with some cooled anhydrous ethanol and dried in vacuum over P₂O₅ and NaOH. Yield: 11.631 g (89.01 %)

Example •§

Synthesis of N-(2-amino-4, 5, 6, 7-tetrahydrobenzo[d]thiazole-6-yl)-2- nitrobenzenesulfonamide

2-Nitrobenzenesulfonyl chloride (390 g, 1.76 mol) was dissolved in 4 1 of THF. The solution was cooled to approximately -10⁰C. Triethylamine (Et₃N) (740 g, 7.313 mol) and (6S)-4,5,6,7-tetrahydrobenzotiazole-2,6-diamine (327 g, 1.932 mol) were added. The suspension was heated during mixing to approximately 25°C and allowed to react at this temperature for approximately 1 hour.

Precipitated triethylammonium chloride (Et₃NH⁺Cl^“) was filtered off. The filtrate was concentrated to about 1/3 of the volume and water (2 1) was added. Again, approximately 1/2 of the solvent was distilled off. Water (2 1) was added, the mixture was cooled to about 25°C and mixed for about 1 hour. The precipitated product ((6S)- N-(2-amino-4,5,6,7-tetrahydrobenzotiazole-6-yl)-2-nitrobenzenesulfonamide) was separated by filtration or centrifuging.

Example g

Synthesis of (S)-(-)-2-Amino-6-(N-propylamino)-4,5,6, 7-tetrahidrobenzo[d]thiazole dihydrochloride hydrate

Potassium carbonate (1890 g, 13.675 mol), (6S)-N-(2-amino-4,5,6,7- tetrahydrobenzotiazole-6-yl)-2-nitrobenzenesulfonamide (590 g, 1.665 mol) and propyl bromide (1.09 1, 12 mol) were suspended in 4.1 1 of acetonitrile. The mixture was heated during stirring to approximately 60⁰C and mixed at this temperature for about 12 hours. The mixture was cooled to about 25°C. Potassium bromide was removed by filtration. The solution was concentrated to about 1/4 of the volume (not exceeding 60⁰C) and cooled to the room temperature. Methylene chloride (2 1) and 1 M NaOH water solution (2.43 1) were added and the mixture was mixed for about 30 minutes. Phases were separated and water phase was washed again with methylene chloride (1.46 1). Organic phases were collected and concentrated to about 1/10 of the volume. 0.83 1 of ethanol was added and the solution was concentrated to 1/10 of the volume. 3.35 1 of ethanol was added and ethanolic solution of (6S)-N-(2-amino- 4,5 ,6,7-tetrahydrobenzotiazole-6-yl)-2-nitro-Ν-propylbenzenesulfonamide was stored for further reaction.

Ethanol (2.35 1) and of LiOH (288 g, 12 mol) were put into the reactor and the suspension was cooled to 0 – 5°C. During about 30 minutes thioglycolic acid (SHCH₂COOH) (720 g, 7.816 mol) was added (the temperature must not exceed 25°C). The suspension was heated to about 25°C and mixed for about 45 minutes. Ethanolic solution of (6S)-N-(2-amino-4,5,6,7-tetrahydrobenzotiazole-6-yl)-2-nitro-N- propylbenzenesulfonamide was added. The air in the reactor was replaced by nitrogen. The mixture was heated to about 50⁰C and mixed at this temperature for about 4 hours. The mixture was cooled to about 25°C and filtrated. The filtrate was concentrated at 40⁰C to about 1/4 of the volume and cooled to the ambient temperature. Methylene chloride (4.23 1) and of IM aqueous NaOH solution solution (2.53 1) were added and the mixture was mixed for about 30 minutes. Phases were separated and water phase was washed again with 4.23 1 of methylene chloride. Organic phases containing pramipexole were collected and concentrated to about 1/4 of the volume. 5 1 of ethanol was added.

To the ethanolic solution of pramipexole water was added (27.6 ml, 1.53 mol) and solution was cooled to about -10⁰C. Gaseous HCl_(g) was introduced into the solution (200 g). The temperature of the solution and later the suspension must not exceed 25⁰C during addition of gaseous HCl_(g) . After the addition the suspension was heated to about 4O⁰C and concentrated to 2/3 of the volume. 2.65 1 of ethanol was added and the suspension was concentrated to 1/2 of the volume. Again 3.5 1 of ethanol was added and the suspension was concentrated to 1/2 of the volume. The solution was cooled to about -15°C and the product was separated by filtration. The product was dried at 25°C and finally at 40⁰C on air.

PATENT

http://www.google.com/patents/WO2008041240A1?cl=en

(S)-2-amino-6-propylaminio-4,5,6,7- tetrahydrobenzothiazole of formula (I), which is more commonly known as Pramipexole. Pramipexole is the commercial product marketed, in a form of a dihydrochloride salt in a peroral formulation, under several brand names e.g. Mirapexin[TM].

The compound of formula (I) has one symmetric carbon and they may exist either as a single enantiomer or in a mixed or racemic form. The pharmacological activity of compounds of formula (I) is generally connected only or mainly with one isomer thereof. Accordingly, the dopaminergic activity of the (S) isomer is twice as high as that of the (R) enantiomer.

A general process for the preparation of Pramipexole dihydrochloride has been described in US 4886812, EP 186087 and EP 207696. The process comprises the protection of amino function of 4-aminocyclohexanol to give the intermediate compound wherein, Rl is acyl or alkoxycarbonyl and R2 is hydrogen or Rl and R2 together form an amino protective group such as pthalimido group which on oxidation with an oxidising agent, followed by halogenation (preferably bromination) of protected ketone to give alpha halogenatedketone which on reaction with thiourea, followed by deprotection yielded the racemic 2,6-diaminotetrahydrobenzothiazole. Reductive alkylation of diaminotetrahydrobenzothiazole with n-propanal furnished the racemic pramipexole. Although the (S) isomer of pramipexole is mentioned therein, it is not clear at what stage the chiral resolution has been carried out. The general process steps are indicated in Scheme- Ia below.

H₂N

Racemate Resolution

n-Propyl Bromide –

Scheme-la

Another process for preparing optically pure pramipexole dihydrochloride was disclosed in J. Med. Chem. 1987, 30, 494-498, wherein, racemic 2,6-diamino-4,5,6,7- tetrahydrobenzo- thiazole was resolved, using L (+) tartaric acid to give optically pure (S)-2,6-diamino-4,5,6,7-tetrahydrobenzothiazole, which was converted to optically pure pramipexole by reacting (S)- 2,6-diamino-4,5,6,7-tetrahydro benzothiazole with propionic anhydride in THF and followed by reduction with borane THF complex . The reaction steps are shown in Scheme-lb as under:

(VIII) (II)

(CH3CH2CO)₂O

2HCl Scheme- Ib

However, the variants of the above general process prepare only racemate.

Thus, the synthesis of pramipexole by the above process yields R,S(±)-2~amino-6- propylamino-4,5,6,7-tetrahydrobenzothiazole. The above-mentioned acknowledge that the produced racemic compound may be resolved into single enantiomers by classical methods such as chromatography on a chiral phase or fractional crystallization of a salt with an optically active acid. However, even though the S(-)-enantiomer of pramipexole was disclosed and characterized therein, no information is provided how it was prepared; i.e. whether it was prepared by a resolution of racemic pramipexole of form some optically active precursor. Further, no information is provided on how to produce the S(-)- enantiomer of pramipexole.

WO 2006/003677 Al discloses the improved process the preparation of biologically active tetrahydrobenzothiazole derivative. The patent application discloses the process that has tried to solve the problems of prior art. However, much improvement over the prior art process has still been achieved. Moreover, the process discloses the formation of 2,6-diamino-4,5,6,7-tetrahydrobenzothiazole via an isolated bromo intermediate, which on reaction with thiourea gets converted to tetrahydrobenzothiazole. The isolation of bromo intermediate can also be avoided. The halogenation of the protected cyclohexanone derivative is performed in presence of Lewis acid catalysts like AICI₃, ZnCl₂ or SnCl₂ etc. which will give aluminous waste though increase the yield during the halognation reaction. Moreover, the overall steps of the reaction will increase by performing isolation and work up for bromo intermediate.

US 6,727,637 B2 discloses the monobasic acid addition salts and the mixed salts of 2-amino-6-propylamino-4,5,6,7-tetrahydrobenzothiazole wherein the monobasic acid includes hydrochloric, hydrobromic, hydroiodic, nitric, benzoic, acetic, methane sulfonic, ethane sulfonic, trifluromethane sulfonic, benzene sulfonic, and p- toluene sulfonic acids. Further the patent US ‘637 B2 discloses the formation of mixed salts like of 2-amino-6-propylamino-4,5,6,7-tetrahydrobenzothiazole monohydrochloride monotartrate, of 2-amino-6-propylamino -4,5,6,7- tetrahydrobenzothiazole monohydrobromide monotartrate or of 2-amino-6- propylamino-4,5,6,7-tetrahydrobenzothiazole. monomethane sulfonate dibenzoyl-D- tartrate. The process as disclosed in US ‘637 B2 converts the racemic pramipexole into monohydrochloride salt of pramipexole which is then resolved with a optically active auxilliary acid to give mixed salt like of 2-amino-6-propylamino-4,5,6,7-tetrahydro- benzothiazole monohydrochloride monotartrate which is then converted to (S)- pramipexole free base and then to the desired pharmaceutically active ingredient (S)- pramipexole dihydrochloride.

US 6,770,761 B2 also discloses the process for preparation of 2-amino-6(alkyl)- amino-4,5,6,7-tetrahydrobenzothiazoles which includes the bromination of 1,4- cyclohexadione by bromine in an alcoholic solvent, followed by treatment of the reaction mixture with thiourea or N-acylthiourea and isolation of compound (A), that is further treated with an amine R₁-NH₂ or a chiral amine to get an imine intermediate and reducing it by reaction with said reducing agent or by hydrogenation, to yield the compound of formula (B)

(A) (B) Polymorphism is the occurrence of different crystalline forms of a single compound and it is a property of some compounds and complexes. Thus, polymorphs are distinct solids sharing the same molecular formula, yet each polymorph may have distinct physical properties. Therefore, a single compound may give rise to a variety of polymorphic forms where each form has different and distinct physical properties, such as different solubility profiles, different melting point temperatures and/or different x- ray diffraction peaks. Since the solubility of each polymorph may vary, identifying the existence of pharmaceutical polymorphs is essential for providing pharmaceuticals with predicable solubility profiles. It is desirable to investigate all solid-state forms of a drug, including all polymorphic forms, and to determine the stability^ dissolution and flow properties of each polymorphic form. Polymorphic forms of a compound can be distinguished in a laboratory by X-ray diffraction spectroscopy and by other methods such as, infrared spectrometry. For a general review of polymorphs and the pharmaceutical applications of polymorphs see G. M. Wall, Pharm Manuf. 3, 33 (1986); J. K. Haleblian and W. McCrone, J. Pharm. ScL, 58, 911 (1969); and J. K. Haleblian, J. Pharm. ScL, 64, 1269 (1975), all of which are incorporated herein by reference.

Example-1: Preparation of 2-amino-6-phthaIimido-4,5,6,7- tetrahydrobenzothiazole A) Preparation of chromic acid:

0.278 kg of chromium trioxide was added in 0.428 L of water at 15⁰C to 35°C. The reaction mixture was cooled to 5⁰C to 1O⁰C. 0.198 L of sulfuric acid Was added slowly within 25 to 30 minutes. 1.0 L of water was added to get the clear solution. B) Preparation of 2-amino-6-phthalimido-4,5,6,7-tetrahydrobenzothiazole via 4- (phthalimido)-cyclohexanone

1.0 Kg of 4-(phthalimido)-cyclohexanol was added in 20.0 L of acetone at 25⁰C to 35⁰C. The reaction mixture was cooled to 5⁰C to 10⁰C and treated with chromic acid solution. 0.2 L of isopropanol was added and stirred for 30 min. The reaction mixture was filtered and washed with acetone (1.0 L). The filtrate was treated with 0.4 kg sodium bicarbonate at 25⁰C to 35⁰C and stirred for 1 h. The reaction mass was again filtered, washed with acetone (1.0 L). Excess of acetone was distilled under vacuum. The residue was treated with 0.5 L ethanol followed by distillation of ethanol under vacuum. The reaction mass was cooled and treated with 3.36 L ethanol at 45⁰C to 25⁰C while gradual cooling. The reaction mixture was further cooled to 15⁰C to 2O⁰C and treated with 0.22 L of bromine and 0.43 Kg of thiourea under stirring for 1 h. The reaction mixture was heated to reflux at 75⁰C to 78⁰C for 6 hrs. The reaction mixture was cooled and stirred for 1 hr at 5⁰C to 1O⁰C. The product was isolated by centrifuge, washing with ethanol 0.66 L and drying under vacuum at 5O⁰C t0 55⁰C. (yield: 0.70 Kg).

ExampIe-2: Preparation of 2, 6-diamino-4,5,6,7-tetrahydrobenzothiazole

1.595 kg of 2-amino-6-phthalimido-4,5,6,7-tetrahydrobenzothiazole was treated with 40% aqueous solution of monomethylamine at 25⁰C to 35⁰C. The reaction mass was allowed to stir for 5-10 minutes and heated at 45°C to 5O⁰C for 1 – 1.5 hr. The reaction mixture was cooled gradually to 5⁰C to 1O⁰C and maintained for 30 minutes. The product thus obtained was filtered, washed with chilled water and dried at 5O⁰C to 55⁰C to obtained racemic 2,6-diamino-4,5,6,7-tetrahydrobenzothiazole. (Yield: 0.522 kg)

Example-3: Preparation of 2, 6-diamino-4,5,6,7-tetrahydrobenzothiazoIe tartrate salt

1.0 Kg of 2, 6-diamino-4,5,6,7-tetrahydrobenzothiazole was added in 9.5 L of water and heated at 75⁰C to 85⁰C. 0.888 Kg of L-(+)-tartaric acid was added to the reaction mixture and maintained for 30 minutes. The reaction mixture was fine filtered at high temperature and washed with 0.5 L of water. The filtrate was gradually cooled to 25⁰C to 30⁰C and maintained for 16 hours. The product was centrifuge and washed with 1 L water. The wet cake was treated with 6.0 L water and heated at 😯⁰C to 9O⁰C with addition of excess water to ensure clear solution. The reaction mass was fine filtered at high temperature and washed with 0.5 L water. The filtrate thus obtained was gradually cooled to 5°C to 1O⁰C and maintained for 2 hrs. The product was centrifuge and washed with 1 L chilled water. The wet cake was treated with 6.0 L water and heated at 😯⁰C to 9O⁰C with addition of excess water to ensure clear solution. The reaction mass was gradually cooled to 95⁰C to 25°C and maintained for 2 hrs. The product was centrifuge, washed with 1 L chilled water, dried at 5O⁰C to 55⁰C and cooled to 25⁰C to 35⁰C. (Yield: 0.70 Kg). ExampIe-4: Preparation of (S)-2,6-diamino-4,5,6,7-tetrahydrobenzothiazole

1.0 Kg of 2, 6-diamino-4,5,6,7-tetrahydrobenzothiazole tartrate salt was treated with 1.5 L of water and stirred for 15 minutes at 25°C to 35°C. 0.245 Kg of sodium hydroxide solution in 0.612 L of water was added to adjust the pH 11.0 to 12.0 within 35 to 40 minutes and stirred for 1 hr. The product was centrifuge, washed with 1.0 L water and dried at 50⁰C to 55⁰C. The product was cooled to 20°C-40°C to obtain (S)- 2,6-diamino-4,5,6,7-tetrahydrobenzothiazole. (Yield: 0.37 Kg). Example-5: Preparation of Pramipexole crude

To the solution of 1.0 Kg of (S)-2,6-diamino-4,5,6,7-tetrahydrobenzothiazole and 0.1225 Kg of potassium carbonate in 10.0 L isopropanol was added 0.540 L n- propyl bromide. The reaction mixture was stirred for 15 minutes and heated to reflux on a water bath up to 😯⁰C and was maintained for 5 hours. 0.3236 L of n-propyl bromide was further added in two portions at 😯⁰C to 82°C and maintained for 5 hours. The isopropanol was removed completely by distillation under vacuum at 55⁰C to 75⁰C. 7.5 L of process water was added into the reaction mass and stirred for 30 minutes. The reaction mixture was cooled to 25⁰C to 35⁰C. 40% sodium hydroxide solution (0.108 Kg in 0.27 L water) was added to adjust the constant pH 10.0 to 10.5 followed by treatment with 5.0 L methylene dichloride twice and separating the organic layer. The organic layer was treated with 5.0 L of process water and stirred for 30 minutes. The separated organic layer was subjected to distillation to remove methylene dichloride under vacuum. 5.0 L of isopropanol was added at 4O⁰C to 45⁰C and heated up to 6O⁰C to 65⁰C. Acidic isopropanol 0.440L was added to adjust the pH 7.0 to 7.5 and stirred for 1 hour. The reaction mass was cooled to 25⁰C to 35°C. The product was obtained by centrifuge, washing with 0.5 L of isopropanol and drying at 5O⁰C to 55⁰C followed by cooling. (Yield: 1.0 Kg)

ExampIe-6: Preparation of Pramipexole dihydrochloride monohydrate

1.0 Kg of crude Pramipexole was added in 5.0 L of ethanol and heated to reflux using water bath at 80⁰C. The reaction mixture was maintained for 1 hour and cooled to 25⁰C to 35°C and stirred for 1 hour. The product was centrifuge and washed with 0.5 L ethanol. The wet cake thus obtained was further treated with 5.0 L of ethanol and heated to reflux using water bath at 😯⁰C. The reaction mixture was maintained for 1 hour and cooled to 25⁰C to 35⁰C and stirred for 1 hour. The product was centrifuge and washed with 0.5 L ethanol. The wet cake was treated with 5.0 L isopropanol and heated to 6O⁰C to 65°C using water bath. Acidic isopropanol 0.35 L was added to adjust the pH 1.7 to 2.3 and maintained for 1 hour. The product was centrifuge and washed with 1 L of isopropanol and dried in hot air oven at 5O⁰C to 55⁰C to give Pramipexole dihydrochloride pure, which is converted to Pramipexole dihydrochloride monohydrate upon cooling the dried material under airflow. (Purity: 99.5% by HPLC and having known individual impurities less than 0.1% and total impurities less than 1.0%.) Example-7.: Preparation of Pramipexole dihydrochloride monohydrate

1.0 Kg of crude Pramipexole was added in 5.0 L of ethanol and heated to reflux using water bath at 😯⁰C. The reaction mixture was maintained for 1 hour and cooled to 25⁰C to 35⁰C and stirred for 1 hour. The product was centrifuge and washed with 0.5 L ethanol. The wet cake thus obtained was further treated with 5.0 L of ethanol and heated to reflux using water bath at 80⁰C. The reaction mixture was maintained for 1 hour and cooled to 25⁰C to 35⁰C and stirred for 1 hour. The product was centrifuge and washed with 0.5 L ethanol. The wet cake was treated with 5.0 L isopropanol and heated to 60⁰C to 65⁰C using water bath. Isopropanolic HCl (0.35 L) containing water was added to adjust the pH 1.7 to 2.3 and maintained for 1 hour. The product was centrifuge and washed with 1 L of isopropanol and dried at 4O⁰C to 5O⁰C to give Pramipexole dihydrochloride monohydrate

PATENT

New patent, WO 2015155704, An improved process for the preparation of pramipexole dihydrochloride monohydrate

WO 2015155704, An improved process for the preparation of pramipexole dihydrochloride monohydrate

PIRAMAL ENTERPRISES LIMITED [IN/IN]; Piramal Tower, Ganpatrao Kadam Marg Lower Parel Mumbai 400013 (IN)

Inventors:

PATIL, Pravin; (IN).
PANSARE, Prakash; (IN).
JAGTAP, Ashutosh; (IN).
KRISHNAMURTHY, Dhileepkumar; (IN)

Formula I

The compound of formula I is disclosed in US Patent no. 4,886,812 (US ‘812 Patent). The US’ 812 Patent also describes a process for the preparation of the compound of formula I and its dihydrochloride monohydrate salt involving the propylation reaction of the compound of formula II with n-propylbromide as a propylating agent in the presence of potassium carbonate by using methanol as a solvent to provide the reaction mixture. The resulting reaction mixture is then refluxed for 3 hours. After completion of the reaction, water is added to the reaction mixture. The reaction mixture is then extracted with ethyl acetate and concentrated to obtain the residue. The obtained residue is purified by silica gel chromatography and the corresponding fraction is concentrated under reduced pressure to obtain the compound of formula I which is then converted into its dihydrochloride monohydrate salt. Although, US ‘812 Patent describes the process for the preparation of the compound of formula I from the compound of formula II, it does not teach the process for converting the compound of formula I into its dihydrochloride monohydrate salt. Also, the process described in US ‘812 Patent involves propylation of the compound of formula II using 4 molar equivalents of n-propylbromide as the propylating agent. N-propylbromide is known to be carcinogenic compound and its average threshold limit value for 8 hours exposure is 10 parts per million. Therefore, on commercial scale, excess use of such a hazardous reagent is not desirable. Further, propylation of the compound of formula II using the process described in US ‘812 Patent generates one major impurity namely (6S)-2,6-benzothiazolediamine,4,5,6,7-tetrahydro-N²,N⁶-dipropyl. The US ‘812 Patent does not teach any purification method for removal of this impurity.

Indian Patent Application no. 694/MUM/2006 describes a process for the preparation of the dihydrochloride monohydrate salt of the compound of formula I involving treating the alcoholic solution of the compound of formula I with hydrochloric acid and precipitating the dihydrochloride monohydrate salt of the compound of formula I by addition of water. The process disclosed in this patent application does not involve any purification step for the purification of the compound of formula I or its dihydrochloride monohydrate salt and thus, the final active pharmaceutical ingredient (API), the dihydrochloride monohydrate salt of the compound of formula I prepared by this process does not have the desired pharmaceutically acceptable purity.

Indian patent application no. 605/MUM/2008 describes a process for the preparation of the dihydrochloride salt of the compound of formula I. The process for the preparation of the dihydrochloride salt of the compound of formula I involves the propylation reaction of the compound of formula II with n-propanal as a propylating agent by using a mixture of methanol and water as the solvent. To the resulting reaction mixture, glacial acetic acid and sodium borohydride are charged and the reaction mixture is stirred for 30-40 minutes at a temperature of 15 to 20°C. The reaction mixture is then cooled to -5 to 0°C and to the reaction mixture; second lot of n-propanal with methanol and sodium borohydride is added. The resulting reaction mixture is stirred for 30-40 minutes and quenched with brine solution. The reaction mixture is distilled under vacuum to obtain a residue. To the obtained residue, ethyl acetate and water are added. Two layers formed are separated and ethyl acetate layer is concentrated under vacuum to obtain the crude compound of formula I. The resulting crude compound of formula I is then recrystallised by using acetonitrile to yield the pure compound of formula I. To the pure compound of formula I; ethanolic hydrochloric acid solution is added. The reaction mixture is stirred for 1 hour to precipitate the solid. The precipitated solid is filtered and suspended in ethanol. The reaction mixture is then stirred at reflux temperature for 30 minutes and at room temperature for 1 hour to precipitate the dihydrochloride salt of the compound of formula I. The precipitated dihydrochloride salt of the compound of formula I is dissolved in a mixture of ethanol and water; and filtered through hyflo. The filtrate is then distilled under vacuum and recrystallised by using ethanol to obtain the pure dihydrochloride salt of the compound of formula I. The process disclosed in said patent involves the use of 3 molar equivalents of sodium borohydride and n-propanal which renders the process costlier and hence, this process is not viable for scale up.

The general process for producing the dihydrochloride monohydrate salt of the compound of formula I is depicted in the following Scheme I:

(S)-2-amino-6-propinamido-4, 5,6,7- tetrahydrobenzothiazole

sodium borohydride

o e compoun o ormu a

Scheme I

Scheme-II.

methanol-water purification

Scheme-II

Examples

Example 1:

Step A: Synthesis of compound of formula I:

To the reaction flask dichloromethane (1500 ml), methanol (1500 ml) and the compound of formula II (100 gm) were charged at a temperature of 25-30° C. The reaction mixture was cooled to a temperature of 3-8 °C and to the reaction mixture, sulphuric acid (8.69 gm); n-propanal (13.98 ml) and sodium borohydride (2.46 g) were charged. The reaction mixture was stirred for 20-30 minutes at a temperature of 3-8°C. To the reaction mixture, n-propanal (41.94g) followed by sodium borohydride (7.38g) were added in three different lots at a temperature of 3-8°C. After completion of the reaction, the reaction mixture was quenched with brine solution. The quenched reaction mixture was further concentrated up to 15-16 volumes at 50-55°C under vacuum. The reaction mixture was cooled to 15-20°C. To the reaction mixture potassium carbonate (150 g), ethyl acetate (900 ml) and methanol (100 ml) were charged. The two layers formed were separated. The organic layer was then concentrated up to 7 to 8 volumes. To the organic layer ethyl acetate (500 ml) and brine solution (240 g) were added. The two layers formed were separated. The organic layer was treated with activated charcoal and filtered through hyflo. The organic layer was then concentrated under vacuum to obtain residue. To the obtained residue diisopropyl ether (200 ml) was added and reaction mixture was stirred for 20-30 minutes at 45-50°C. The reaction mixture was then cooled at 25-30°C to precipitate solid. The precipitated solid was then filtered and washed with diisopropyl ether (200ml) to obtain the compound of formula I.

Step B: Synthesis of monohydrochlonde salt of the compound of formula I:

To the reaction flask, the compound of formula I (as obtained in the step A) and isopropyl alcohol (900 ml) were charged and the reaction mixture was stirred at a temperature of 25-35°C for 1 hour. The reaction mixture was then filtered through hyflo and washed with isopropyl alcohol (100 ml). To the filtrate cone, hydrochloric acid (42.20 ml) was added to obtain a solid. The obtained solid was then filtered and washed with isopropyl alcohol (200 ml) to yield the monohydrochloride salt of the compound of formula I.

Step C: Purification of the monohydrochloride salt of the compound of formula I:

To the reaction flask, the monohydrochloride salt of the compound of formula I (as obtained in the step B) and the mixture of methanol (300 ml) and water (5.01 ml) were charged and the reaction mixture was stirred at a temperature of 55-60°C for 2 hours. The resulting reaction mixture was then cooled to a temperature of 20-25°C to precipitate solid. The precipitated solid was then filtered and washed with isopropyl alcohol (200 ml) to obtain the pure monohydrochloride salt of the compound of formula I.

Step D: Synthesis of the dihydrochloride monohydrate salt of the compound of formula I:

To the reaction flask, the pure monohydrochloride salt of the compound of formula I (as obtained in the step C), methanol (600 ml) and cone, hydrochloric acid (33.67 ml) were charged and the reaction mass was stirred at a temperature of 3-8°C for 2 hours. To the reaction mass, activated charcoal (4g) was charged and the reaction mass was stirred for 30-45 minutes at temperature of 40-50°C. The activated charcoal was filtered through hyflo and filtrate was concentrated under vacuum to obtain residue. To the residue, isopropyl alcohol (700 ml) was charged and the reaction mass was maintained for 2-3 hours at 15-20°C to precipitate solid. The precipitated solid was then filtered and washed with isopropyl alcohol (100 ml). The solid was then dried under vacuum to yield dihydrochloride monohydrate salt of the compound of formula I. Yield 36%, purity 99.77%.

Details for HPLC analysis:

Column: Inertsil ODS-3, 125 X 4.0 mm, 5μιη

Part No: C/N 5020

Mobile phase

Mobile phase A: Buffer solution

Mobile phase B: Acetonitrile: Buffer (500:500 v/v)

Flow rate: 1.5 ml/min

Injection volume: 5 μΐ

Run time: 25 minutes

Detector: 264 nm.

Column temperature: 40°C

Diluent: Acetonitrile: Buffer (200:800 v/v)

Procedure:

For system suitability inject (5μί) of the system suitability solution. The resolution between Pramipexole (the compound of formula I) related compound and Pramipexole should not be less than 6.0. The tailing factor for Pramipexole should not be more than 2.0. Inject Standard solution in six replicates into the chromatograph. For the Pramipexole peak, the relative standard deviation should not be more than 5.0%.

Inject (5μί) of blank preparation and test solution into the chromatograph, measure the responses of all the peaks and calculate all known impurities and unknown impurities by the formula given below. In the sample chromatogram disregard any peak due to the blank. Retention time and relative retention times are given in the table below.

Calculation :- SPL (Area) Cone STD

% impurities = X X 100

STD (Area) Cone SPL

Where:

SPL (Area) – is area of peak due to impurities in sample preparation.

STD (Area) – is mean area of peak of Pramipexole in reference solution (a) for injections.

Cone SPL – concentration of Pramipexole in test solution in mg/mL

Cone STD – concentration of Pramipexole in test solution in mg/mL

References

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National Prescribing Service (2009). “Pramipexole for Parkinson’s Disease”. Medicines Update. Available athttp://www.nps.org.au/consumers/publications/medicine_update/issues/Pramipexole_for_Parkinsons_disease
Kvernmo T, Härtter S, Burger E (August 2006). “A review of the receptor-binding and pharmacokinetic properties of dopamine agonists”. Clinical Therapeutics 28 (8): 1065–78.doi:10.1016/j.clinthera.2006.08.004. PMID 16982285.
Newman-Tancredi A, Cussac D, Audinot V, et al. (November 2002). “Differential actions of antiparkinson agents at multiple classes of monoaminergic receptor. II. Agonist and antagonist properties at subtypes of dopamine D(2)-like receptor and alpha(1)/alpha(2)-adrenoceptor”. The Journal of Pharmacology and Experimental Therapeutics 303 (2): 805–14.doi:10.1124/jpet.102.039875. PMID 12388667.
Millan MJ, Maiofiss L, Cussac D, Audinot V, Boutin JA, Newman-Tancredi A (November 2002). “Differential actions of antiparkinson agents at multiple classes of monoaminergic receptor. I. A multivariate analysis of the binding profiles of 14 drugs at 21 native and cloned human receptor subtypes”. The Journal of Pharmacology and Experimental Therapeutics 303 (2): 791–804. doi:10.1124/jpet.102.039867. PMID 12388666.
Weber, M; Chang W; Breier M; Ko D; Swerdlow NR (December 2008). “Heritable strain differences in sensitivity to the startle gating-disruptive effects of D2 but not D3 receptor stimulation”. Behav Pharmacol 19 (8): 786–795. doi:10.1097/FBP.0b013e32831c3b2b. PMC 3255557. PMID 19020413.
Chang, W; Weber M; Breier MR; Saint Marie RL; Hines SR; Swerdlow NR (February 2012). “Stereochemical and neuroanatomical selectivity of pramipexole effects on sensorimotor gating in rats”. Brain Res 1437: 69–76. doi:10.1016/j.brainres.2011.12.007. PMID 22227455.
Zarate CA, Payne JL, Singh J, et al. (July 2004). “Pramipexole for bipolar II depression: a placebo-controlled proof of concept study”. Biol. Psychiatry 56 (1): 54–60.doi:10.1016/j.biopsych.2004.03.013. PMID 15219473.
Corrigan MH, Denahan AQ, Wright CE, Ragual RJ, Evans DL (2000): Comparison of pramipexole, fluoxetine, and placebo in patients with major depression. Depress Anxiety 11:58 –65.
Jump up^ “MedlinePlus Drug Information: Pramipexole (Systemic)”. United States National Library of Medicine. Archived from the original on 2006-09-26. Retrieved 2006-09-27.
“FDA Prescribing Information: Mirapex (pramipexole dihydrochloride)” (PDF). Food and Drug Administration (United States). Retrieved 2008-12-31.
Wolters ECh, van der Werf YD, van den Heuvel OA (September 2008). “Parkinson’s disease-related disorders in the impulsive-compulsive spectrum”. J. Neurol. 255 Suppl 5: 48–56.doi:10.1007/s00415-008-5010-5. PMID 18787882.
Jump up^ Bostwick JM, Hecksel KA, Stevens SR, Bower JH, Ahlskog JE (April 2009). “Frequency of new-onset pathologic compulsive gambling or hypersexuality after drug treatment of idiopathic Parkinson disease”. Mayo Clin. Proc. 84 (4): 310–6. doi:10.4065/84.4.310. PMC 2665974. PMID 19339647.
Jump up^ Schneider, C. S.; Mierau, J. (1987). “Dopamine autoreceptor agonists: Resolution and pharmacological activity of 2,6-diaminotetrahydrobenzothiazole and an aminothiazole analog of apomorphine”. Journal of Medicinal Chemistry 30 (3): 494–8. doi:10.1021/jm00386a009. PMID 3820220.
Jump up^ DeBattista C, Solvason HB, Breen JA, Schatzberg AF. (2000). “Pramipexole augmentation of a selective serotonin reuptake inhibitor in the treatment of depression.”. J Clin Psychopharmacol. 20 (2): 274–275. doi:10.1097/00004714-200004000-00029. PMID 10770475.
Jump up^ Goldberg JF, Burdick KE, Endick CJ (March 2004). “Preliminary, randomized, double-blind, placebo-controlled trial of pramipexole added to mood stabilizers for treatment resistant bipolar depression.”. American Journal of Psychiatry 161 (3): 161:564–566. doi:10.1176/appi.ajp.161.3.564. PMID 14992985.
Jump up^ Guy M. Goodwina, A. Martinez-Aranb, David C. Glahn c, Eduard Vieta b (November 2008). “Cognitive impairment in bipolar disorder: Neurodevelopment or neurodegeneration? An ECNP expert meeting report”. European Neuropsychopharmacology 18 (11): 787–793. doi:10.1016/j.euroneuro.2008.07.005. PMID 18725178.
Lattanzi L, Dell’Osso L, Cassano P, Pini S, Rucci P, Houck PR, Gemignani A, Battistini G, Bassi A, Abelli M, Cassano GB. (2002). “Pramipexole in treatment-resistant depression: a 16-week naturalistic study.”. Bipolar Disord. 4 (5): 307–314. doi:10.1034/j.1399-5618.2002.01171.x. PMID 12479663.
Cassano P, Lattanzi L, Soldani F, Navari S, Battistini G, Gemignani A, Cassano GB. (2004). “Pramipexole in treatment-resistant depression: an extended follow-up.”. Depression and Anxiety20 (3): 131–138. doi:10.1002/da.20038. PMID 15549689.
Holman AJ, Myers RR. (2005). “A randomized, double-blind, placebo-controlled trial of pramipexole, a dopamine agonist, in patients with fibromyalgia receiving concomitant medications.”.Arthritis Rheum. 52 (8): 2495–2505. doi:10.1002/art.21191. PMID 16052595.

External links

Mirapex.com – Manufacturer’s website

WO2006003677A1 *	Apr 25, 2005	Jan 12, 2006	Alembic Ltd	Improved process for the preparation of biologically active tetrahydrobenzthiazole derivative
EP0186087A1 *	Dec 16, 1985	Jul 2, 1986	Dr. Karl Thomae GmbH	Tetrahydro-benzothiazoles, their production and their use as intermediates or drugs
EP0207696A1 *	Jun 20, 1986	Jan 7, 1987	Eli Lilly And Company	Dialkylaminotetrahydrobenzothiazoles and oxazoles
EP1731514A1 *	Jun 2, 2005	Dec 13, 2006	Sandoz AG	Process for the preparation of Pramipexole

BOEHRINGER INGELHEIM: “Mirapex“[Online] 2006, pages 4-31, XP002444888 Retrieved from the Internet: URL:http://www.fda.gov/medwaTCH/safety/200 6/Nov_PIs/Mirapex_PI.pdf>
2	*	SCHNEIDER C S ET AL: “Dopamine autoreceptor agonists: resolution and pharmacological activity of 2,6-diaminotetrahydrobenzothiazole and aminothiazole analogue of apomorphine” JOURNAL OF MEDICINAL CHEMISTRY, AMERICAN CHEMICAL SOCIETY. WASHINGTON, US, vol. 30, no. 3, March 1987 (1987-03), pages 494-498, XP002186199 ISSN: 0022-2623 cited in the application

Citing Patent	Filing date	Publication date	Applicant	Title
EP2137171A2 *	Mar 14, 2008	Dec 30, 2009	Knopp Neurosciences, Inc.	Synthesis of chirally purified substituted benzothiazole diamines

Pramipexole
Systematic (IUPAC) name


(S)-N ⁶-propyl-4,5,6,7-tetrahydro-1,3-benzothiazole-2,6-diamine
Clinical data
Trade names	Mirapex, Mirapexin, Sifrol
AHFS/Drugs.com	monograph
MedlinePlus	a697029
Pregnancy category	AU: B3 US: C (Risk not ruled out)
Legal status	℞ (Prescription only)
Routes of administration	Oral
Pharmacokinetic data
Bioavailability	>90%
Protein binding	15%
Biological half-life	8–12 hours
Excretion	Urine (90%), Feces(2%)
Identifiers
CAS Registry Number	104632-26-0
ATC code	N04BC05
PubChem	CID: 119570
IUPHAR/BPS	953
DrugBank	DB00413
ChemSpider	106770
UNII	83619PEU5T
KEGG	D05575
ChEBI	CHEBI:8356
ChEMBL	CHEMBL301265
Chemical data
Formula	C₁₀H₁₇N₃S
Molecular mass	211.324 g/mol

///////////

Update………..

. Compound 1 1H NMR (CD3OD, 300 MHz): δ 3.36–3.41 (m, 1H), 2.70–2.92 (m, 2H), 2.53–2.67 (m, 2H), 2.32–2.40 (m, 1H), 1.78–1.92 (m, 1H), 1.48–1.61 (m, 2H), 0.93 (td, J = 1.1 Hz, 7.4 Hz, 3H).

13C NMR (CD3OD, 100 MHz): 184.04, 178.19, 170.88, 117.92, 61.24, 26.85, 20.83, 11.23.

http://pubs.acs.org/doi/abs/10.1021/acs.oprd.6b00182

Synthesis of Impurities of Pramipexole Dihydrochloride

Tianwen Hu^†^‡∥, Feipu Yang^†^‡∥, Tao Jiang^†^‡, Weiming Chen^§, Jian Zhang^§, Jianfeng Li^†, Xiangrui Jiang^*^†, andJingshan Shen^†

^† CAS Key Laboratory of Receptor Research, Drug Discovery and Design Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), 555 Zuchongzhi Road, Shanghai 201203, China

^‡ University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, China

^§ Topharman Shanghai Co. Ltd., Shanghai 201209, China

Org. Process Res. Dev., Article ASAP

DOI: 10.1021/acs.oprd.6b00182

*Fax: +86-21-20231000-2407. Telephone: +86-21-2023100-2407. E-mail: jiangxiangrui@simm.ac.cn.

Abstract

Three impurities of pramipexole dihydrochloride were synthesized, and the possible generation mechanisms and the preparation methods of some impurities were reviewed. The desired configuration at C7 of 3 was built by a Mitsunobu reaction.

Abemaciclib (Bemaciclib)

October 19, 2015 5:00 am / 1 Comment on Abemaciclib (Bemaciclib)

Abemaciclib (Bemaciclib)

N-[5-[(4-ethylpiperazin-1-yl)methyl]pyridin-2-yl]-5-fluoro-4-(7-fluoro-2-methyl-3-propan-2-ylbenzimidazol-5-yl)pyrimidin-2-amine

2-Pyrimidinamine, N-(5-((4-ethyl-1-piperazinyl)methyl)-2-pyridinyl)-5-fluoro-4-(4-fluoro-2-methyl-1-(1-methylethyl)-1H-benzimidazol-6-yl)

[5-(4-Ethyl-piperazin-1-ylmethyl)-pyridin-2-yl]-[5-fluoro-4-(7-fluoro-3-isopropyl-2-methyl-3H-benzoimidazol-5-yl)-pyrimidin-2-yl]-amine

C₂₇H₃₂F₂N₈
M.W.	506.59

Abemaciclib; 1231929-97-7; LY2835219; LY2835219 free base; UNII-60UAB198HK; LY 2835219 (free base);

Treatment of Advanced Cancer

Abemaciclib is an orally available cyclin-dependent kinase (CDK) inhibitor that targets the CDK4 (cyclin D1) and CDK6 (cyclin D3) cell cycle pathway, with potential antineoplastic activity. Abemaciclib specifically inhibits CDK4 and 6, thereby inhibiting retinoblastoma (Rb) protein phosphorylation in early G1. Inhibition of Rb phosphorylation prevents CDK-mediated G1-S phase transition, thereby arresting the cell cycle in the G1 phase, suppressing DNA synthesis and inhibiting cancer cell growth. Overexpression of theserine/threonine kinases CDK4/6, as seen in certain types of cancer, causes cell cycle deregulation.

LY2835219 is a potent and selective inhibitor of CDK4 and CDK6 with IC50 of 2 nM and 10 nM, respectively.
IC50 Value: 2 nM(CDK4); 10 nM(CDK6)
Target: CDK4/6
in vitro: LY2835219 is an orally available cyclin-dependent kinase (CDK) inhibitor that targets the CDK4 (cyclin D1) and CDK6 (cyclin D3) cell cycle pathway, with potential antineoplastic activity. LY2835219 specifically inhibits CDK4 and 6, thereby inhibiting retinoblastoma (Rb) protein phosphorylation in early G1. Inhibition of Rb phosphorylation prevents CDK-mediated G1-S phase transition, thereby arresting the cell cycle in the G1 phase, suppressing DNA synthesis and inhibiting cancer cell growth. Overexpression of the serine/threonine kinases CDK4/6, as seen in certain types of cancer, causes cell cycle deregulation.
in vivo: LY2835219 saturates BBB efflux with an unbound plasma IC50 of about 95 nM. The percent of dose in brain for LY2835219-MsOH is 0.5–3.9%. In both a subcutaneous and intracranial human glioblastoma model (U87MG), LY2835219-MsOH suppressed tumor growth in a dose-dependent manner both as a single agent, and in combination with temozolomide.

LY2835219 Methane sulfonate

cas 1231930-82-7, C28H36F2N8O3S, 602.7

SYNTHESIS

US20100160340

Example 1

[0112]
Bubble nitrogen into a mixture of 6-(2-chloro-5-fluoro-pyrimidin-4-yl)-4-fluoro-1-isopropyl-2-methyl-1H-benzoimidazole (15.9 g), 5-(4-ethyl-piperazin-1-ylmethyl)-pyridin-2-ylamine (10.85 g), cesium carbonate (32.10 g), tris(dibenzylideneacetone) dipalladium (1.82 g), 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (2.35 g) in 1,4-dioxane (197.06 mL). Heat the mixture in a pre-heated oil bath at 110° C. for 2 h. Cool to RT, dilute with DCM and filter over a celite pad. Remove the solvent under vacuum and purify by silica gel column chromatography, eluting with DCM/methanol (2%) and then DCM/methanol-NH₃2 M 2% to afford 22.11 g of the title compound. MS (ES⁺): m/z=507 (M+H)⁺.

Example 33

[0135]

a. 1-(6-Bromo-pyridin-3-ylmethyl)-4-ethyl-piperazine

Add neat 1-ethylpiperazine (5.6 kg) to a mixture of 6-bromo-pyridine-3-carbaldehyde (8.3 kg) and DCM (186 kg). Then, add sodium triacetoxyborohydride (10.9 kg) in portions and stir at 20-30° C. for 12 h. Quench the reaction into a mixture of DCM (36 kg) and aqueous solution of sodium hydroxide 2 N (46 kg). Separate the layers and extract twice the aqueous layer with DCM (24×2 kg). Combine the organic layers, wash with brine (50×2 kg) and remove the solvent under vacuum to afford 11.5 kg of the title compound. MS (ES⁺): m/z=285 (M+H)⁺.

b. 5-(4-Ethyl-piperazin-1-ylmethyl)-pyridin-2-ylamine

Add liquid ammonia (50.0 kg) to a degassed mixture of 1-(6-bromo-pyridin-3-ylmethyl)-4-ethyl-piperazine (14.2 kg), cuprous oxide (200 g), and MeOH (57 kg) at T≦40° C. Heat the mixture at 65-75° C. overnight. Cool to 20-30° C. and filter over a Celite® pad. Concentrate the filtrate and add DCM (113 kg) and adjust the pH to 12-14 with sodium hydroxide 2N (23 kg) separate the phases and wash the organic phase with DCM (58×2 kg) and combine the organic layers. Filter the mixture through Celite® and concentrate. Dissolve the residue in toluene (9.7 kg) and crystallize by the addition of MtBE (8.3 kg) to give 6.0 kg of the title compound. Obtain further purification through a toluene recrystallization. MS (ES⁺): m/z=221 (M+H)⁺.

c. N-Isopropyl-acetamide

Add potassium carbonate (28 kg) to a solution of 2-propanamine (12 kg) in ethyl acetate (108 kg) at <20° C. Cool the mixture to 5-0° C. and add acetyl chloride (16.7 kg) at about 2-3 kg/h. Stir until complete by gas chromatography. Quench the reaction with water (0.8 kg) and filter the reaction mixture and concentrate to afford 13.4 kg of the title compound. NMR (CDCl₃) 4.06 (m, 1H), 1.94 (s, 3H), 1.14 (d, 6H).

d. N-(4-Bromo-2,6-difluoro-phenyl)-N′-isopropyl-acetamidine

Add phosphoryl chloride (16.0 kg) to a mixture of 4-bromo-2,6-difluoro-phenylamine (14.5 kg), N-isopropyl acetamide (8.5 kg), TEA (10.6 kg) in toluene (115 kg) at <20° C. Stir at 10-20° C. until complete by HPLC. Remove the solvent under vacuum and add MtBE (64 kg). Adjust the pH of the mixture with 10% aq. sodium carbonate (250 kg). Filter the mixture and rinse the cake with MtBE (11×2 kg). Separate the phases and wash the aqueous layer with MtBE (22×2 kg). Combine the organic layers and concentrate, filter and wash with cyclohexane (0.6 kg) and dry to afford 17.2 kg of the title compound. MS (ES⁺): m/z=292 (M+H)⁺.

e. 6-Bromo-4-fluoro-1-isopropyl-2-methyl-1H-benzoimidazole

Add potassium tert-butoxide (6.9 kg) in portions to a solution of N-(4-bromo-2,6-difluoro-phenyl)-N′-isopropyl-acetamidine (16.2 kg) in N-methyl formamide (76 kg) while maintaining the temperature at T<30° C. Heat the mixture at 70-75° C. until complete by HPLC. Cool to 20-30° C. and quench by adding into water (227 kg) then extract with MtBE (37×4 kg). Wash the combined organic phases with brine (49×2 kg) and concentrate to 25-30 L, add n-hexane (64 kg) and filter the slurry to give 11 kg of the title compound. MS (ES⁺): m/z=272 (M+H)⁺.
Obtain additional purification by dissolving the crude compound in DCM and filtering through a silica gel and Celite® pad followed by isolation from an MtBE/hexane mixture.

f. 4-Fluoro-1-isopropyl-2-methyl-6-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-1H-benzoimidazole

Bubble nitrogen into a mixture of 6-bromo-4-fluoro-1-isopropyl-2-methyl-1H-benzoimidazole (600 g), bis(pinacolato)diboron (843 g), tricyclohexylphosphine (106 g), potassium acetate (652 g), and DMSO (3.6 L). Add palladium acetate (49 g) and heat at 100° C. until complete by HPLC. Cool the reaction mixture and dilute with water (18 L), then filter to isolate the solid. Dissolve the crude material in 1,2-dimethoxyethane (450 mL) and filter through Celite®. Use the filtrate directly in part g.

g. 6-(2-Chloro-5-fluoro-pyrimidin-4-yl)-4-fluoro-1-isopropyl-2-methyl-1H-benzoimidazole

Bubble nitrogen into a mixture of 2,4-dichloro-5-fluoro-pyrimidine (517 g), sodium carbonate (586 g) in water (1.7 L) and 1,2-dimethoxyethane (3.4 L). Add bis(triphenylphosphine)palladium(II) chloride (4.9 g) and heat the reaction at 80±3° C. and add drop wise a solution of 4-fluoro-1-isopropyl-2-methyl-6-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-1H-benzoimidazole in 1,2-dimethoxyethane from part f (5.1 L). Stir the mixture at 80±3° C. until complete by HPLC. Cool to RT and dilute with cold water (2.1 L, 5° C.). Stir for 1 hour then isolate the crude solid by filtration. Achieve further purification of the solid by trituration with IPA to give 472 g of the title compound. MS (ES⁺): m/z=323 (M+H)⁺.

h. [5-(4-Ethyl-piperazin-1-ylmethyl)-pyridin-2-yl]-[5-fluoro-4-(7-fluoro-3-isopropyl-2-methyl-3H-benzoimidazol-5-yl)-pyrimidin-2-yl]-amine Crystalline form III

[0144]
Bubble nitrogen into a mixture of 6-(2-chloro-5-fluoro-pyrimidin-4-yl)-4-fluoro-1-isopropyl-2-methyl-1H-benzoimidazole (465 g), 5-(4-ethyl-piperazin-1-ylmethyl)-pyridin-2-ylamine (321 g), potassium carbonate (403 g), 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (17 g) in t-amyl alcohol (2.3 L). Heat tris(dibenzylideneacetone) dipalladium (13.2 g) and the mixture at 100±5° C. until complete by HPLC. Cool to RT, dilute with DCM (1.2 L) and filter over a Celite® pad. Extract the filtrate with 4M HCl (2.3 L×2). Combine the aqueous layers and stir with charcoal (32 g). Filter through Celite®, add DCM (1.7 L) and adjust pH with NaOH (28% aq., 1.5 L). Collect the organic layer and wash the aqueous layer with DCM (1.7 L). Combine organic layers, wash with brine (1 L), and dry over magnesium sulphate. Use a solid supported Si-Thiol treatment to remove residual palladium and the solvent is exchanged to acetone. Filter the slurry and dry to give 605 g of crude product as Form I. Mix 605 g of Form I and 4.3 L of dry acetone. Slurry the suspension at 56-57° C. (reflux) for at least 18 hours and then at ambient temperature for 4 hours. Isolate the solid by vacuum filtration, producing a light yellow cake. Dry the solid in a vacuum oven at 35° C. until a constant weight of 570 g is obtained. Confirm the material by XRPD to be Form III of the title compound. MS (ES+): m/z=507 (M+H)⁺.

Synthesis….http://www.joygooo.com/news_110.htm?pageNum=21

OTHERS


Patent	Submitted	Granted
PROTEIN KINASE INHIBITORS [US7855211]	2010-06-24	2010-12-21
Human papilloma virus as predictor of cancer prognosis [US8673972]	2013-08-02	2014-03-18
HUMAN PAPILLOMA VIRUS AS PREDICTOR OF CANCER PROGNOSIS [US2015030587]	2014-02-11	2015-01-29

/////////LY 2835219, Abemaciclib, Bemaciclib

CCN1CCN(CC1)Cc2ccc(nc2)Nc3ncc(c(n3)c4cc5c(c(c4)F)nc(n5C(C)C)C)F

Ribociclib, рибоциклиб , ريبوسيكليب , 瑞波西利

October 19, 2015 3:40 am / 1 Comment on Ribociclib, рибоциклиб , ريبوسيكليب , 瑞波西利

str0

Ribociclib

рибоциклиб , ريبوسيكليب , 瑞波西利

Ribociclib (LEE 011)
CAS: 1211441-98-3

Chemical Formula: C23H30N8O
Exact Mass: 434.25426

7-Cyclopentyl-2-(5-piperazin-1-yl-pyridin-2-ylamino)-7H-pyrrolo[2,3-d]pyrimidine-6-carboxylic acid dimethylamide

FDA UNII

TK8ERE8P56

Current developer: Novartis /Astex Pharmaceuticals.

Novartis Ag, Astex Therapeutics Ltd.

NMR.http://file.selleckchem.com/downloads/nmr/S744002-LEE011-2-HNMR-Selleck%20.pdf

http://file.selleckchem.com/downloads/hplc/S744002-LEE011-2-HPLC-Selleck.pdf

Ribociclib (LEE011) is an orally available, and highly specific CDK4/6 inhibitor. Phase 3.

CDK4 AND 6
(Cell-free assay)Product Ingredients

NOW FDA APPROVED 2017 since the blog post was written

Kisqali		FDA 3/13/2017	To treat postmenopausal women with a type of advanced breast cancer Drug Trials Snapshot

Image result for RIBOCICLIB

INGREDIENT	UNII	CAS	INCHI KEY
Ribociclib hydrochloride	63YF7YKW7E	1211443-80-9	JZRSIQPIKASMEV-UHFFFAOYSA-N
Ribociclib succinate	BG7HLX2919	1374639-75-4	NHANOMFABJQAAH-UHFFFAOYSA-N

ChemSpider 2D Image | Ribociclib succinate | C27H36N8O5

RIBOCICLIB SUCCINATE

STRUCTURE ….LINK

Ribociclib is in phase III clinical trials by Novatis for the treatment of postmenopausal women with advanced breast cancer.

Phase II clinical trials are also in development for the treatment of liposarcoma, ovarian cancer, fallopian tube cancer, peritoneum cancer, endometrial cancer, and gastrointestinal cancer.

Ribociclib, also known as LEE011, is an orally available cyclin-dependent kinase (CDK) inhibitor targeting cyclin D1/CDK4 and cyclin D3/CDK6 cell cycle pathway, with potential antineoplastic activity. CDK4/6 inhibitor LEE011 specifically inhibits CDK4 and 6, thereby inhibiting retinoblastoma (Rb) protein phosphorylation. Inhibition of Rb phosphorylation prevents CDK-mediated G1-S phase transition, thereby arresting the cell cycle in the G1 phase, suppressing DNA synthesis and inhibiting cancer cell growth. Overexpression of CDK4/6, as seen in certain types of cancer, causes cell cycle deregulation

Orally bioavailable CDK4/6-selective inhibitor that has been tested in Phase III clinical trials for treatment of advanced breast cancer.

CDK full name of cyclin-dependent kinases, there are many other subtypes CDK1-11, capable of binding to cell cycle proteins regulate the cell cycle. Pfizer Palbociclib been submitted for FDA review under phase II clinical data, Novartis Ribociclib (LEE011), Lilly Abemaciclib (LY2835219) the three CDK4 / 6 inhibitors have entered late stage development for the treatment of breast cancer

SYNTHESIS

WO2010020675
US20120115878

WO2010020675

http://www.google.co.in/patents/WO2010020675A1?cl=en

Example 74

7-Cyclopentyl-2-(5-piperazin-1-yl-pyridin-2-ylamino)-7H-pyrrolo[2,3-d]pyrimidine-6-carboxylic acid dimethylamide

Following Buchwald Method B, then General Procedure A, 2-chloro-7-cyclopentyl-7H- pyrrolo[2,3-d]pyrimidine-6-carboxylic acid dimethylamide (300 mg, 1.02 mmol) and 5-piperazin-1- yl-pyridin-2-ylamine (314 mg, 1.13 mmol) gave 7-cyclopentyl-2-(5-piperazin-1-yl-pyridin-2- ylamino)-7H-pyrrolo[2,3-d]pyrimidine-6-carboxylic acid dimethylamide (142 mg, 36%). MS(ESI) m/z 435.3 (M+H)⁺

POSTER

str1

SYNTHESIS

str1

Image result for RIBOCICLIB joygooo

TAKEN FROM ….http://www.joygooo.com/news_71.htm?pageNum=21

PCT Int Appl, WO2012061156.

US Pat Appl Publ, US20120115878

PCT Int Appl, WO2011130232 5) Brain, Christopher Thomas et al; Preparation of pyrrolopyrimidine Derivatives for Use as CDK4 / 6 inhibitors;. PCT Int Appl, WO2011101409.

PCT Int Appl, WO2011101417. 7) Besong, Gilbert et al;.

PCT Int Appl, WO2010020675.

PCT Int Appl, WO2007140222.

Route 1

Reference：1. WO2012064805A1 / US20120115878A1.

2. WO2010020675A1 / US8415355B2.

3. WO2011130232A1 / US20130035336A1.

Clinical Trial Information( data from http://clinicaltrials.gov, updated on 2015-10-17)

NCT Number	Recruitment	Conditions	Sponsor /Collaborators	Start Date	Phases
NCT02571829	Not yet recruiting	Liposarcoma\|Soft Tissue Sarcoma	Hadassah Medical Organization	December 2015	Phase 2
NCT02524119	Not yet recruiting	Hepatocellular Carcinoma	University of Texas Southwestern Medical Center\|Novartis …more	November 2015	Phase 2
NCT02494921	Recruiting	Prostate Cancer	Rahul Aggarwal\|University of California, San Francisco	September 2015	Phase 1\|Phase 2
NCT02420691	Recruiting	Gastrointestinal Cancer	M.D. Anderson Cancer Center\|Novartis	August 2015	Phase 2
NCT02431481	Not yet recruiting	Normal Renal Function\|Impaired Renal Function	Novartis Pharmaceuticals\|Novartis	August 2015	Phase 1

Protocols from literature

In vitro protocol::

Pharmacologic growth inhibition: Clin Cancer Res. 2013 Nov 15;19(22):6173-82.

Cell-cycle analysis: Clin Cancer Res. 2013 Nov 15;19(22):6173-82.

Senescence and apoptosis assays: Clin Cancer Res. 2013 Nov 15;19(22):6173-82.

In vivo protocol:

Xenograft therapeutic trials: Clin Cancer Res. 2013 Nov 15;19(22):6173-82

Immunohistochemistry of xenografted neuroblastomas.Clin Cancer Res. 2013 Nov 15;19(22):6173-82

Ribociclib (LEE011) is a Me-Too version of palbociclib. Their structures are compared side-by-side as the following:

Ribociclib (LEE011) is currently being developed by Novartis and Astex. According its Novartis’s website, LEE011 is a novel, orally available, selective inhibitor of CDK4/6 kinases, which induces complete dephosphorylation of Rb and G1 arrest in cancer cells. In preclinical in vitro and in vivo tumor models, LEE011 has been shown active in cancers harboring aberrations that increase CDK4/6 activity, including those directly linked to the kinases as well as activating alterations in the upstream regulators. First-in-human study of LEE011 in patients with solid tumors and lymphoma is currently ongoing. (source: http://www.novartisoncology.us/research/pipeline/lee011.jsp).

Treatment with LEE011 significantly reduced proliferation in 12 of 17 human neuroblastoma-derived cell lines by inducing cytostasis at nanomolar concentrations (mean IC50 = 307 ± 68 nmol/L in sensitive lines). LEE011 caused cell-cycle arrest and cellular senescence that was attributed to dose-dependent decreases in phosphorylated RB and FOXM1, respectively. In addition, responsiveness of neuroblastoma xenografts to LEE011 translated to the in vivo setting in that there was a direct correlation of in vitro IC50 values with degree of subcutaneous xenograft growth delay. Although our data indicate that neuroblastomas sensitive to LEE011 were more likely to contain genomic amplification of MYCN (P = 0.01), the identification of additional clinically accessible biomarkers is of high importance. LEE011 is active in a large subset of neuroblastoma cell line and xenograft models, and supports the clinical development of this CDK4/6 inhibitor as a therapy for patients with this disease. (Clin Cancer Res. 2013 Nov 15;19(22):6173-82)

References

1. Rader J, Russell MR, Hart LS, Nakazawa MS, Belcastro LT, Martinez D, Li Y, Carpenter EL, Attiyeh EF, Diskin SJ, Kim S, Parasuraman S, Caponigro G, Schnepp RW, Wood AC, Pawel B, Cole KA, Maris JM. Dual CDK4/CDK6 inhibition induces cell-cycle arrest and senescence in neuroblastoma. Clin Cancer Res. 2013 Nov 15;19(22):6173-82. doi: 10.1158/1078-0432.CCR-13-1675. Epub 2013 Sep 17. PubMed PMID: 24045179; PubMed Central PMCID: PMC3844928.

2. Caponigro, Giordano; Stuart, Darrin; Kim, Sunkyu; Loo, Alice; Delach, Scott. Pharmaceutical combinations of a CDK4/6 inhibitor and a B-RAF inhibitor for treatment of proliferative diseases such as cancer. PCT Int. Appl. (2014), WO 2014018725 A1 20140130.

3. Kim, Sunkyu; Doshi, Shivang; Haas, Kristy; Kovats, Steven; Huang, Alan Xizhong; Chen, Yan. Combination therapy comprising a cyclin dependent kinase 4/6 (CDK4/6) inhibitor and a phosphatidylinositol 3-kinase (PI3K) inhibitor for use in the treatment of cancer. PCT Int. Appl. (2013), WO 2013006532 A1 20130110

4. Kim, Sunkyu; Doshi, Shivang; Haas, Kristy; Kovats, Steven. Combination of cyclin dependent kinase 4/6 (CDK4/6) inhibitor and fibroblast growth factor receptor (FGFR) kinase inhibitor for the treatment of cancer. PCT Int. Appl. (2013), WO 2013006368 A1 20130110

5. Calienni, John Vincent; Chen, Guang-Pei; Gong, Baoqing; Kapa, Prasad Koteswara; Saxena, Vishal. Salt(s) of 7-cyclopentyl-2-(5-piperazin-1-yl-pyridin-2-ylamino-7H-pyrrolo[2,3-d]pyrimidine-6-carboxylic acid dimethylamide and processes of making thereof. U.S. Pat. Appl. Publ. (2012), US 20120115878 A1 20120510.

6. Borland, Maria; Brain, Christopher Thomas; Doshi, Shivang; Kim, Sunkyu; Ma, Jianguo; Murtie, Josh; Zhang, Hong. Combination comprising a cyclin dependent kinase 4 or cyclin dependent kinase (cdk4/6) inhibitor and an Mtor inhibitor for treating cancer. PCT Int. Appl. (2011), WO 2011130232 A1 20111020

7. Besong, Gilbert; Brain, Christopher Thomas; Brooks, Clinton A.; Congreve, Miles Stuart; Dagostin, Claudio; He, Guo; Hou, Ying; Howard, Steven; Li, Yue; Lu, Yipin; et al. Preparation of pyrrolopyrimidine compounds as CDK inhibitors. PCT Int. Appl. (2010), WO 2010020675 A1 20100225.

CLIP

Cyclin-dependent kinase inhibitors (14 compounds) under clinical evaluation.

Molecules 19 14366 g002 1024

LEE-011 is one of the most selective inhibitors for CDK4 and CDK6 [59] and is being developed by Astex Pharmaceuticals™ and Novartis. In January 2014 this inhibitor entered phase III clinical trials for the treatment of breast cancer [60]. Due to encouraging results LEE-011 has now become the main competing drug-candidate with Pfizer’s PD0332991 (palbociclib), see Figure 3 [59].

Figure 3. Comparison of Astex/Novartis’ LEE-011 and Pfizer’s PD0332991 structures.

Upon comparison of the chemical structure of Novartis’ LEE-011 and Pfizer’s PD0332991, the similarity is evident. The major difference lies in the bicyclic core since LEE-011 possesses a pyrrolo-pyrimidine and PD0332991 a pyridopyrimidine. The “east” part of the structure is also modified. The structural similarities make their analogous CDKs inhibition profiles (high selectivity for CDK4 and CDK6) quite obvious Moreover, both derivatives are orally administered which is pretty advantageous compared with dinaciclib, which is also in phase III clinical trials but is administered intravenously.

http://www.mdpi.com/1420-3049/19/9/14366/htm

Kurt, S. LEE011 CDK Inhibitor Showing Early Promise in Drug-Resistant Cancers. Oncol. Times 2014, 36, 39–40. [Google Scholar]
Macmillan Publishers Limited. CDK inhibitors speed ahead. Nat. Rev. Drug Discov. 2014, 13, 323. [Google Scholar] [CrossRef]

Sources:
1)Rader, JulieAnn et al.;Dual CDK4/CDK6 Inhibition Induces Cell-Cycle Arrest and Senescence in Neuroblastoma;Clinical Cancer Research (2013), 19(22), 6173-6182

2)Tavares, Francis X. and Strum, Jay C.;Preparation of pyrazinopyrrolopyrimidine derivatives and analogs for use as CDK inhibitors;PCT Int. Appl., WO2012061156

3)Calienni, John Vincent et al.;Salt(s) of 7-cyclopentyl-2-(5-piperazin-1-yl-pyridin-2-ylamino)-7H-pyrrolo[2,3-d]pyrimidine-6-carboxylic acid dimethylamide and processes of making thereof;U.S. Pat. Appl. Publ., US20120115878

4)Borland, Maria et al;Combination comprising a cyclin dependent kinase 4 or cyclin dependent kinase (cdk4/6) inhibitor and an Mtor inhibitor for treating cancer;PCT Int. Appl., WO2011130232

5)Brain, Christopher Thomas et al;Preparation of pyrrolopyrimidine derivatives for use as CDK4/6 inhibitors;PCT Int. Appl., WO2011101409

6)Brain, Christopher Thomas and Perez, Lawrence Blas; Preparation of deuterated pyrrolopyrimidine compounds as inhibitors of CDK4/6 for treating cancer; PCT Int. Appl., WO2011101417

7)Besong, Gilbert et al.;Preparation of pyrrolopyrimidine compounds as CDK inhibitors;PCT Int. Appl., WO2010020675

8)Brain, Christopher Thomas et al.;Preparation of pyrrolopyrimidine compounds as protein kinase inhibitors; PCT Int. Appl., WO2007140222

9)A Randomized Double-blind, Placebo-controlled Study of LEE011 in Combination With Letrozole for the Treatment of Postmenopausal Women With Hormone Receptor Positive, HER2 Negative, Advanced Breast Cancer Who Received no Prior Therapy for Advanced Disease;ClinicalTrials.gov Identifier: NCT01958021

/////////Ribociclib, novartis, LEE011, astex, phase 3, CDK inhibitors

CN(C)C(=O)c1cc2cnc(nc2n1C3CCCC3)Nc4ccc(cn4)N5CCNCC5

VARDENAFIL

October 18, 2015 12:48 pm / 1 Comment on VARDENAFIL

VARDENAFIL

224785-90-4^{CAS NO}

Vardenafil hydrochloride (CAS NO.224785-91-5)

Formula	C₂₃H₃₂N₆O₄S
Mol. mass	488.604 g/mol

4-[2-Ethoxy-5-(4-ethylpiperazin-1-yl)sulfonyl-phenyl]-9-methyl-7-propyl-3,5,6,8-tetrazabicyclo[4.3.0]nona-3,7,9-trien-2-one

Vivanza, Vardenafil (INN), Levitra (TN), STK642629, , LEVITRA

Vardenafil (INN) is a PDE5 inhibitor used for treating erectile dysfunction that is sold under the trade names Levitra (Bayer AG, GSK, and SP) andStaxyn.

Vardenafil was co-marketed by Bayer Pharmaceuticals, GlaxoSmithKline, and Schering-Plough under the trade name Levitra. As of 2005, the co-promotion rights of GSK on Levitra have been returned to Bayer in many markets outside the U.S. In Italy, Bayer sells vardenafil as Levitra and GSK sells it as Vivanza. Thus, because of European Union trade rules, parallel imports might result in Vivanza sold next to Levitra in the EU.

Vardenafil (Levitra) is an oral therapy for the treatment of erectile dysfunction. It is a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5). Penile erection is a hemodynamic process initiated by the relaxation of smooth muscle in the corpus cavernosum and its associated arterioles. During sexual stimulation, nitric oxide is released from nerve endings and endothelial cells in the corpus cavernosum. Nitric oxide activates the enzyme guanylate cyclase resulting in increased synthesis of cyclic guanosine monophosphate (cGMP) in the smooth muscle cells of the corpus cavernosum. The cGMP in turn triggers smooth muscle relaxation, allowing increased blood flow into the penis, resulting in erection. The tissue concentration of cGMP is regulated by both the rates of synthesis and degradation via phosphodiesterases (PDEs). The most abundant PDE in the human corpus cavernosum is the cGMPspecific phosphodiesterase type 5 (PDE5); therefore, the inhibition of PDE5 enhances erectile function by increasing the amount of cGMP.

An orally disintegrating form, marketed as Staxyn, has been gaining approvals in countries such as the United States^[1] and Canada.^[2]

Vardenafil’s indications and contra-indications are the same as with other PDE5 inhibitors; it is closely related in function to sildenafil citrate (Viagra) and tadalafil (Cialis). The difference between the vardenafil molecule and sildenafil citrate is a nitrogen atom’s position and the change of sildenafil’spiperazine ring methyl group to an ethyl group. Tadalafil is structurally different from both sildenafil and vardenafil. Vardenafil’s relatively short effective time is comparable to but somewhat longer than sildenafil’s.

Beyond its indications for erectile dysfunction, vardenafil may be effective in the treatment of premature ejaculation, where it may significantly increase the time from vaginal penetration to ejaculation.^[3]

The common, adverse drug reactions (side-effects) are the same as with other PDE5 inhibitors. The frequent vardenafil-specific side-effect is nausea; the infrequent side-effects are abdominal pain, back pain, photosensitivity, abnormal vision, eye pain, facial edema, hypotension, palpitation,tachycardia, arthralgia, myalgia, rash, itch, and priapism.

One possibly serious, but rare, side-effect with vardenafil is heart attack. Also, in rare cases, vardenafil use may cause priapism, a very painful emergency condition that can cause impotence if left untreated.^[4]

On 18 October 2007, the U.S. Food and Drug Administration (FDA) announced that a warning about possible deafness (sudden hearing loss) would be added to the drug labels of Vardenafil, and other PDE5 inhibitors.^[5]

Vardenafil, as with all PDE5 inhibitors, should not be used by men taking nitrate medications, because combining them with vardenafil might provoke potentially life-threatening hypotension (low blood pressure).

Further, Vardenafil causing lengthening of the QT interval. Therefore it should not be taken by men taking other medications that affect the QT interval (such as amiodarone).

Levitra 20mg Oral Tablet

It is available in 2.5 mg, 5 mg, 10 mg, and 20 mg doses in round orange tablets. The normal starting dose is 10 mg (roughly equivalent to 50 mg of sildenafil). Vardenafil should be taken 1 to 2 hours prior to sexual activity, with a maximum dose frequency of once per day. In some territories, such as the UK, only certain doses may be available.

Vardenafil is also available under the name Staxyn as a tablet which dissolves on the tongue rather than being swallowed in the form of a pill.

STAXYN is an oral therapy for the treatment of erectile dysfunction. This monohydrochloride salt of vardenafil is a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific PDE5.

Vardenafil HCl is designated chemically as piperazine, 1-[[3-(1,4-dihydro-5-methyl-4-oxo-7-propylimidazo[5,1f][1,2,4]triazin-2-yl)-4-ethoxyphenyl]sulfonyl]-4-ethyl-, monohydrochloride and has the following structural formula:

STAXYN (vardenafil hydrochloride) Structural Formula Illustration

Vardenafil HCl is a nearly colorless, solid substance with a molecular weight of 579.1 g/mol and a solubility of 0.11 mg/mL in water.

LEVITRA

TRIHYDRATE, HCL SALT

US2002137930A

vardenafil hydrochloride is piperazine, 1-[[3-(1,4-dihydro-5-methyl-4-oxo-7-propylimidazo[5,1-f][1,2,4]triazin-2-yl)-4-ethoxyphenyl]sulfonyl]-4-ethyl-, mono -hydrochloride and can be structurally represented by Formula I.

The monohydrochloride salt of vardenafil is a selective inhibitor of cyclic guaosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5). It is commercially available in products sold under the brand name LEVITRA formulated as 2.5 mg, 5 mg, 10 mg, 20 mg film-coated tablets.

U.S. Pat. No. 6,362,178 B1 discloses vardenafil, its related compounds and processes for their preparation. The patent describes a process in which vardenafil is obtained by recrystallization in ether in Example 19. Vardenafil produced as per Example 19 is hereinafter referred as “crystalline Form I” of vardenafil. The patent also describes processes for the preparation of its monohydrochloride and dihydrochloride salts, which are formed in a combination of ether and dichloromethane. The patent also describes a process for the preparation of vardenafil monohydrochloride trihydrate.

U.S. Patent Application Publication No. 2005/0203298 also describes a process for the preparation of vardenafil, and its monohydrochloride trihydrate.

Chemical synthesis of vardenafil has mostly been directed to the preparation of the trihydrate of monohydrochloride of vardenafil.

In WO 99/24433, sulphonamide-substituted imidazotriazinones are described as potent inhibitors of either one or more of the cyclic guanosine 3′,5′-monophosphate-metabolizing phosphodiesterases (cGMP PDEs). According to the nomenclature of Beavo and Reifsnyder (Trends in Pharmacol. Sci. 11, 150-155, 1990), these cGMP PDEs are the phosphodiesterase isoenzymes PDE-I, PDE-II and PDE-V.

According to WO 99/24433, the sulphonamide-substituted imidazotriazinones described therein are prepared from corresponding 2-ethoxyphenyl-substituted imidazotriazinones by reaction with chlorosulphonic acid and subsequent reaction with an appropriate amine, as is illustrated by the following scheme (R¹to R⁶here have the meanings indicated in WO 99/24433):

In this process, highly reactive chlorosulphonic acid has to be used as a reagent. Moreover, the imidazotriazinonesulphonyl chlorides formed as intermediates are sensitive to hydrolysis, which, in particular in the conversion of this preparation process to the industrial scale, can lead to not inconsiderable yield variations.

It was therefore the object of the present invention to make available a process for the preparation of sulphonamide-substituted imidazotriazinones in which the disadvantages of the above process known from the prior art are avoided.

This object is achieved according to the present invention by a process as in claim 1. In particular, in the process according to the invention as in claim 1 the use of chlorosulphonic acid is avoided by introduction of the sulphonic acid via a reaction with sulphuric acid and subsequent reaction with thionyl chloride. Moreover, the reaction with thionyl chloride and the subsequent reaction with an amine is carried out in a one-pot process, so that the imidazotriazinonesulphonyl chloride intermediate, which is sensitive to hydrolysis, does not need to be isolated. By means of this, yield variations on account of partial hydrolysis of this intermediate can be excluded. As a result of these advantages, the process according to the invention is much simpler to carry out on the industrial scale than the process described in WO 99/24433.

………………….

SYNTHESIS

US6362178

2-butyrylamino-propionic acid

EXAMPLE 1A 2-Butyrylaminopropionic acid

22.27 g (250 mmol) of D,L-alanine and 55.66 g (550 mmol) of triethylamine are dissolved in 250 ml of dichloromethane, and the solution is cooled to 0° C. 59.75 g (550 mmol) of trimethylsilyl chloride are added dropwise, and the solution is stirred for 1 hour at room temperature and for 1 hour at 40° C. After cooling to −10° C., 26.64 g (250 mmol) of butyryl chloride are added dropwise, and the resulting mixture is stirred for 2 hours at −10° C. and for one hour at room temperature.

With ice-cooling, 125 ml of water are added dropwise and the reaction mixture is stirred at room temperature for 15 minutes. The aqueous phase is evaporated to dryness, the residue is titrated with acetone and the mother liquor is filtered off with suction. The solvent is removed and the residue is chromatographed. The resulting product is dissolved in 3N aqueous sodium hydroxide solution and the resulting solution is evaporated to dryness. The residue is taken up in conc. HCl and once more evaporated to dryness. The residue is stirred with acetone, precipitated solid is filtered off with suction and the solvent is removed under reduced pressure. This gives 28.2 g (71%) of a viscous oil which crystallizes after some time.

200 MHz ¹H-NMR (DMSO-d6): 0.84, t, 3H; 1.22, d, 3H; 1.50, hex, 2H; 2.07, t, 2H; 4.20, quin., 1H; 8.09, d, 1H.

EXAMPLE 3A 2-Ethoxybenzonitrile

25 g (210 mmol) of 2-hydroxybenzonitrile are refluxed with 87 g of potassium carbonate and 34.3 g (314.8 mmol) of ethyl bromide in 500 ml of acetone overnight. The solid is filtered off, the solvent is removed under reduced pressure and the residue is distilled under reduced pressure. This gives 30.0 g (97%) of a colourless liquid.

200 MHz ¹H-NMR (DMSO-d6): 1.48, t, 3H; 4.15, quart., 2H; 6.99, dt, 2H; 7.51, dt, 2H.

2-ethoxybenzamidine hydrochloride

EXAMPLE 4A 2-Ethoxybenzamidine hydrochloride

21.4 g (400 mmol) of ammonium chloride are suspended in 375 ml of toluene, and the suspension is cooled to 0° C. 200 ml of a 2M solution of trimethylaluminium in hexane are added dropwise, and the mixture is stirred at room temperature until the evolution of gas has ceased. After addition of 29.44 g (200 mmol) of 2-ethoxybenzonitrile, the reaction mixture is stirred at 80° C. (bath) overnight.

With ice-cooling, the cooled reaction mixture is added to a suspension of 100 g of silica gel and 950 ml of chloroform, and the mixture is stirred at room temperature for 30 minutes. The mixture is filtered off with suction, and the filter residue is washed with the same amount of methanol. The mother liquor is concentrated, the resulting residue is stirred with a mixture of dichloromethane and methanol (9:1), the solid is filtered off with suction and the mother liquor is concentrated. This gives 30.4 g (76%) of a colourless solid.

200 MHz ¹H-NMR (DMSO-d6): 1.36, t, 3H; 4.12, quart., 2H; 7.10, t, 1H; 7.21, d, 1H; 7.52, m, 2H; 9.30, s, broad, 4H.

EXAMPLE 10A 2-(2-Ethoxy-phenyl)-5-methyl-7-propyl-3H-imidazo[5,1-f][1,2,4]triazin-4-one

7.16 g (45 mmol) of 2-butyrylamino-propionic acid and 10.67 g of pyridine are dissolved in 45 ml of THF and, after addition of a spatula tip of DMAP, heated to reflux. 12.29 g (90 mmol) of ethyl oxalyl chloride are slowly added dropwise, and the reaction mixture is refluxed for 3 hours. The mixture is poured into ice-water and extracted three times with ethyl acetate and the organic phase is dried over sodium sulphate and concentrated using a rotary evaporator. The residue is taken up in 15 ml of ethanol and refluxed with 2.15 g of sodium bicarbonate for 2.5 hours. The cooled solution is filtered.

With ice-cooling, 2.25 g (45 mmol) of hydrazine hydrate are added dropwise to a solution of 9.03 g (45 mmol) of 2-ethoxybenzamidine hydrochloride in 45 ml of ethanol, and the resulting suspension is stirred at room temperature for another 10 minutes. The ethanolic solution described above is added to this reaction mixture, and the mixture is stirred at a bath temperature of 70° C. for 4 hours. After filtration, the mixture is concentrated, the residue is partitioned between dichloromethane and water, the organic phase is dried over sodium sulphate and the solvent is removed under reduced pressure.

This residue is dissolved in 60 ml of 1,2-dichloroethane and, after addition of 7.5 ml of phosphorus oxychloride, refluxed for 2 hours. The mixture is diluted with dichloromethane and neutralized by addition of sodium bicarbonate solution and solid sodium bicarbonate. The organic phase is dried and the solvent is removed under reduced pressure. Chromatography using ethyl acetate and crystallization afford 4.00 g (28%) of a colourless solid, R_f=0.42 (dichloromethane/methanol=95:5)

200 MHz ¹H-NMR (CDCl₃): 1.02, t, 3H; 1.56, t, 3H; 1.89, hex, 2H; 2.67, s, 3H; 3.00, t, 2H; 4.26, quart., 2H; 7.05, m, 2H; 7.50, dt, 1H; 8.17, dd, 1H; 10.00, s, 1H.

EXAMPLE 15A 4-Ethoxy-3-(5-methyl-4-oxo-7-propyl-3,4-dihydro-imidazo[5,1-f][1,2,4]triazin-2-yl)-benzenesulphonyl chloride

At 0° C., 2.00 g (6.4 mmol) of 2-(2-ethoxy-phenyl)-5-methyl-7-propyl-3H-imidazo[5,1-f][1,2,4]triazin-4-one are slowly added to 3.83 ml of chlorosulphonic acid. At room temperature, the reaction mixture is stirred ovemight, and then poured into ice-water and extracted with dichloromethane. This gives 2.40 g (91%) of a colourless foam.

200 MHz ¹H-NMR (CDCl₃): 1.03, t, 3H; 1.61, t, 2H; 1.92, hex, 2H; 2.67, s, 3H; 3.10, t, 2H; 4.42, quart., 2H; 7.27, t, 1H; 8.20, dd, 1H; 8.67, d, 1H; 10.18, s, 1H.

Example 19 2-[2-Ethoxy-5-(4-ethyl-piperazine-1-sulphonyl)-phenyl]-5-methyl-7-propyl-3H-imidazo[5,1-f][1,2,4]triazin-4-one

470 mg (1.14 mmol) of 4-ethoxy-3-(5-methyl-4-oxo-7-propyl-3,4-dihydro-imidazo[5,1-f][1,2,4]triazin-2-yl)-benzenesulphonyl chloride are dissolved in 20 ml of dichloromethane and cooled to 0° C. 390 mg (3.42 mmol) of N-ethylpiperazine are added, and the reaction mixture is stirred at room temperature overnight. The mixture is diluted with dichloromethane, the organic phase is washed twice with water and dried over sodium sulphate and the solvent is removed under reduced pressure. Crystallization from ether gives 370 mg (66%) of a colourless solid.

400 MHz ¹H-NMR (CDCl₃): 1.01, t, 3H; 1.59, t, 3H; 1.88, hex, 2H; 2.42, quart., 2H; 2.56, m, 4H; 2.63, s, 3H; 3.00, t, 2H; 3.10, m, 4H; 4.33, quart., 2H, 7.17, d, 1H; 7.88, dd, 1H; 8.44, d, 1H; 9.75, s, 1H.

…………………….

US7977478

EXAMPLE 7 Preparation of the Trihydrate of Vardenafil Monohydrochloride

14 g of vardenafil hydrochloride was taken into a round bottom flask followed by the addition of 70 ml water and the pH of the reaction mass was adjusted using sodium hydroxide to 11 at 30° C. 280 ml of dichloromethane was added to the above reaction mass and the layers were separated. The organic layer was dried over sodium sulfate and the organic layer was transferred into a round bottom flask and subjected to heating for distillation at 40° C. for 1.5 hours. The solid material was transferred into a round bottom flask and 36 ml of a mixture of acetone and water in 12:1 ratio was added with stirring, then 2.2 ml of 36% aqueous hydrochloric acid was added with stirring. The reaction mass was heated to a temperature of about 45° C. and the undissolved particles were removed by filtration. The filtrate was taken into a round bottom flask and cooled to 5° C., maintained for 45 minutes at 3 to 5° C. followed by the filtration of the solid which was then subjected to suction drying and finally dried at 40° C. to yield 9.0 g of the trihydrate of vardenafil monohydrochloride.

……………………..

US20050203298

STARTING COMPOUNDS

Example I Preparation of 2-(2-ethoxyphenyl)-5-methyl-7-propyl-3H-imidazo-[5,1-f][2,4]triazin-4-oneIa) Preparation of 2-butyrylaminopropionic acid

A solution of 100 kg of D,L-alanine in aqueous sodium hydroxide solution is reacted in the cold with 119 kg of butyryl chloride. After addition of butyl acetate, the mixture is acidified with hydrochloric acid, the organic phase is separated off and the aqueous phase is re-extracted. The organic phase is dried by azeotropic distillation. The crystallizate is isolated, washed with butyl acetate and dried.

Yield: 132.6 kg (68%)

¹H-NMR: δ=0.8 (t, 3H), 1.25 (d, 3H), 1.5 (m, 2H), 2.1 (t, 2H), 4.2 (q, 1H), 8.1 (d, NH), 12.0-12.7 (s, COOH)

MS: 336 (2M+NH₄, 40), 319 (2M+H, 15), 177 (M+NH₄, 100), 160 (M+H, 20)

Ib) Preparation of 2-ethoxybenzonitrile

260 kg of thionyl chloride are added at 85-95° C. to a suspension of 250 kg of 2-ethoxybenzamide in toluene under metering control. The reaction mixture is stirred in the presence of heat. Thionyl chloride and toluene are then distilled off in vacuo. The product is employed in the subsequent stage as a crude product.

Yield: 228.5 kg (crude product)

¹H-NMR: δ=1.45 (t, 3H), 4.15 (q, 2H), 7.0 (m, 2H, phenyl), 7.5 (m, 2H, phenyl)

MS: 312 (2M+N₄, 35), 165 (M+NH₄, 100), 147 (5)

Ic) Preparation of 2-ethoxy-N-hydroxybenzamidine

111 kg of 2-ethoxybenzonitrile (crude product) from Example Ib are heated under reflux with 164 1 of triethylamine and 73 kg of hydroxylamine hydrochloride in isopropanol. The reaction mixture is treated with water and cooled. The crystallizate is isolated, washed and employed in the subsequent stage as a moist product.

Yield: 92.6 kg (moist product)

¹H-NMR: δ=1.35 (t, 3H), 4.1 (q, 2H), 5.6 (s, 2H), 6.9-7.4 (4H, phenyl), 9.4 (s, 1H, OH)

MS: 361 (2M+H, 30), 198 (M+N, 30), 181 (M+H, 100)

Id) Preparation of 2-ethoxybenzamidine hydrochloride

135 kg of 2-ethoxy-N-hydroxybenzamidine (moist product) from Example Ic are hydrogenated at 50-60° C. in acetic acid using palladium on carbon as a catalyst. For the work-up, the hydrogenation reaction is freed from the catalyst, treated with hydrochloric acid and concentrated. Residual acetic acid and water are removed by azeotropic distillation with toluene. The crystallizate is isolated and dried in vacuo.

Yield: 136.4 kg

H-NMR: 1.35 (t, 3H), 4.15 (q, 2H), 7.1-7.7 (m, 4H, phenyl), 9.1-9.4 (2×s, 3H), 10.5-10.7 (s, 1H)

MS: 329 (2M+H, 10), 165 (M+H, 100)

Ie) Preparation of 2-(2-ethoxyphenyl)-5-methyl-7-propyl-3H-imidazo[5,1-f][1,2,4]-triazin-4-one

231 kg of 2-butyrylaminopropionic acid from Example Ia are treated in tetrahydrofuran with 341 kg of pyridine, catalytic amounts of 4-N,N-dimethylaminopyridine and 392 kg of ethyl chloroxalate and stirred with heating under reflux. The reaction mixture is taken up in ethyl acetate, washed with water and the ethyl acetate phase is concentrated. The distillation residue is taken up in methanol and reacted with the following solution.

192 kg of 2-ethoxybenzamidine hydrochloride from Example Id are treated in methanol with 47.5 kg of hydrazine hydrate and the mixture is stirred at room temperature. The solution is combined with the solution of 2-butyrylamino-1-ethoxycarbonylpropenyl ethyl oxalate prepared above. The reaction mixture thus obtained is stirred with heating under reflux. Methanol is removed by distillation and replaced by acetic acid.

Option A:

138.6 kg of phosphorus oxychloride are added and stirred in the presence of heat.

Acetic acid is distilled off in vacuo. The residue is treated with water and dichloromethane or optionally methyl isobutyl ketone and rendered neutral using sodium hydroxide solution. The organic phase is concentrated, and the residue is dissolved in acetone and crystallized with cooling. The crystallizate is isolated, washed and dried.

Option B:

At least 190 kg of acetyl chloride are added and stirred in the presence of heat. Acetic acid is distilled off in vacuo. The distillation residue is treated with acetone and water, and the product is crystallized by rendering neutral with sodium hydroxide solution. The product is isolated, washed and dried.

Yield: 90-160 kg

¹H-NMR: δ=1.0 (t, 3H), 1.6 (t, 3H), 1.9 (m, 2H), 2.8 (s, 3H), 3.3 (t, 2H), 4.3 (q, 2H), 7.0-8.2 (Ar, 4H), 10.3 (CONH, 1H)

MS: 313 (M+H, 100), 149 (25), 151 (40), 121 (15)

HPLC: Kromasil C-18 phase, neutral phosphate buffer, acetonitrile, 233 nm, linear gradient of 30% acetonitrile ->80% acetonitrile (30 min.): 99 area % (R_t19.1)

PREPARATION EXAMPLES Example 1a 4-ethoxy-3-(5-methyl-4-oxo-7-propyl-3,4-dihydroimidazo[5,1-fl-][1,2,4]triazin-2-yl)benzenesulphonic acid

194 kg of 2-(2-ethoxyphenyl)-5-methyl-7-propyl-3H-imidazo[5,1-f][1,2,4]triazin-4-one from Example Ie are reacted with 504 kg of concentrated sulphuric acid. The reaction mixture is added to water, cooled, and the crystallizate is isolated and dried in vacuo.

Yield: 195.2 kg

¹H-NMR: δ=0.95 (t, 3H), 1.3 (t, 3H), 1.8 (m, 2H), 2.6 (s, 3H), 3.05 (t, 2H), 4.1 (q, 2H), 7.15 (Ar, 1H), 7.75 (m, 2H), 12.3 (SO₂OH)

MS: 393 (M+H, 100), 365 (25), 151 (40)

HPLC: X-Terra C-18 phase, aqueous phosphoric acid, acetonitrile, 242 nm, linear gradient of 10% acetonitrile ->90% acetonitrile (20 min.):

98 area % (R, 9.2)

Example 1b) 2-[2-ethoxy-5-(4-ethlylpiperazin-1-sulphonyl)phenyl]-5-methyl-7-propyl-3H-imidazo[5,1-f][1,2,4]triazin-4-one

22.5 kg of 4-ethoxy-3-(5-methyl-4-oxo-7-propyl-3,4-dihydro-imidazo[5,1-f][1,2,4]-triazin-2-yl)benzenesulphonic acid from Example 1a are reacted with 74 kg of thionyl chloride and catalytic amounts of dimethylformamide until the evolution of gas has ended. Xylene is repeatedly added to the reaction mixture and thionyl chloride is distilled off. 15.1 kg of N-ethylpiperazine are added to the suspension and it is stirred. After the addition of water, it is adjusted to pH 1 using hydrochloric acid, and the phases are separated. The aqueous phase is treated with acetone and rendered neutral by addition of sodium hydroxide solution. The mixture is cooled, and the crystallizate is isolated, washed and dried in vacuo.

Yield: 26.1 kg

¹H-NMR: δ=1.0 (2×t, 6H), 1.6 (t, 3H), 1.9 (m, 2H), 2.45 (q, 2H), 2.55 (m, 4H), 2.65 (s, 3H), 3.0 (t, 2H), 3.1 (m, 4H), 4.35 (q, 2H), 7.15 (Ar, 1H), 7.9 (Ar, 1H), 8.4 (Ar, 1H), 9.8 (CONH)

MS: 489 (M+H, 100), 345 (10), 313, (10), 285 (10), 113 (20)

HPLC: X-Terra C-18 phase, neutral phosphate buffer, acetonitrile, 242 nm, linear gradient of 20% acetonitrile ->75% acetonitrile (20 min.): 98 area % (R_t16.3)

1 c) 2-[2-ethoxy-5-(4-ethylpiperazin-1-sulphonyl)phenyl]-5-methyl-7-propyl-3H-imidazo[5,1-fl][1,2,4]triazin-4-one hydrochloride trihydrate

22.5 kg of 2-[2-ethoxy-5-(4-ethylpiperazin-1-sulphonyl)phenyl]-5-methyl-7-propyl-3H-imidazo[5,1-f][1,2,4]triazin-4-one from Example 1b are dissolved in 5.1 kg of concentrated hydrochloric acid and acetone/water (12:1 v/v) in the presence of heat. The clear solution is filtered hot and crystallized by cooling and seeding. The crystallizate is isolated, washed and dried in vacuo at about 30° C. and about 300 mbar.

Yield: 25.4 kg

M.p. (DSC): 192° C.

HPLC: X-Terra C-18 phase, neutral phosphate buffer, acetonitrile, 242 nm, linear gradient of 20% acetonitrile ->75% acetonitrile (20 min.): 99 area % (R_t16.3)

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WO2004006894A1 *	Jul 3, 2003	Jan 22, 2004	Bayer Healthcare Ag	Medicaments containing vardenafil hydrochloride trihydrate

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FDA approves Praxbind, Idarucizumab the first reversal agent for the anticoagulant Pradaxa

October 17, 2015 1:05 am / Leave a comment

FDA approves Praxbind, the first reversal agent for the anticoagulant Pradaxa

10/16/2015 01:07 PM EDT

The FDA has granted accelerated approval to Praxbind (idarucizumab) for use in patients who are taking the anticoagulant Pradaxa (dabigatran) during emergency situations when there is a need to reverse Pradaxa’s blood-thinning effects.

October 16, 2015

Release

The U.S. Food and Drug Administration today granted accelerated approval to Praxbind (idarucizumab) for use in patients who are taking the anticoagulant Pradaxa (dabigatran) during emergency situations when there is a need to reverse Pradaxa’s blood-thinning effects.

“The anticoagulant effects of Pradaxa are important and life-saving for some patients, but there are situations where reversal of the drug’s effects is medically necessary,” said Richard Pazdur, M.D., director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research. “Today’s approval offers the medical community an important tool for managing patients taking Pradaxa in emergency or life-threatening situations when bleeding can’t be controlled.”

The FDA approved Pradaxa in 2010 to prevent stroke and systemic blood clots in patients with atrial fibrillation, as well as for the treatment and prevention of deep venous thrombosis and pulmonary embolism. Praxbind is the first reversal agent approved specifically for Pradaxa and works by binding to the drug compound to neutralize its effect. Praxbind solution is for intravenous injection.

The safety and effectiveness of Praxbind were studied in three trials involving a total of 283 healthy volunteers taking Pradaxa (i.e., people who did not require an anticoagulant). In the healthy volunteers who were given Praxbind, there was an immediate reduction in the amount of Pradaxa in participants’ blood (measured as unbound dabigatran plasma concentration) that lasted for a period of at least 24 hours. In this study, the most common side effect from use of Praxbind was headache.

Another trial included 123 patients taking Pradaxa who received Praxbind due to uncontrolled bleeding or because they required emergency surgery. In this ongoing trial, based on laboratory testing, the anticoagulant effect of Pradaxa was fully reversed in 89 percent of patients within four hours of receiving Praxbind. In this patient trial, the most common side effects were low potassium (hypokalemia), confusion, constipation, fever and pneumonia.

Reversing the effect of Pradaxa exposes patients to the risk of blood clots and stroke from their underlying disease (such as atrial fibrillation). The Praxbind labeling recommends patients resume their anticoagulant therapy as soon as medically appropriate, as determined by their health care provider.

Praxbind is approved under the FDA’s accelerated approval program, which allows the agency to approve drugs for serious conditions that fill an unmet medical need based on an effect on a surrogate or an intermediate clinical endpoint that is reasonably likely to predict a clinical benefit to patients. The program is designed to provide patients with earlier access to promising new drugs, but the company will be required to submit additional clinical information after approval to confirm the drug’s clinical benefit.

Praxbind and Pradaxa are both marketed by Boehringer Ingelheim of Ridgefield, Connecticut.

Etelcalcetide, AMG 416, KAI-4169, velcalcetide

October 16, 2015 7:45 am / 4 Comments on Etelcalcetide, AMG 416, KAI-4169, velcalcetide

H-L-Cys-OH

S— S

Ac-D-Cys-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH₂

AMG 416 IS (Ac-D-Cys(L-Cys-OH)-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH₂)

Etelcalcetide (AMG 416, KAI-4169, velcalcetide)

The main chain has 7 amino acids, all in the D-configuration. The side-chain cysteine residue is in the L-configuration. The molecular formula of AMG 416 (free base) is C38H73N21O10S2, and has a calculated average molecular mass of 1048.3 Da.

D-Argininamide, N-acetyl-D-cysteinyl-D-alanyl-D-arginyl-D-arginyl-D-arginyl-D-alanyl-, disulfide with L-cysteine, hydrochloride (1:?)

N-Acetyl-D-cysteinyl-D-alanyl-D-arginyl-D-arginyl-D-arginyl-D-alanyl-D-argininamide disulfide with L-cysteine hydrochloride

http://www.amgenpipeline.com/pipeline/

WO 2011/014707. , the compound may be represented as follows:

H-L-Cys-OH

S— S

Ac-D-Cys-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH₂

The main chain has 7 amino acids, all in the D-configuration and the side-chain cysteine residue is in the L-configuration. The amino terminal is acetylated and the carboxyl-terminal is amidated. This compound (“AMG-416”) has utility for the treatment of secondary hyperparathyroidism (SHPT) in hemodialysis patients. A liquid formulation comprising AMG-416 may be administered to a subject intravenously. The hydrochloride salt of AMG-416 may be represented as follows:

H-L-Cys-OH

S— S

Ac-D-Cys-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH₂ · x(HCl)

Therapeutic peptides pose a number of challenges with respect to their formulation. Peptides in general, and particularly those that contain a disulfide bond, typically have only moderate or poor stability in aqueous solution. Peptides are prone to amide bond hydrolysis at both high and low pH.

Disulfide bonds can be unstable even under quite mild conditions (close to neutral pH). In addition, disulfide containing peptides that are not cyclic are particularly prone to dimer formation. Accordingly, therapeutic peptides are often provided in lyophilized form, as a dry powder or cake, for later reconstitution.

A lyophilized formulation of a therapeutic peptide has the advantage of providing stability for long periods of time, but is less convenient to use as it requires the addition of one or more diluents and there is the potential risk for errors due to the use of an improper type or amount of diluent, as well as risk of contamination. In addition, the lyophilization process is time consuming and costly.

H-L-Cys-OH

S— S

Ac-D-Cys-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH₂

Generic Name:Etelcalcetide
Synonym:KAI-4169
CAS Number:1262780-97-1
N-acetyl-D-cysteinyl-S-(L-cysteine disulfide)-D-alanyl-D-arginyl-D-arginyl-D-arginyl-D-alanyl-D-argininamide
Mechanism of Action:Activates calcium sensing receptor on parathyroid glands reducing PTH synthesis and secretion
Indication: secondary hyperparathyroidism associated with chronic kidney disease
Development Stage: Phase III
Developer:KAI Pharmaceuticals/Amgen Inc.

H-L-Cys-OH

S— S

Ac-D-Cys-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH₂ · x(HCl)

HYDROCHLORIDE

Generic Name:Etelcalcetide Hydrochloride
AMG 416, KAI-4169, previously also known as velcalcetide hydrochloride
CAS :1334237-71-6
Chemical Name:N-acetyl-D-cysteinyl-D-alanyl-D-arginyl-D-arginyl-D-arginyl-D-alanyl-D-argininamide disulfide with L-cysteine hydrochloride
Mechanism of Action:Activates calcium sensing receptor on parathyroid glands reducing PTH synthesis and secretion
Indication: secondary hyperparathyroidism associated with chronic kidney disease
Development Stage: Phase III
Developer:KAI Pharmaceuticals/Amgen Inc.

Method for preparing etelcalcetide and its salts, particularly hydrochloride. See WO2014210489, for a prior filing claiming stable liquid formulation of etelcalcetide. Amgen, following its acquisition of KAI Pharmaceuticals, and Japanese licensee Ono Pharmaceuticals are developing etelcalcetide, a long-acting iv isozyme-selective peptide-based protein kinase C epsilon inhibitor and agonist of the calcium-sensing receptor, for treating secondary hyperparathyroidism (SHPT) in patients with end-stage renal disease receiving dialysis.

In August 2015, an NDA was submitted seeking approval of the drug for SHPT in patients with chronic kidney disease (CKD) on hemodialysis (HD) in the US.

In September 2015, Amgen filed an MAA under the centralized procedure in the EU for the approval of etelcalcetide for treating SHPT in patients with CKD on HD therapy.

KAI is also investigating a transdermal patch formulation of the drug for treating primary HPT.

AMG 416

Secondary hyperparathyroidism in patients with chronic kidney disease receiving dialysis

AMG 416 is a peptide agonist of the human cell surface calcium-sensing receptor (CaSR). It is being investigated as a treatment for secondary hyperparathyroidism in patients with chronic kidney disease receiving dialysis.

Etelcalcetide is a novel calcimimetic agent that suppresses the secretion of parathyroid hormone and is in clinical development for the treatment of SHPT in patients with CKD on hemodialysis. Etelcalcetide is administered intravenously three times per week at the end of each dialysis session. It acts by binding to and activating the calcium-sensing receptor on the parathyroid gland, thereby causing decreases in parathyroid hormone (PTH). Sustained elevations in PTH are known to be associated with significant clinical consequences for patients with CKD.

The submission includes data from three Phase 3 studies, all of which met the primary endpoints, including two pooled placebo-controlled trials in more than 1,000 patients and a head-to-head study evaluating etelcalcetide compared with cinacalcet.

About Secondary HyperparathyroidismSHPT is a common and serious condition that is often progressive among patients with CKD, and it affects many of the approximately two million people throughout the world who are receiving dialysis, including 450,000 people in the U.S. The disorder develops early in the course of CKD and usually manifests as increased levels of PTH as a result of increased production from the parathyroid glands (four small glands in the neck). Patients with end stage renal disease who require maintenance dialysis often have substantial elevations of PTH that are commonly associated with abnormal calcium and phosphorus levels and an increased risk of significant clinical consequences.

About Etelcalcetide (AMG 416)Etelcalcetide is a novel calcimimetic agent in clinical development for the treatment of SHPT in CKD patients on hemodialysis that is administered intravenously at the end of the dialysis session. Etelcalcetide binds to and activates the calcium-sensing receptor on the parathyroid gland, thereby decreasing PTH levels.

About Sensipar^® (cinacalcet)Sensipar^® (cinacalcet) is the first oral calcimimetic agent approved by the FDA for the treatment of SHPT in adult patients with CKD on dialysis. Sensipar is not indicated for use in adult patients with CKD who are not on dialysis because of an increased risk of hypocalcemia. The therapy is also approved in the U.S. for treatment of hypercalcemia in adult patients with parathyroid carcinoma and hypercalcemia in adult patients with primary HPT for whom parathyroidectomy would be indicated on the basis of serum calcium levels, but who are unable to undergo parathyroidectomy. Sensipar binds to the calcium-sensing receptor, resulting in a drop in PTH levels by inhibiting PTH synthesis and secretion. In addition, the reductions in PTH lower serum calcium and phosphorus levels.

Milestones

25 Aug 2015 Preregistration for Secondary hyperparathyroidism in USA (IV)
29 May 2015 Pooled analysis efficacy and adverse events data from two phase III trials in secondary hyperparathyroidism released by Amgen
21 Apr 2015 Amgen plans to submit Biological License Application to USFDA and Marketing Authorisation Application to EMA for Secondary hyperparathyroidism

PATENT

WO2011014707

http://www.google.com/patents/WO2011014707A2?cl=en

PATENT

WO 2015154031

https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2015154031&recNum=1&maxRec=&office=&prevFilter=&sortOption=&queryString=&tab=PCTDescription

The hydrochloride salt of AMG 416 has the chemical structure:

H-L-Cys-OH

s— s

Ac-D-Cys-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH₂ · x(HCl)

(SEQ ID NO:l)

AMG 416 and a method for its preparation are described in International Pat. Publication No. WO 2011/014707, which is incorporated herein by reference for any purpose. As described in International Pat. Publication No. WO 2011/014707, AMG 416 may be assembled by solid-phase synthesis from the corresponding Fmoc-protected D-amino acids. After cleavage from the resin, the material may be treated with Boc-L-Cys(NPyS)-OH to form the disulfide bond. The Boc group may then be removed with trifluoroacetate (TFA) and the resulting product purified by reverse-phase high pressure liquid chromatography (HPLC) and isolated as the TFA salt form by lyophilization. The TFA salt can be converted to a pharmaceutically acceptable salt by carrying out a subsequent salt exchange procedure. Such procedures are well known in the art and include, e.g., an ion exchange technique, optionally followed by purification of the resultant product (for example by reverse phase liquid chromatography or reverse osmosis).

There is a need for an efficient method of producing AMG 416, or a pharmaceutically acceptable salt thereof (e.g., AMG 416 HC1), and particularly one appropriate for commercial scale manufacturing.

In a first aspect, provided is a method for preparing AMG 416, the method comprising: providing a resin-bound peptide having a structure selected from the group consisting of Fmoc-D-Cys(Trt)-D-Ala-D- Arg(Pbf)-D-Arg(Pbf)-D-Arg(Pbf)-D-Ala-D-Arg(Pbf)-[Resin] (SEQ ID NO:2) and Ac-D-Cys(Trt)-D-Ala-D- Arg(Pbf)-D-Arg(Pbf)-D-Arg(Pbf)-D-Ala-D-Arg(Pbf)-[Resin] (SEQ ID NO:3); cleaving the peptide from the solid support; and activating the side chain of the D-Cys residue of the cleaved peptide.

In a second aspect, provided is a method for preparing AMG 416, the method comprising: providing a peptide having a structure of Ac-D-Cys(SPy)-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH₂ (SEQ ID NO:4); and contacting the peptide with L-Cys to produce a conjugated product.

In yet a third aspect provided is a method for preparing AMG 416, the method comprising: providing a resin-bound peptide having a structure selected from the group consisting of Fmoc-D-Cys(Trt)-D-Ala-D-Arg(Pbf)-D-Arg(Pbf)-D-Arg(Pbf)-D-Ala-D-Arg(Pbf)-[Resin] (SEQ ID NO:2) and Ac-D-Cys(Trt)-D-Ala-D-Arg(Pbf)-D-Arg(Pbf)-D-Arg(Pbf)-D-Ala-D-Arg(Pbf)-[Resin] (SEQ ID NO:3); cleaving the peptide from the solid support, i.e., to provide an unsupported peptide, and activating the side chain of the D-Cys residue of the unsupported peptide to generate an AMG 416 SPy intermediate (where SPy is 2-pyridinesulfenyl or S-Pyr), dissolving the AMG 416 SPy intermediate in an aqueous 0.1% TFA (trifluoroacetic acid solution), and purifying the AMG 416 SPy derivative by HPLC.

The term “AMG 416”, also known as etelcalcetide, formerly known as velcalcetide or KAI-4169, refers to a compound having the chemical name: N-acetyl-D-cysteinyl-D-alanyl-D-arginyl-D-arginyl-D-arginyl-D-alanyl-D-arginamide disulfide with L-cysteine, which has the following structural formula:

H-L-Cys-OH

s— s

Ac-D-Cys-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH₂

Reference to AMG 416, or to any compound or AMG 416 fragment, intermediate, or precursor as described herein, is intended to encompass neutral, uncharged forms thereof, as well as pharmaceutically acceptable salts, hydrates and solvates thereof.

The terms “AMG 416 hydrochloride” and “AMG 416 HC1” are interchangeable and refer to a hydrochloride salt form of AMG 416 having the following structural formula:

H-L-Cys-OH

s— s

Ac-D-Cys-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH₂ · xHCl

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the chemical structure of AMG 416 (Ac-D-Cys(L-Cys-OH)-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH₂) (SEQ ID NO: l).

FIG. 2 shows the chemical structure of Rink Amide AM resin and Ac-D-Cys(Trt)- D-Ala-D-Arg(Pbf)-D-Arg(Pbf)-D-Arg(Pbf)-D-Ala-D-Arg(Pbf)-Resin (SEQ ID NO:3).

FIG. 3 shows a reaction scheme in which the SPy intermediate product (Ac-D-Cys(SPy)-D-Ala-D-Arg-D-Arg-D-Arg-D-Ala-D-Arg-NH₂) (SEQ ID NO:4) is formed from the peptidyl-resin (Ac-D-Cys(Trt)-D-Ala-D-Arg(Pbf)-D-Arg(Pbf)-D-Arg(Pbf)-D-Ala-D-Arg(Pbf)-NH-Resin) (SEQ ID NO:3).

FIG. 4 shows a reaction scheme in which a TFA salt of AMG 416 is formed from the SPy intermediate (AA^1_7(SPy)).

FIG. 5 shows a reaction scheme in which the HC1 salt of AMG 416 is formed from the TFA salt of AMG 416.

FIG. 6 shows a reaction scheme in which Boc-D-Arg(Pbf)-OH is formed from Boc-D-Arg-OH.

FIG. 7 shows a reaction scheme in which D-Arg(Pbf)-OH is formed from Boc-D-Arg(Pbf)-OH.

EXAMPLE 5

Purification of the SPy Intermediate and Production of AMG 416 HC1

An alternative method for preparation of AMG 416 HC1 salt is described here. As described in Example 2 above, the SPy intermediate product was dried at 20°C under full vacuum after cleavage from the resin, precipitation and filtration. The precipitate was then dissolved in a 0.1% TFA aqueous solution and loaded onto a C-18 column for HPLC purification. The column was run at <60 bar and the solution temperature was 15-25 °C throughout. The eluents were 0.1% TFA in acetonitrile and 0.1% TFA in water. The fractions were stored at 5°C, they were sampled and then fractions were pooled. The combined pools from two runs were diluted and a concentration/purification run was performed using the same HPLC column to decrease the total volume and remove additional impurities. The fractions were stored at 5°C.

The fractions containing the AMG 416 SPy intermediate were subjected to azeotropic distillation to change the solvent from the 0.1% TFA to a 15% water in IPA solution, charging with IPA as needed. To the resultant AMG 416 SPy intermediate in IPA solution was then added L-Cysteine 1.15 eq and the reaction was allowed to proceed at room temperature for conjugation to occur and to form the AMG 416 TFA salt as described above in Example 4. The AMG 416 TFA solution was added to a solution of 12M aqueous HC1, 0.27 L/kg and IPA 49.4 L/kg over 3 hours via subsurface addition, resulting in direct precipitation of the AMG 416 4.5 HC1 salt. The batch was aged for 3 hours and sampled for analysis.

The material was filtered and slurry washed with 96 wt% IPA, 10 L/kg. The cake was then re-slurried for 4 hours in 10 L/kg of 96% wt% IPA. The material was filtered and further slurry washed with 96% IPA, 10 L/kg and then IPA 10 L/kg. The material was dried under full vacuum at 25°C. The dry cake was dissolved in water 8 L/kg and the batch was concentrated via distillation to remove residual IPA and achieve the desired concentration. The solution temperature was kept below 25 °C throughout the distillation.

PATENT

WO2014210489

SEE

https://patentscope.wipo.int/search/en/detail.jsf;jsessionid=2A32CFD9CE075079399E9DD298899C9D.wapp2nC?docId=WO2014210489&recNum=1&maxRec=&office=&prevFilter=&sortOption=&queryString=&tab=PCTDescription

EXAMPLE 1

Solubility of AMG 416 in Succinate Buffered Saline

In this study, the solubility of AMG 416 in succinate buffered-saline was investigated. AMG 416 HC1 (103 mg powder, 80 mg peptide) was dissolved in 200 iL of sodium succinate buffered saline (25 mM succinate, 0.9% saline, pH 4.5). After briefly vortexing, a clear solution was obtained with a nominal concentration of 400 mg/mL. Because expansion of the solution volume was not determined, the solubility of AMG 416 can be conservatively stated as at least 200 mg/mL. Although the maximal solubility was not determined in this experiment, AMG 416 is soluble in pH 4.5 succinate buffered saline to concentrations of at least 200 mg/mL.

REFERENCES

KAI-4169, a novel calcium sensing receptor agonist, decreases serum iPTH, FGF-23 and improves serum bone markers in a phase 2 study in hemodialysis subjects with chronic kidney disease-mineral and bone disorder
49th Congr Eur Renal Assoc – Eur Dialysis Transpl Assoc (May 24-27, Paris) 2012, Abst SAO054

KAI-4169, a novel peptide agonist of the calcium sensing receptor, attenuates PTH and soft tissue calcification and restores parathyroid gland VDR levels in uremic rats
49th Congr Eur Renal Assoc – Eur Dialysis Transpl Assoc (May 24-27, Paris) 2012, Abst SAO014

Long term safety and efficacy of velcalcetide (AMG 416), a calcium-sensing receptor (CaSR) agonist, for the treatment of secondary hyperparathyroidism (SHPT) in hemodialysis (HD) patients
Kidney Week (November 5-10, Atlanta, GA) 2013, Abst SA-PO575

Preclinical PK and PD relationship for KAI-4169, a novel calcimimetic
93rd Annu Meet Endo Soc (June 4-7, Boston) 2011, Abst P1-198

KAI-4169, a novel calcimimetic for the treatment of secondary hyperparathyroidism
93rd Annu Meet Endo Soc (June 4-7, Boston) 2011, Abst P2-98

Characterization of KAI-4169, a novel peptide for the treatment of chronic kidney disease – Mineral and bone disorder, in a phase I study in healthy males
44th Annu Meet Am Soc Nephrol (ASN) (November 8-13, Philadelphia) 2011, Abst FR-PO1238

WO2011014707A2	Jul 29, 2010	Feb 3, 2011	Kai Pharmaceuticals, Inc.	Therapeutic agents for reducing parathyroid hormone levels

//////////////Etelcalcetide, AMG 416, KAI-4169, velcalcetide, peptide drugs

Multistep Flow Synthesis of 5-Amino-2-aryl-2H-[1,2,3]-triazole-4- carbonitrilesultistep Flow Synthesis of 5-Amino-2-aryl-2H-[1,2,3]-triazole-4- carbonitriles

October 15, 2015 8:09 am / Leave a comment

Using the Uniqsis FlowSyn flow chemistry system researchers from the UCB Biopharma. Belgium have developed a flow synthesis of 2-substituted 1,2,3-triazoles that demonstrates improvements over the conventional batch route.

The route involves the diazotisation of anilines and condensation with malononitrile followed by the nucleophilic addition of ammonia or an alkylamine and finally a novel copper catalysed cyclisation. The intermediate azide was generated and consumed in situ which enabled safe scale up under the flow-through conditions employed.

J. Jacq, P. Pasau, Chem Eur. J., 2014, 20, (38), 12223.

DOI: 10.1002/chem.201402074

Multistep Flow Synthesis of 5-Amino-2-aryl-2H-[1,2,3]-triazole-4-carbonitriles

Authors, Dr. Jérôme Jacq, Dr. Patrick Pasau

Corresponding author

E-mail address: patrick.pasau@ucb.com

UCB Biopharma, Avenue de l’Industrie, 1420 Braine l’Alleud (Belgium)

UCB Biopharma, Avenue de l’Industrie, 1420 Braine l’Alleud (Belgium)===

1,2,3-Triazole has become one of the most important heterocycles in contemporary medicinal chemistry. The development of the copper-catalyzed Huisgen cycloaddition has allowed the efficient synthesis of 1-substituted 1,2,3-triazoles. However, only a few methods are available for the selective preparation of 2-substituted 1,2,3-triazole isomers. In this context, we decided to develop an efficient flow synthesis for the preparation of various 2-aryl-1,2,3-triazoles. Our strategy involves a three-step synthesis under continuous-flow conditions that starts from the diazotization of anilines and subsequent reaction with malononitrile, followed by nucleophilic addition of amines, and finally employs a catalytic copper(II) cyclization. Potential safety hazards associated with the formation of reactive diazonium species have been addressed by inline quenching. The use of flow equipment allows reliable scale up processes with precise control of the reaction conditions. Synthesis of 2-substituted 1,2,3-triazoles has been achieved in good yields with excellent selectivities, thus providing a wide range of 1,2,3-triazoles.http://onlinelibrary.wiley.com/wol1/doi/10.1002/chem.201402074/full

http://onlinelibrary.wiley.com/store/10.1002/chem.201402074/asset/supinfo/chem_201402074_sm_miscellaneous_information.pdf?v=1&s=77c885224607254b0d594d6cd190e655dd4ac7ee

1H/13c NMR OF 1a

UCB Biopharma, Belgium

Uniqsis FlowSyn

Uniqsis Ltd

Telephone

Email

Map of cambridgeshire

Halifax survey names South Cambridgeshire as best place to live in rural Britain

///////////FLOW SYNTHESIS, UCB Biopharma, Belgium, Uniqsis FlowSyn

Monoclonal Antibody Therapy: What is in the name or clear description?

October 15, 2015 4:23 am / Leave a comment

Leaders in Pharmaceutical Business Intelligence Group, LLC, Doing Business As LPBI Group, Newton, MA

Monoclonal Antibody Therapy: What is in the name or clear description?

Curator: Demet Sag, PhD, CRA, GCP

What is in the name?

Nomenclature is important part of the scientific community so we can stay on the same page in all kinds of communications for clarity. Therefore, a defined nomenclature scheme for assigning generic, or nonproprietary, names to monoclonal antibody drugs is used by the World Health Organization’s International Nonproprietary Names (INN) and the United States Adopted Names (USAN). In general, word stems are used to identify classes of drugs, in most cases placed at the end of the word.

Knowing what Antibody relies on understanding of immune response system so that one can modify the cells, choose correct biomarkers from the primary pathways (like Notch, WNT etc), know signaling from outside to inside (like GPCRs, MAPKs, nuclear transcription receptors), personalized gene make up (genomics) and key gene regulation mechanisms. Thus…

View original post 2,927 more words

Finally published: new Annex 16 on QP Certification and Batch Release

October 15, 2015 3:20 am / 1 Comment on Finally published: new Annex 16 on QP Certification and Batch Release

Finally published: new Annex 16 on QP Certification and Batch Release

The European Commission finally has published the new EU-GMP Guideline Annex 16 “Certification by a Qualified Person and Batch Release“.

The European Commission has published the final version of the revised EU-GMP Guideline Annex 16 “Certification by a Qualified Person and Batch Release”. Deadline for coming into operation is 15 April 2016.

As one important topic, it has been pointed out that the major task of a Qualified Person (QP) is the certification of a batch for its release. In this context, the QP must personally ensure the responsibilities listed in chapter 1.6 are fulfilled. In chapter 1.7 a lot of additional responsibilities are listed which need to be secured by the QP. The work can be delegated and the QP can rely on the respective Quality Management Systems. However “the QP should have on-going assurance that this reliance is well founded” (1.7). Amongst these twenty-one tasks are for example:

Starting materials comply and the supply chain is secured, including GMP assessments by third parties
The necessary audits have been performed and the audit reports are available
Manufacturing and testing performance are compliant with the MA
Manufacturing and testing processes are validated
Changes have been evaluated and investigations completed

It is important to mention in this context that “the ultimate responsibility for the performance of an authorised medicinal product over its lifetime; its safety, quality and efficacy lies with the marketing authorisation holder (MAH). However “the QP is responsible for ensuring that each individual batch has been manufactured and checked in compliance with laws in force (…), in accordance with the requirements of the marketing authorisation (MA) and with Good Manufacturing Practice (GMP)” (see General Principles).

In the case that the QP has to rely on the correct functioning of the quality management system of other sites, the QP “should ensure that a written final assessment and approval of third party audit reports has been made”. The QP should also “be aware of the outcome of an audit with critical impact on the product quality before certifying the relevant batches.”

Another important section clarifies the role of the QP when it comes to deviations, implementing main features of the EMA Position Paper on QP Discretion (which was issued in February 2006 and updated January 2008). Chapter 3 of the draft describes the “handling of unexpected deviations”. A batch with an unexpected deviation from details contained within the Marketing Authorisation and/or GMP may be certified if a risk assessment is performed, evaluating a “potential impact of the deviation on quality, safety or efficacy of the batch(es) concerned and conclusion that the impact is negligible.” Depending on the outcome of the investigation and the root cause, the submission of a variation to the MA for the continued manufacture of the product might be required.

During the consultation phase, stakeholders expressed their concerns regarding the sampling of imported products. Now the new annex is clear on this: “Samples may either be taken after arrival in the EU, or be taken at the manufacturing site in the third country in accordance with a technically justified approach which is documented within the company’s quality system. (…) Any samples taken outside the EU should be shipped under equivalent transport conditions as the batch that they represent.”

The new annex is rather short on other importation requirements. These requirements will probably be defined in the new Annex 21

http://www.gmp-compliance.org/enews_05058_Finally-published-new-Annex-16-on-QP-Certification-and-Batch-Release_9336,15099,15138,Z-QAMPP_n.html

.////////////published, new Annex 16, QP Certification and Batch Release

The new APIC Guidance on Handling of Insoluble Matter and Foreign Particles in the Manufacture of Active Pharmaceutical Ingredients

October 15, 2015 3:13 am / 1 Comment on The new APIC Guidance on Handling of Insoluble Matter and Foreign Particles in the Manufacture of Active Pharmaceutical Ingredients

The new APIC Guidance on Handling of Insoluble Matter and Foreign Particles in the Manufacture of Active Pharmaceutical Ingredients

The occurrence of foreign particles in the manufacture of active pharmaceutical ingredients is always undesirable. For the responsible QA departments it involves an increased effort as concerns the search for the root causes and for CAPA measures. A new APIC Guidance offers concrete recommendations for the GMP compliant handling of foreign particles in APIs, intermediates and raw materials.

Foreign particles in APIs or medicinal preparations are undesirable and sometimes lead to a recall of the batches concerned. Depending on the type of particles their presence in active pharmaceutical ingredients may be harmless; in many cases they are inevitable. In any case the manufacturer must find an adequate way how to handle those impurities visible to the human eye. The search for a guideline or another official document in the relevant regulations is in vain. Visible particles or fibres are only mentioned in the USP chapter <790>, in chapter 2.9.20 of the European Pharmacopoeia as well as in the United States Food, Drug and Cosmetic Act (FD&C Act).

In order to remedy this lack of guidance or recommendations a group of experts within APIC has drawn up a guidance on the handling of foreign particles. This “Guidance on Handling of insoluble Matter and Foreign Particles in APIs” describes in detail

the types of particles which can often occur during the manufacture of APIs, API intermediates and raw materials (including packaging materials),
suitable measures to minimize the presence of particles or to remove them,
how to determine them analytically
how to identify the source and to carry out subsequent CAPA measures and an adequate risk management.

This APIC guidance offers valuable assistance for all API manufacturers that are confronted with the problem of the occurrence of foreign particles in their products, intermediates or raw materials. The implementation of the very concrete and practicable recommendations in this guidance offers also valuable supporting arguments for GMP inspections or audits and can help to avoid unpleasant surprises.

http://www.gmp-compliance.org/enews_05022_The-new-APIC-Guidance-on-Handling-of-Insoluble-Matter-and-Foreign-Particles-in-the-Manufacture-of-Active-Pharmaceutical-Ingredients_9300,S-WKS_n.html

///////APIC Guidance, Handling of Insoluble Matter and Foreign Particles, Manufacture, Active Pharmaceutical Ingredients

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Synthesis of Impurities of Pramipexole Dihydrochloride

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2-Pyrimidinamine, N-(5-((4-ethyl-1-piperazinyl)methyl)-2-pyridinyl)-5-fluoro-4-(4-fluoro-2-methyl-1-(1-methylethyl)-1H-benzimidazol-6-yl)

Treatment of Advanced Cancer

SYNTHESIS US20100160340

Synthesis….http://www.joygooo.com/news_110.htm?pageNum=21

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Etelcalcetide (AMG 416, KAI-4169, velcalcetide)

D-Argininamide, N-acetyl-D-cysteinyl-D-alanyl-D-arginyl-D-arginyl-D-arginyl-D-alanyl-, disulfide with L-cysteine, hydrochloride (1:?)

N-Acetyl-D-cysteinyl-D-alanyl-D-arginyl-D-arginyl-D-arginyl-D-alanyl-D-argininamide disulfide with L-cysteine hydrochloride

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Multistep Flow Synthesis of 5-Amino-2-aryl-2H-[1,2,3]-triazole-4-carbonitriles

Authors, Dr. Jérôme Jacq, Dr. Patrick Pasau

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Monoclonal Antibody Therapy: What is in the name or clear description?

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US20100160340