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ORGANIC SPECTROSCOPY

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DR ANTHONY MELVIN CRASTO Ph.D

DR ANTHONY MELVIN CRASTO Ph.D

DR ANTHONY MELVIN CRASTO, Born in Mumbai in 1964 and graduated from Mumbai University, Completed his Ph.D from ICT, 1991,Matunga, Mumbai, India, in Organic Chemistry, The thesis topic was Synthesis of Novel Pyrethroid Analogues, Currently he is working with GLENMARK PHARMACEUTICALS LTD, Research Centre as Principal Scientist, Process Research (bulk actives) at Mahape, Navi Mumbai, India. Total Industry exp 29 plus yrs, Prior to joining Glenmark, he has worked with major multinationals like Hoechst Marion Roussel, now Sanofi, Searle India Ltd, now RPG lifesciences, etc. He has worked with notable scientists like Dr K Nagarajan, Dr Ralph Stapel, Prof S Seshadri etc, He did custom synthesis for major multinationals in his career like BASF, Novartis, Sanofi, etc., He has worked in Discovery, Natural products, Bulk drugs, Generics, Intermediates, Fine chemicals, Neutraceuticals, GMP, Scaleups, etc, he is now helping millions, has 9 million plus hits on Google on all Organic chemistry websites. His friends call him worlddrugtracker. His New Drug Approvals, Green Chemistry International, All about drugs, Eurekamoments, Organic spectroscopy international, etc in organic chemistry are some most read blogs He has hands on experience in initiation and developing novel routes for drug molecules and implementation them on commercial scale over a 29 year tenure till date Aug 2016, Around 30 plus products in his career. He has good knowledge of IPM, GMP, Regulatory aspects, he has several International patents published worldwide . He has good proficiency in Technology transfer, Spectroscopy, Stereochemistry, Synthesis, Polymorphism etc., He suffered a paralytic stroke/ Acute Transverse mylitis in Dec 2007 and is 90 %Paralysed, He is bound to a wheelchair, this seems to have injected feul in him to help chemists all around the world, he is more active than before and is pushing boundaries, He has 9 million plus hits on Google, 2.5 lakh plus connections on all networking sites, 25 Lakh plus views on dozen plus blogs, He makes himself available to all, contact him on +91 9323115463, email amcrasto@gmail.com, Twitter, @amcrasto , He lives and will die for his family, 90% paralysis cannot kill his soul., Notably he has 13 lakh plus views on New Drug Approvals Blog in 212 countries......https://newdrugapprovals.wordpress.com/ , He appreciates the help he gets from one and all, Friends, Family, Glenmark, Readers, Wellwishers, Doctors, Drug authorities, His Contacts, Physiotherapist, etc

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WO 2016181414, IVACAFTOR, NEW PATENT, COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH


Image result for COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCHImage result for REDDY SRINIVASA DUMBALAImage result for INDIA ANIMATED FLAG

CSIR, Dr. D. Srinivasa Reddy

WO2016181414, PROCESS FOR THE SYNTHESIS OF IVACAFTOR AND RELATED COMPOUNDS

https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2016181414&recNum=1&maxRec=&office=&prevFilter=&sortOption=&queryString=&tab=PCTDescription

REDDY, Dumbala Srinivasa; (IN).
NATARAJAN, Vasudevan; (IN).
JACHAK, Gorakhnath Rajaram; (IN)

COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH [IN/IN]; Anusandhan Bhawan, Rafi Marg New Delhi 110001 (IN)

The present patent discloses a novel one pot two-step process for the synthesis of ivacaftor and related compounds of [Formula (I)], wherein R1, R2, R3, R4, R5, R6, R7 and Ar1are as described above; its tautomers or pharmaceutically acceptable salts thereof starting from indole acetic acid amides

See Eur J Org Chem, Nov 2015, for an article by the inventors, describing a process for preparing ivacaftor using 4-quinolone-3-carboxylic acid amides. The inventors appear to be based at National Chemical Laboratories of CSIR.

Ivacaftor, also known as N-(2,4-di-tert-butyl-5-hydroxyphenyl)-l,4-dihydro-4-oxoquinoline-3-carboxamide, having the following Formula (A):

Formula (A)

[003] Ivacaftor was approved by FDA and marketed by vertex pharma for the treatment of cystic fibrosis under the brand name KALYDECO® in the form of 150 mg oral tablets. Kalydeco® is indicated for the treatment of cystic fibrosis in patients age 6 years and older who have a G55ID mutation in the CFTR (cystic fibrosis transmembrane conductance regulator)gene.

[004] U.S. 20100267768 discloses a process for preparation of ivacaftor, which involves the coupling of 4-oxo-l,4-dihydro-3- quinoline carboxylic acid with hydroxyl protected phenol intermediate in the presence of propyl phosphonic anhydride (T3P®) followed by deprotection of hydroxyl protection group and optional crystallization with isopropyl acetate. The publication also discloses the use of highly expensive coupling reagent, propyl phosphonic anhydride; which in turn results to an increase in the manufacturing cost. The process disclosed is schematically represented as follows:

[005] Article titled “Discovery of N-(2,4-Di-te -butyl-5-hydroxyphenyl)-4-oxo-l,4-dihydroquinoline-3-carboxamide (VX-770, Ivacaftor), a Potent and Orally Bioavailable CFTR Potentiator” byHadida,S et. al in . Med. Chem., 2014, 57 (23), pp 9776-9795 reportsN-(2,4-di-teri-butyl-5-hydroxyphenyl)-4-oxo- 1 ,4-dihydroquinoline-3-carboxamide (VX-770, 48, ivacaftor), an investigational drug candidate approved by the FDA for the treatment of CF patients 6 years of age and older carrying the G551D mutation.

[006] WO 2014125506 A2 discloses a process for the preparation of ivacaftor in high yield and purity by using novel protected quinolone carboxylic acid compounds as intermediates.

[007] Article titled “Expeditious synthesis of ivacaftor” by Jingshan Shen et. al in Heterocycles, 2014, 89 (4), pp 1035 – 1040 reports an expeditious synthesis for ivacaftor featuring modified Leimgruber-Batcho procedure. The overall yield is 39% over six steps from commercially available 2-nitrobenzoyl chloride.

[008] U.S.2011/064811 discloses a process for preparation of ivacaftor, which involves condensation of 4-oxo-l,4-dihydro-3- quinolone carboxylic acid with 5- amino-2,4-di-(tert-butyl)phenol in the presence of HBTU followed by the formation of ethanol crystalate, which is then treated with diethyl ether to yield ivacaftor as a solid.

[010] U.S. 7,495,103 discloses modulators of ATP-binding cassette transporters such as ivacaftor and a process for the preparation of modulators of ATP-binding cassette transporters such as quinolone compounds. The process includes condensation of 4-oxo-l,4-dihydro-3 -quinolone carboxylic acid with aniline in presence of 2-(lH-7-azabenzotriazol-l-yl)-l,l,3,3-tetramethyluronium hexafluoro phosphate methanaminium (HATU) as shown:

[011] U.S. 2011/230519 discloses a process for preparation of 4-oxo-l,4-dihydro-3-quinoline carboxylic acid by reaction of aniline with diethylethoxymethylenemalonate at 100-110°C followed by cyclization in phenyl ether at temperature 228-232°C and then hydrolysis, as shown below:

[012] US 7,402,674 B2 discloses 7-Phenylamino-4-quinolone-3-carboxylic acid derivatives, process for their preparation and their use as medicaments.

[013] US 4,981,854 discloses l-aryl-4-quinolone-3 carboxylic acids, processes for their preparation and anti-bacterial agents and feed additives containing these compounds.

Article titled “Ozonolysis Applications in Drug Synthesis” by Van Ornum,S.G. ; Champeau,R.M.; Pariza,R. in Chem. Rev., 2006, 106 (7), pp 2990-3001 reports that ozonolysis for the synthesis of numerous interesting bioactive natural products and pharmaceutical agents.

[014] Article titled “Safe Execution of a Large-Scale Ozonolysis: Preparation of the Bisulfite Adduct of 2-Hydroxyindan-2-carbox-aldehyde and Its Utility in a Reductive Animation” by RaganJ.A. et. al. in Org. Proc. Res. Dev., 2003, 7 (2), pp 155-160 reports various routes to bisulfite adduct, the most efficient of which involved vinyl Grignard addition to 2-indanone followed by ozonolysis and workup with aqueous NaHS03 to effect reduction and bisulfite formation in a single pot. The utility of bisulfite adduct is as an aldehyde surrogate in a reductive amination reaction.

[015] The reported methods for the synthesis of ivacaftor suffered from several drawbacks such as harsh conditions, high temperature reactions and use of large excess of polyphosphoric acid and corrosive phosphoryl chloride etc. Furthermore, synthesis of ivacaftor requires use of high performance liquid chromatography (HPLC) techniques for the separation of ivacaftor and their analogues.

[016] Therefore, development of a simple and efficient synthetic route is in urgent need. Accordingly the present inventors developed environmentally benign, cost effective and short synthetic route for the synthesis of ivacaftor and their analogues.

Example 1:

Procedur A:

To a solution of indole acetic acid (500 mg, 2.85 mmol), aniline (2.85 mmol), HOBt (3.4 mmol) in acetonitrile (10 mL), EDC.HCl (3.4 mmol) followed by DIPEA (11.4 mmol) was added, and mixture was stirred for 16 h at ambient temperature. The

reaction mixture was evaporated to dryness, diluted with EtOAc (25 mL), washed with saturated aqueous NaHC03 solution (5 mL), H20 (5 mL), brine (5 mL), and dried over Na2S04. The crude material obtained after removal of solvent was purified by column chromatography (silica gel 230-400 mesh, ethyl acetate – pet ether) to afford corresponding amide as a colorless solid.

[040] Example 2:

2-(lH-indol-3-yl)-N-phenylacetamide (1) :

Yield: 570 mg; 80%; 1H NMR (200MHz, DMSO-d6) δ = 10.95 (brs, 1 H), 10.14 (s, 1 H), 7.64 (d, J = 7.8 Hz, 3 H), 7.47 – 7.24 (m, 4 H), 7.21 – 6.92 (m, 3 H), 3.76 (s, 2H); MS: 273 (M+Na)+.

[041] Example 3:

5-(2-(lH-indol-3-yl)acetamido)-2,4-di-tert-butylphenyl methyl carbonate (2): Yield: 800 mg; 64%; 1H NMR (200 MHz, DMSO-d6) δ = 11.51 (brs, 1 H), 9.41 (s, 1 H), 8.12 (d, J = 7.6 Hz, 1 H), 7.96 – 7.78 (m, 3 H), 7.71 – 7.42 (m, 3 H), 4.34 (s, 3 H), 4.30 (s, 2 H), 1.79 (s, 9 H), 1.64 (s, 9 H); MS: 459 (M+Na)+.

[042] Example 4:

(S)-2-(lH-indol-3-yl)-N-(l-phenylethyl)acetamide (3):

Yield: 620 mg; 78%; 1H NMR (400MHz ,DMSO-d6)5 = 10.88 (brs, 1 H), 8.48 (d, J = 8.1 Hz, 1 H), 7.59 (d, J = 7.8 Hz, 1 H), 7.39 – 7.26 (m, 5 H), 7.25 – 7.16 (m, 2 H), 7.08 (t, J = 7.3 Hz, 1 H), 7.02 – 6.95 (m, 1 H), 4.96 (t, J = 7.3 Hz, 1 H), 3.59 (s, 2H), 1.38 (d, J = 7.1 Hz, 3 H).

[043] Example 5:

N-(4-Fluorophenyl)-2-(lH-indol-3-yl)acetamide (4):

1H NMR (400 MHz, DMSO-d6) : δ 10.93 (brs, 1H), 10.17 (s, 1H), 7.68 – 7.61 (m, 3H), 7.36 (d, J= 8.1 Hz, 1H), 7.27 (d, J= 2.0 Hz, 1H), 7.15 – 7.13 (m, 3H), 7.11 – 6.99 (m, 1H), 3.73 (s, 2H); 13C NMR (100 MHz, DMSO-d6) : δ 170.1, 159.5, 157.1, 136.6, 136.3, 127.7, 124.4, 121.5, 121.3, 121.2, 119.1, 118.9, 115.8, 115.6, 111.8, 108.9, 34.2; MS: 269 (M+H)+

[044] Example 6:

N-(4-Chlorophenyl)-2-(lH-indol-3-yl)acetamide (5):

1H NMR (200 MHz, DMSO-d6): 510.93 (brs, 1H),10.24 (s, 1H), 7.67 – 7.59 (m, 3H), 7.36 – 7.27 (m, 4H), 7.12 – 6.98 (m, 2H), 3.74 (s, 2H); 13CNMR (100 MHz, DMSO-d6): 5170.4, 138.9, 136.7, 129.1, 127.8, 127.1, 124.5, 121.6, 121.2, 119.2, 119.0, 115.7, 111.9, 108.9, 34.3; MS: 285 (M+H)+.

[045] Example 7:

2-(lH-Indol-3-yl)-N-(p-tolyl)acetamide (6) :

1H NMR (400 MHz, DMSO-d6): 510.91 (brs, 1H), 10.01 (s, 1H), 7.62 (d, J= 7.8 Hz, 1H), 7.50 (d, J= 8.6 Hz, 2H), 7.37 (d, J= 8.1 Hz, 1H), 7.29 – 7.26 (m, 1H), 7.10 – 7.07 (m, 3H), 7.01 – 6.99 (m, 1H), 3.71 (s, 2H), 2.23 (s, 3H); 13C NMR (100 MHz, DMSO-de): 5170.0, 137.4, 136.6, 132.4, 129.5, 127.7, 124.3, 121.4, 119.6, 119.2, 118.8, 111.8, 109.1, 34.2, 20.9; MS: 265 (M+H)+.

[046] Example 8:

N-(4-Ethylphenyl)-2-(lH-indol-3-yl)acetamide (7):

XH NMR (400 MHz, DMSO-d6): 510.91 (brs, 1H), 10.01 (s, 1H), 7.61 (s, 1H), 7.52 (d, J= 8.3 Hz, 2H), 7.36 (d, J= 8.1 Hz, 1H), 7.26 (s, 1H), 7.15 – 7.04 (m, 3H), 6.99 (s, 1H), 2.55 (t, J= 7.5 Hz, 2H), 1.15 (t, J= 7.5 Hz, 3H); 13C NMR (100 MHz, DMSO-d6): 5169.9, 138.9, 137.6, 136.6, 128.3, 127.7, 124.3, 121.4, 119.6, 119.2, 118.8, 111.8, 109.1, 40.6, 40.4, 40.2, 40.0, 39.8, 39.6, 39.4, 34.2, 28.0, 16.2; MS: 279 (M+H)+.

[047] Example 9:

2-(lH-Indol-3-yl)-N-(4-propylphenyl)acetamide (8):

1H NMR (400 MHz, DMSO-d6): 58.48 (brs, 1H), 7.64 (d, J = 8.1 Hz, 1H), 7.50 – 7.42 (m, 2H), 7.33 – 7.15 (m, 6H), 7.07 (d, J= 8.3 Hz, 2H), 3.92 (s, 2H), 2.52 (t, J= 7.6 Hz, 2H), 1.65 – 1.53 (m, 2H), 0.91 (t, J= 7.3 Hz, 3H); 13C NMR (100 MHz, DMSO-d6): 5169.7, 138.9, 136.5, 135.2, 128.8, 126.9, 124.0, 122.8, 120.4, 120.1, 118.7, 111.6, 108.7, 37.4, 34.5, 24.6, 13.7; MS: 315 (M+Na)+.

[048] Example 10:

2-(lH-Indol-3-yl)-N-(4-isopropylphenyl)acetamide (9) :

yield 79% ; 1H NMR (400 MHz, DMSO-d6): δ 10.91 (brs, 1H), 10.01 (s, 1H), 7.62 (d, = 7.8 Hz, 1H), 7.55 – 7.49 (m, = 8.6 Hz, 2H), 7.37 (d, = 8.1 Hz, 1H), 7.26 (d, = 2.0 Hz, 1H), 7.18 – 7.11 (m, = 8.6 Hz, 2H), 7.11 – 7.05 (m, 1H), 7.02 – 6.95 (m, 1H), 2.95 – 2.71 (m, 1H), 1.17 (d, = 6.8 Hz, 6H); 13C NMR (100 MHz, DMSO-d6): δ 169.9, 143.5, 137.6, 136.6, 127.7, 126.8, 124.3, 121.4, 119.7, 119.2, 118.8, 111.8, 109.2, 24.4; MS: 315 (M+Na)+.

[049] Example 11:

2-(lH-indol-3-yl)-N-(4-(trifluoromethoxy)phenyl)acetamide (10):

Yield 85% ; 1H NMR (400 MHz, CDC13): δ 8.35 (brs., 1 H), 7.44 – 7.38 (m, 2 H), 7.27 – 7.21 (m, 3 H), 7.12 – 7.05 (m, 1H), 7.03 – 6.95 (m, 2H), 6.93 (d, = 8.6 Hz, 2H), 3.75 (s, 2H); 13C NMR (100 MHz, CDC13): δ 170.0, 145.3, 136.5, 136.2, 126.8, 124.1, 123.0, 121.6, 121.2, 120.5, 118.5, 111.7, 108.2, 34.4; MS: 335 (M+Na)+.

[050] Example 12:

N-(2-chloro-5-methoxyphenyl)-2-(lH-indol-3-yl)acetamide (11):

Yield 75% ; XH NMR (200 MHz, DMSO-d6): δ 10.98 (brs, 1H), 9.27 (s, 1H), 7.59 (d, = 7.8 Hz, 1H), 7.53 (d, = 2.9 Hz, 1H), 7.39 – 7.32 (m, 3H), 7.09 – 6.99 (m, 2H), 6.74 (dd, = 3.0, 8.8 Hz, 1H), 3.85 (s, 2H), 3.71 (s, 3H); 13C NMR (400 MHz, DMSO-d6): δ 170.4, 160.1, 141.1, 136.7, 130.0, 127.8, 124.4, 121.6, 119.2, 119.0, 111.9, 109.1, 105.4, 55.4, 34.4; MS: 315 (M+Na)+.

[051]Example 13:

N-(2-ethylphenyl)-2-(lH-indol-3-yl)acetamide (12):

Yield 78% ; 1H NMR (400 MHz, CDC13): δ 8.68 (brs, 1H), 7.95 (d, = 8.1 Hz, 1H), 7.67 (d, = 7.8 Hz, 1H), 7.48 – 7.44 (m, 2H), 7.29 – 7.23 (m, 1H), 7.22 – 7.20 (m, 3H), 7.05 (d, = 4.4 Hz, 2H), 2.00 (q, = 7.4 Hz, 2H), 0.67 (t, = 7.6 Hz, 3H); 13C NMR (100 MHz, CDC13): δ 169.9, 136.6, 135.0, 134.3, 128.7, 126.7, 125.1, 124.1, 123.0, 122.5, 120.4, 118.7, 111.6, 108.6, 34.4, 24.2, 13.6.

[052] Example 14:

N-(2-bromophenyl)-2-(lH-indol-3-yl)acetamide(13):

Yield 76%; 1H NMR (200 MHz, DMSO-d6): δ 11.00 (brs, 1H), 9.30 (s, 1H), 7.81 -7.77 (m, 1H), 7.63 – 7.56 (m, 2H), 7.41 – 7.35 (m, 3H), 7.11 – 7.05 (m, 3H), 3.85 (s, 2H);13C NMR (100 MHz, DMSO-d6): δ 169.9, 136.2, 132.5, 128.0, 127.2, 126.4, 125.5, 124.4, 121.2, 118.7, 118.5, 116.4, 111.4, 108.0, 33.2.

[053] Example 15:

N-benzyl-2-(lH-indol-3-yl)acetamide (14):

Yield 85%; 1H NMR (400 MHz, DMSO-d6): δ 10.89 (brs., 1H), 8.40 (t, = 5.7 Hz, 1H), 7.57 (d, = 7.8 Hz, 1H), 7.36 (d, = 8.1 Hz, 1H), 7.32 – 7.18 (m, 6H), 7.08 (t, = 7.5Hz, 1H), 7.03 – 6.90 (m, 1H), 4.28 (d, = 5.9Hz, 2H), 3.60 (s, 2H); 13C NMR (100 MHz, DMSO-de): δ 171.2, 140.1, 136.6, 128.7, 127.7, 127.2, 124.3, 121.4, 119.2, 118.7, 111.8, 109.3, 42.7, 33.2.

[054] Example 16:

2-(lH-indol-3-yl)-N-(4-methoxybenzyl)acetamide(15):

Yield 85% ; 1H NMR (400 MHz, DMSO-d6): δ 10.87 (brs, 1 H), 8.32 (t, = 5.6 Hz, 1 H), 7.55 (d, = 7.8 Hz, 1H), 7.35 (d, = 8.1 Hz, 1H), 7.22 – 7.13 (m, 3H), 7.11 – 7.05 (m, 1 H), 7.00 – 6.94 (m, 1H), 6.84 (d, = 8.6 Hz, 2H), 4.20 (d, = 6.1 Hz, 2H), 3.72 (s, 3H), 3.56 (s, 2H); 13C NMR (100 MHz, DMSO-d6): δ 171.1, 158.6, 136.6, 132.0, 129.0, 127.7, 124.2, 121.4, 119.2, 118.7, 114.1, 111.8, 109.4, 55.5, 42.1, 33.2.

[055] Example 17:

N,N-dibenzyl-2-(lH-indol-3-yl)acetamide (16):

Yield 70% ; 1H NMR (400 MHz, DMSO-d6): δ 10.91 (brs, 1H), 7.50 (d, = 7.8 Hz, 1H), 7.37 – 7.34 (m, 3H), 7.30 (d, = 6.6 Hz, 1H), 7.25 – 7.19 (m, 3H), 7.17 (t, = 6.6 Hz, 5H), 7.16 (d, = 7.8 Hz, 1H), 7.00 – 6.97 (m, 1H), 4.59 (s, 2H), 4.50 (s, 2H), 3.86 (s, 2H); 13C NMR (100 MHz, DMSO-d6): δ 171.7, 138.2, 136.6, 129.2, 128.8, 128.1, 127.8, 127.7, 127.5, 127.1, 124.2, 121.5, 119.2, 118.8, 111.8, 108.5, 50.7, 48.4, 31.2.

[056] Example 18:

2-(lH-indol-3-yl)-N-propylacetamide (17):

Yield 75% ; XH NMR (200 MHz, DMSO-d6): δ 10.86 (brs, 1H), 7.88 – 7.80 (m, 1H), 7.56 (d, = 7.6 Hz, 1H), 7.31 (d, = 7.8 Hz, 1H), 7.17 (d, = 2.3 Hz, 1H), 7.06 – 6.92 (m, 2H), 3.48 (s, 2H), 3.00 (q, J = 6.8 Hz, 2H), 1.39 (sxt, / = 7.2 Hz, 2H), 0.88 – 0.75 (t, = 7.2 Hz, 3H); 13C NMR (100 MHz, DMSO-d6): δ 171.0, 136.6, 127.8, 124.2,

121.4, 119.2, 118.7, 111.8, 109.6, 39.4, 33.3, 22.9, 11.9.

[057] Example 19:

N-hexyl-2-(lH-indol-3-yl)acetamide (18) :

Yield 87% ; 1H NMR (400 MHz, DMSO-d6): δ 10.84 (brs, 1H), 7.83 (brs, 1H), 7.54 (d, = 7.8 Hz, 1H), 7.33 (d, = 8.1 Hz, 1H), 7.21 – 7.13 (m, 1H), 7.06 (t, = 7.6 Hz, 1H), 6.96 (t, J = 7.5 Hz, 1H), 3.47 (s, 2H), 3.03 (q, / = 6.8 Hz, 2H), 1.37 (t, = 6.5 Hz, 2H), 1.30 – 1.15 (m, 6H), 0.84 (t, = 6.7 Hz, 3H); 13C NMR (100 MHz, DMSO-d6): δ 170.9, 136.6, 127.7, 124.2, 121.3, 119.1, 118.7, 111.7, 109.5, 39.06, 33.2, 31.5, 29.6, 26.5, 22.5, 14.4.

[058] Example 20:

Methyl (2-(lH-indol-3-yl)acetyl)-L-alaninate (19):

Yield 79% ; 1H NMR (400 MHz, CDC13): δ 8.53 (brs, 1H), 7.60 (d, = 7.8 Hz, 1H), 7.41 (d, = 8.1 Hz, 1H), 7.25 – 7.23 (m, 1H), 7.19 – 7.14 (m, 2H), 6.27 (d, = 7.3 Hz, 1H), 4.63 (t, = 7.3 Hz, 1H), 3.78 (s, 2H), 3.68 (s, 3H), 1.31 (d, = 7.3 Hz, 3H); 13C NMR (100 MHz, CDC13): δ 173.4, 171.2, 136.4, 127.0, 123.8, 122.5, 119.9, 118.7,

111.5, 108.5, 52.4, 48.0, 33.3, 18.2.

[059] Example 21:

-(6-chloro-lH-indol-3-yl)-N-phenylacetamide(20):

To a solution of 6-Chloro indole 20a (300 mg, 1.98 mmol )in anhydrous THF, Oxalyl chloride (186 μΤ, 276 mg, 2.18 mmol) was added and the mixture stirred at room temperature. After 2 h, N,N-Diisopropylethylamine (758 μΤ, 562 mg, 4.35 mmol) was

introduced to the mixture, followed by the aniline (221.0 mg, 2.37 mmol). The temperature was raised to 45 °C, and heating continued for 18 h. The solvent was evaporated, and then mixture was diluted with EtOAC (15 mL), washed with brine and dried over anhydrous Na2S04. The crude material obtained after removal of solvent was purified by column chromatography (10 – 20% EtOAc : Petroleum ether) to afford 20b (295 mg, 51% yield) as a yellow coloured solid. IR Omax(film): 3346, 3307,2853, 1724, 1678 cm“1; 1H NMR (400 MHz, DMSO-d6): δ 12.40 (br. s., 1H), 10.68 (s, 1H), 8.79 (d, = 3.2 Hz, 1H), 8.25 (d, = 8.6 Hz, 1H), 7.85 (d, = 7.8 Hz, 2H), 7.62 (d, = 1.7 Hz, 1H), 7.41 – 7.30 (m, 3H), 7.19 – 7.13 (m, 1H); 13C NMR (100 MHz, DMSO-d6): δ 182.5, 162.5, 140.0, 138.4, 137.4, 129.2, 128.5, 125.4, 124.8, 123.4, 122.9, 120.8, 113.0, 112.3; HRMS (ESI) Calculated for Ci6HnN2OCl[M+H]+: 299.0582, found 299.0580;

A solution of 20b (300 mg, 0.99 mmol) dissolved in MeOH (40 mL) was added to NaBH4 (45 mg, 1.23 mmol). The reaction was stirred for 4h and then added to saturated solution of Na2S04. The reaction mixture was further stirred for lh and then filtered through Celite.The filtrate obtained was concentrated in vacuo, and then mixture was diluted with EtOAc (15 mL), washed with brine and dried over anhydrous Na2S04. The crude material obtained after removal of solvent was forwarded for next step without further purification.In an N2 atmosphere, TMSC1 (1.272 mL, 9.9 mmol) in CH3CN (40 mL) was added to sodium iodide (1.488 mg, 9.9 mmol) and stirred for 2h. The reaction mixture was cooled to 0 °C and a solution of above crude alcohol (0.99 mmol) in CH3CN (10 mL) was then added drop wise over 30 min, followed by stirring for 3h. The reaction mixture was poured into NaOH (7g in 40 mL of water) and then extracted with ethyl acetate (15×2). The organic layer was washed with aq.Na2S203, dried over Na2S04 and concentrated in vacuo. The residue was chromatographed on silica gel (EtOAc:Pet ether) to afford 20 as a off white solid (two steps 38 % ); IR Umax(film): 3273, 3084,2953, 2857, 1629, 1562 cm“1; 1H NMR (400 MHz, DMSO-d6): δ 11.06 (br. s., 1H), 10.13 (br. s., 1H), 7.62 – 7.57 (m, 3H), 7.40 (s, 1H), 7.30 – 7.25 (m, 3H), 7.04 – 6.99 (m, 2H), 3.71 (s, 2H); 13C NMR (100 MHz, DMSO-d6): δ 170.1,

139.7, 136.9, 129.2, 126.5, 126.3, 125.5, 123.7, 120.6, 119.6, 119.3, 111.5, 109.4, 34.0; HRMS (ESI):Calculated for Ci6Hi4N2OCl[M+H]+: 285.0789, found 285.0786.

[060] Example 22:

2-(5-chloro-lH-indol-3-yl)-N-phenylacetamide(21):

21a 21b 21

To a solution of 5-Chloro indole 21a (300 mg, 1.98 mmol )in anhydrous THF(20 mL), Oxalyl chloride (186 ^L, 276 mg, 2.18 mmol) was added and the mixture stirred at room temperature. After 2 h, N,N-diisopropylethylamine (758 μΕ, 562 mg, 4.35 mmol) was introduced to the mixture, followed by the aniline (221.0 mg, 2.37 mmol). The tempera ture was raised to 45 °C, and heating continued for 18 h. The solvent was evaporated, and then mixture was diluted with EtOAC (15 mL), washed with brine and dried over anhydrous Na2S04. The crude material obtained after removal of solvent was purified by column chromatography (10 – 20% EtOAc : Petroleum ether) to afford (21b) (305 mg, 53% yield) as a yellow coloured solid. IR rjmax(film): 3346, 3307,2853, 1724, 1678 cm“1; 1H NMR (400 MHz, DMSO-d6): δ 12.40 (br. s., 1H), 10.68 (s, 1H), 8.79 (d, = 3.2 Hz, 1H), 8.25 (d, = 8.6 Hz, 1H), 7.85 (d, = 7.8 Hz, 2H), 7.62 (d, = 1.7 Hz, 1H), 7.42 – 7.30 (m, 3H), 7.20 – 7.14 (m, 1H); 13C NMR (100 MHz, DMSO-d6): δ 182.4, 162.4, 140.3, 138.4, 135.4, 129.2, 127.9, 124.8, 124.1, 120.8, 114.8, 112.0; HRMS (ESI) Calculated for Ci6HnN2OCl[M+H]+: 299.0582, found 299.0580; A solution of 21b (200 mg, 0.66 mmol) dissolved in MeOH (30 mL) was added to NaBH4 (30 mg, 0.82 mmol). The reaction was stirred for 4h and then added to saturated solution of Na2S04. The reaction mixture was further stirred for lh and then filtered through Celite. The filtrate obtained was concentrated in vacuo, and then mixture was diluted with EtOAc (15 mL), washed with brine and dried over anhydrous Na2S04. The crude material obtained after removal of solvent was forwarded for next step without further purification. In an N2 atmosphere, TMSC1 (848 mL, 6.6 mmol) in CH3CN (25 mL) was added to sodium iodide (992 mg, 6.6 mmol) and stirred for 2h. The reaction mixture was cooled to 0 °C and a solution of above crude alcohol(0.66 mmol) in CH3CN (5 mL) was then added dropwise over 30 min, followed by stirring for 3h. The reaction mixture was poured into NaOH (5g in 30 mL of water) and then extracted with ethyl acetate(15×2). The organic layer was washed with aq.Na2S203, dried over Na2S04 and concentrated in vacuo. The residue was chromatographed on silica gel (EtOAc:Pet ether) to afford 22 as a off white solid (two steps 42 % ); IR Umax(film): 3273, 3084,2955, 2857, 1629, 1562 cm“1; 1H NMR (400 MHz, DMSO-d6): δ 11.13 (br. s., 1H), 10.11 (s, 1H), 7.67 (s, 1H), 7.60 (d, = 7.8 Hz, 2H), 7.39 – 7.27 (m, 4H), 7.13 – 7.02 (m, 2H), 3.16 (s, 2H); 13C NMR (100 MHz, DMSO-d6): δ 169.9, 139.8, 135.0, 129.2, 128.9, 126.2, 123.6, 121.4, 119.6, 118.6, 113.4, 109.0, 34.0; HRMS (ESI) Calculated for Ci6H14N2OCl[M+H]+: 285.0789, found 285.0786.

[061] Example 23:

2-(l-benzyl-lH-indol-3-yl)-N-phenylacetamide (22):

Yield 79% ; 1H NMR (400 MHz, DMSO-d6): δ 7.67 (d, = 7.8 Hz, 1H), 7.54 (brs, 1H), 7.43 – 7.31 (m, 6H), 7.31 – 7.25 (m, 3H), 7.23 – 7.15 (m, 4H), 7.12 – 7.06 (m, 1H), 5.36 (s, 2H), 3.91 (s, 2H); 13C NMR (100 MHz, DMSO-d6): δ 169.7, 137.7, 137.2, 137.0, 128.9, 128.9, 127.9, 127.6, 126.9, 124.3, 122.7, 120.2, 119.9, 119.0, 110.2, 107.9, 77.4, 77.1, 76.8, 50.1, 34.5.

[062] Example 24:

Procedure B:

2-(lH-indol-3-yl)-N-phenylacetamidel(100 mg; 0.4 mmol) was dissolved in DCM:MeOH(50 mL; 5: 1), then a stream of 03 was passed through the solution until a blue color developed (10 min). The 03 stream was continued for 4 min. Then surplus O3 was removed by passing a stream of 02 through the solution for 10 min or until the blue colorcompletely vanished. Afterwards pyridine (0.1 mL;1.2mmol) was added to the cold (- 78 °C) mixture. The mixture was allowed to warm to room temperature (1 h) and then Et3N (0.35 mL; 2.4 mmol) were added. After stirring at room temperature overnight the reaction mass was concentrated under reduced pressure to dryness, diluted with EtOAc (30 mL), washed with H20 (5 mL), brine (5 mL), and dried over Na2S04. The crude material obtained after removal of solvent was purified by column chromatography (silica gel 230-400 mesh, MeOH – DCM) to give desired quinolone carboxamide as colorless solid.

[063] Example 25:

4-oxo-N-phenyl-l,4-dihydroquinoline-3-carboxamide (23):

Yield: 65 mg; 62%; XH NMR (200MHz ,DMSO-d6) δ = 12.97 (brs, 1 H), 12.49 (s, 1 H), 8.89 (s, 1 H), 8.33 (d, J = 8.2 Hz, 1 H), 7.91 – 7.69 (m, 4 H), 7.62 – 7.50 (m, 1 H), 7.37 (t, J = 7.8 Hz, 2 H), 7.18 – 7.01 (m, 1 H); MS: 287 (M+Na)+.

[064] Example 26:

2,4-di-tert-butyl-5-(4-oxo-l,4-dihydroquinoline-3-carboxamido)phenyl methyl carbonate (24):

Yield: 35 mg; 34%; 1H NMR (400MHz ,DMSO-d6) δ = 12.96 (brs, 1 H), 12.08 (s, 1 H), 8.94 – 8.82 (m, 1 H), 8.44 – 8.28 (m, 1 H), 7.86 – 7.79 (m, 1 H), 7.78 – 7.73 (m, 1 H), 7.59 (s, 1 H), 7.53 (t, J = 7.5 Hz, 1 H), 7.39 (s, 1 H), 3.86 (s, 3 H), 1.46 (s, 9 H), 1.32 (s, 9 H).

[065] Example 27:

(S)-4-oxo-N-(l-phenylethyl)-l,4-dihydroquinoline-3-carboxamide (25):

Yield: 56 mg; 53%; 1H NMR (500MHz ,DMSO-d6) δ = 12.75 (brs, 1H), 10.54 (d, J = 7.6 Hz, 1H), 8.73 (brs, 1H), 8.28 (d, J = 7.9 Hz, 1H), 7.78 (d, J = 7.9 Hz, 1H), 7.73 -7.68 (m, 1 H), 7.50 (t, J = 7.5 Hz, 1 H), 7.42 – 7.34 (m, 4 H), 7.29 – 7.23 (m, 1 H), 5.18 (t, J = 7.2 Hz, 1 H), 1.50 (d, J = 6.7 Hz, 3 H).

[066] Example 28:

Synthesis of ivacaftor (26):

To a solution of 2,4-di-tert-butyl-5-(4-oxo-l,4-dihydroquinoline-3-carboxamido)phenyl methyl carbonate 5 (30 mg, 0.06mmol) in MeOH (2 mL) was added NaOH (5.3 mg, 0.13mmol) dissolved in H20 (2 mL), and the reaction mixture was stirred at room temperature for 5h. Reaction mass was evaporated to one third of its volume (temperature not exceeding 40°C) and acidified with aq.2N HC1 to pH 2-3. The resulting precipitate was collected by suction filtration give desired compound 7 (19 mg, 76%) as off white solid H NMR (400MHz ,DMSO-d6) δ = 12.88 (d, J = 6.6 Hz, 1 H), 11.81 (s, 1 H), 9.20 (s, 1 H), 8.86 (d, J = 6.6 Hz, 1 H), 8.32 (d, J = 7.8 Hz, 1 H), 7.88 – 7.65 (m, 2 H), 7.51 (t, J = 7.5 Hz, 1 H), 7.16 (s, 1 H), 7.10 (s, 1 H), 1.38 (s,9H), 1.36 (s, 9H).

[067] Example 29:

N-(4-fluorophenyl)-4-oxo-l,4-dihydroquinoline-3-carboxamide (27):

Yield 56% ; 1H NMR (400 MHz, DMSO-d6): δ 12.96 (br. s., 1H), 12.50 (s, 1H), 8.88 (s, 1H), 8.33 (d, = 7.3 Hz, 1H), 7.86 – 7.72 (m, 4H), 7.54 (t, = 7.3 Hz, 1H), 7.20 (t, = 8.8 Hz, 2H); 13C NMR (400 MHz, DMSO-d6): δ 176.8, 163.2, 159.7, 157.3, 144.6, 139.6, 135.7, 133.5, 126.4, 125.9, 125.8, 121.8, 119.7, 116.1, 115.9, 110.9.

[068] Example 30:

N-(4-chlorophenyl)-4-oxo-l,4-dihydroquinoline-3-carboxamide (28):

Yield 51% ; 1H NMR (400 MHz, DMSO-d6): δ 13.00 (brs., 1H), 12.59 (br. s., 1H), 8.89 (s, 1H), 8.34 (d, = 7.6 Hz, 1H), 7.83 – 7.76 (m, 4H), 7.56 (s, 1H), 7.42 (d, = 7.9 Hz, 2H); 13C NMR (400 MHz, DMSO-d6): δ 176.8, 163.4, 144.7, 139.6, 138.2, 133.5, 129.4, 127.4, 126.4, 125.9, 125.8, 121.6, 119.7, 110.8.

[069] Example 31:

4-oxo-N-(p-tolyl)-l,4-dihydroquinoline-3-carboxamide (29):

Yield 57% ; 1H NMR (400 MHz, DMSO-d6): δ 12.94 (brs., 1H), 12.40 (s, 1H), 8.88 (s, 1H), 8.33 (d, = 7.8Hz, 1H), 7.82 – 7.80 (m, 1H), 7.76 – 7.7 (m, 1H), 7.63 (d, = 8.3 Hz, 2H), 7.53 (t, = 7.3 Hz, 1H), 7.17 (d, = 8.1 Hz, 2H), 2.29 (s, 3H); 13C NMR (100 MHz, DMSO-de): δ 176.8, 163.1, 144.5, 139.6, 136.8, 133.4, 132.8, 129.9, 126.4, 125.9, 125.7, 120.0, 119.6, 111.1, 20.9; HRMS (ESI):Calculated for Ci7H1502N2[M+H]+: 279.1128, found 279.1127.

[070] Example 32:

N-(4-ethylphenyl)-4-oxo-l,4-dihydroquinoline-3-carboxamide (30):

Yield 51% ; 1H NMR (400 MHz, DMSO-d6): δ 12.95 (br. s., 1H), 12.40 (d, = 7.8 Hz, 1H), 8.87 (d, = 6.1 Hz, 1H), 8.33 (d, = 8.1 Hz, 1H), 7.81 – 7.76 (m, 2H), 7.66 – 7.62 (m, = 8.3 Hz, 2H), 7.53 (t, 7 = 7.5 Hz, 1H), 7.22 – 7.17 (m, = 8.3 Hz, 2H), 2.58 (q, = 7.6 Hz, 2H), 1.18 (t, = 7.6 Hz, 3H); 13C NMR (400 MHz, DMSO-d6): δ 181.5, 167.8, 149.3, 144.3, 144.0, 141.7, 138.2, 133.4, 131.1, 130.7, 130.5, 124.8, 124.4, 115.9, 32.8, 20.9.

[071] Example 33:

4-Oxo-N-(4-propylphenyl)-l,4-dihydroquinoline-3-carboxamide (31):

Yield 51%; 1H NMR (500 MHz, DMSO-d6): δ12.93 (brs, 1H), 12.40 (s, 1H), 8.87 (s, 1H), 8.36 – 8.29 (m, 1H), 7.86 – 7.78 (m, 1H), 7.75 (d, J= 7.9 Hz, 1H), 7.68 – 7.61 (m, J= 8.2 Hz, 2H), 7.54 (t, J= 7.6 Hz, 1H), 7.22 – 7.14 (m, J= 8.2 Hz, 2H), 2.55 – 2.51 (m, 2H), 1.64 – 1.53 (m, 2H), 0.90 (t, J= 7.3 Hz, 3H); 13C NMR (500 MHz, DMSO-d6): 176.8, 163.1, 144.5, 139.6, 137.6, 137.0, 133.5, 129.3, 126.4, 125.9, 125.7, 120.0, 119.7, 111.1, 37.2, 24.6, 14.1.

[072] Example 34:

N-(4-isopropylphenyl)-4-oxo-l,4-dihydroquinoline-3-carboxamide (32):

Yield 46% ; 1H NMR (500 MHz, DMSO-d6): δ 12.93 (br. s., 1H), 12.40 (br. s., 1H), 8.89 – 8.86 (m, 1H), 8.33(d, = 7.6 Hz, 1H), 7.81 – 7.50 (m, 5H), 7.25 – 7.21 (m, 2H), 2.90-2.83 (m, 1H), 1.22-1. l l(m, 6H); 13C NMR (100 MHz, DMSO-d6): δ 176.8, 163.1, 144.5, 143.9, 139.6, 137.1, 133.4, 127.2, 126.4, 125.9, 125.7, 120.1, 119.6, 111.1, 33.4, 24.4.

[073] Example 35:

4-oxo-N-(4-(trifluoromethoxy)phenyl)-l,4-dihydroquinoline-3-carboxamide(33):

Yield 57% ; 1H NMR (400 MHz, DMSO-d6): δ 12.98 (br. s., 1H), 12.63 (s, 1H), 8.88 (d, = 4.9 Hz, 1H), 8.32 (d, = 7.8 Hz, 1H), 7.89 – 7.83 (m, = 8.8 Hz, 2H), 7.79 (d, = 7.6 Hz, 1H), 7.77 – 7.73 (m, 1H), 7.53 (t, J = 7.5 Hz, 1H), 7.40 – 7.34 (m, = 8.6 Hz, 2H); 13C NMR (100 MHz, DMSO-d6): δ 176.8, 163.5, 144.7, 144.0, 139.5, 138.5, 133.5, 126.3, 125.9, 125.8, 122.3, 121.4, 119.7, 110.7.

[074] Example 36:

N-(2-chloro-5-methoxyphenyl)-4-oxo-l,4-dihydroquinoline-3-carboxamide(34):

Yield 54% ; XH NMR (400 MHz, DMSO-d6): δ 12.98 (br. s., 1H), 12.49 (s, 1H), 8.88 (s, 1H), 8.33 (d, = 7.8 Hz, 1H), 7.83 – 7.75 (m, 1H), 7.56-7.48 (m, 3H), 7.27 – 7.21 (m, 1H), 6.67 (d, = 7.8 Hz, 1H), 3.77 (s, 3H); 13C NMR (400 MHz, DMSO-d6): δ 176.8, 163.4, 160.2, 144.7, 140.4, 139.6, 133.5, 130.3, 126.4, 125.9, 125.8, 119.7, 112.3, 111.0, 109.5, 105.7, 55.5.

[075] Example 37:

N-(2-ethylphenyl)-4-oxo-l,4-dihydroquinoline-3-carboxamide(35):

Yield 58% ; 1H NMR (400 MHz, DMSO-d6): δ 12.94 (br. s., 1H), 12.37 (s, 1H), 8.90 (s, 1H), 8.36 (dd, = 8.1, 1.4 Hz, 2H), 8.32 (dd, = 8.1, 1.4 Hz, 2H), 7.82 – 7.74 (m, 1H), 7.53- 7.19 (m, 3H), 7.15 – 7.06(m, 1H), 2.79 (q, = 7.3 Hz, 2H), 1.26 (t, = 7.5 Hz, 3H); 293 (M+H)+.

[076] Example 38:

N-(2-bromophenyl)-4-oxo-l,4-dihydroquinoline-3-carboxamide(36):

Yield 47% ; 1H NMR (200 MHz, DMSO-d6): δ 12.98 (br. s., 1H), 12.69 (s, 1H), 8.90 (d, = 5.9 Hz, 1H), 8.54 (dd, 7 = 1.4, 8.3 Hz, 1H), 8.34 (d, = 7.6 Hz, 1H), 7.86 – 7.67 (m, 3H), 7.57 – 7.49 (m, 1H), 7.40 (t, = 7.2 Hz, 1H), 7.10 – 7.05 (m, 1H); 13C NMR (100 MHz, DMSO-de): δ 176.7, 163.7, 145.0, 139.5, 137.7, 133.5, 133.1, 128.6, 126.4, 126.0, 125.8, 125.3, 122.9, 119.7, 113.4, 110.8.

[077] Example 39:

N-benzyl-4-oxo-l,4-dihydroquinoline-3-carboxamide(37):

Yield 58% ; 1H NMR (400 MHz, CD3OD-d6): δ 8.82 (s, 1 H), 8.35 (d, = 8.1 Hz, 1 H), 7.79 – 7.77 (m, 1 H), 7.65 (d, = 8.3 Hz, 1 H), 7.52 (t, = 7.6 Hz, 1 H), 7.42 – 7.34 (m, 4 H), 7.31 – 7.26 (m, 1 H), 4.67 (s, 2 H); 13C NMR (400 MHz, DMSO-d6): δ 176.6, 165.0, 144.2, 140.0, 139.5, 133.2, 128.9, 128.7, 127.8, 127.3, 126.6, 125.9, 125.4, 119.5, 111.2, 42.6.

[078] ] Example 40:

N-(4-methoxybenzyl)-4-oxo-l,4-dihydroquinoline-3-carboxamide(38):

Yield 56% ; 1H NMR (400 MHz, DMSO-d6): δ 12.73 (br. s., 1H), 10.35 (t, = 5.3 Hz, 1H), 8.78 (d, = 6.1 Hz, 1H), 8.24 (d, = 8.1 Hz, 1H), 7.76 (d, = 7.1 Hz, 1H), 7.73 -7.68 (m, 1H), 7.48 (t, = 7.5 Hz, 1H), 7.28 (d, = 8.3 Hz, 2H), 6.91 (d, = 8.1 Hz, 2H), 4.49 (d, = 5.6 Hz, 2H), 3.74 (s, 3H); 13C NMR (100 MHz, DMSO-d6): δ 176.6, 164.8, 158.8, 144.1, 139.5, 133.1, 131.9, 129.2, 126.6, 125.8, 125.4, 119.5, 114.3, 111.3, 55.5, 42.0.

[079] Example 41:

N,N-dibenzyl-4-oxo-l,4-dihydroquinoline-3-carboxamide(39):

Yield 43% ; 1H NMR (400 MHz, DMSO-d6): δ 12.21 (br. s., 1H), 8.27 (d, = 4.9 Hz, 1H), 8.21 (d, = 7.6 Hz, 1H), 7.49 – 7.41 (m, 2H), 7.41 – 7.35 (m, 3H), 7.33 – 7.20 (m, 5H), 7.20 – 7.11 (m, 7 = 7.1 Hz, 2H), 4.59 (br. s., 2H), 4.42 (s, 2H).

[080] Example 42:

4-oxo-N-propyl-l,4-dihydroquinoline-3-carboxamide(40):

Yield 47% ;1H NMR (400 MHz, DMSO-d6): δ 12.7 (br.s., 1H)10.05 (t, = 5.5 Hz, 1H), 8.74 (s, 1H), 8.26 (d, = 8.1 Hz, 1H), 7.83 – 7.66 (m, 2H), 7.52 – 7.44 (m, 1H), 3.33 – 3.22 (m, 2H), 1.61 – 1.49 (m, 2H), 0.93 (t, = 7.5 Hz, 3H); 13C NMR (100 MHz, DMSO-de): δ 176.6, 164.8, 143.9, 139.5, 133.1, 126.6, 125.9, 125.3, 119.4, 111.4, 39.3, 23.1, 12.0

[081] Example 43:

N-hexyl-4-oxo-l,4-dihydroquinoline-3-carboxamide(41):

Yield 51% ;1H NMR (400 MHz, DMSO-d6): δ 12.68 (m, 1H), 10.02 (t, = 5.5 Hz, 1H), 8.73 (d, = 6.1 Hz, 1H), 8.27 – 8.25 (m, 1H), 7.77 – 7.67 (m, 2H), 7.47 (t, = 7.5 Hz, 1H), 3.33 – 3.29 (m, 2H), 1.56 – 1.45 (m, 2H), 1.34 – 1.25 (m, 6H), 0.88 – 0.82 (m, 3H); 13C NMR (100 MHz, DMSO-d6): δ 176.6, 164.8, 143.9, 139.5, 133.1, 126.6, 125.9, 125.3, 119.4, 111.4, 38.7, 31.5, 29.8, 26.7, 22.5, 14.4.

[082] Example 44:

Methyl (4-oxo-l,4-dihydroquinoline-3-carbonyl)-L-alaninate(42):

Yield 38% ; 1H NMR (400 MHz, CD3OD): δ 8.74 (s, 1H), 8.47 – 8.29 (m, 1H), 7.86 -7.76 (m, 1H), 7.64 (d, = 8.3 Hz, 1H), 7.58 – 7.44 (m, 1H), 4.69 (d, = 7.3 Hz, 1H), 3.79 (s, 3H), 1.55 (d, = 7.3 Hz, 3H); 13C NMR (100 MHz, CD3OD): δ 177.3, 173.3, 165.5, 143.6, 139.2, 132.9, 126.3, 125.4, 125.2, 118.5, 110.3, 51.5, 47.0, 17.0.

[083] Example 45:

7-chloro-4-oxo-N-phenyl-l,4-dihydroquinoline-3-carboxamide(43):

Yield 48% ; IR Omax(film): 2920, 2868, 1661, 1601 cm” 1; 1H NMR (400 MHz, DMSO-de): δ 12.91 (br. s., 1H), 12.30 (s, 1H), 8.90 (s, 1H), 8.29 (d, = 8.8 Hz, 1H), 7.80 -7.67 (m, 3H), 7.58 – 7.51 (m, 1H), 7.36 (t, = 7.7 Hz, 2H), 7.09 (t, = 7.3 Hz, 1H); 13C NMR (100 MHz, DMSO-d6): δ 176.3, 162.9, 145.4, 140.3, 139.2, 138.0, 129.5, 128.2, 126.1, 125.1, 123.9, 120.1, 118.8, 111.6.

[084] Example 46:

6-chloro-4-oxo-N-phenyl-l,4-dihydroquinoline-3-carboxamide(44):

Yield 52% ; 1H NMR (400 MHz, DMSO-d6): δ 13.05 (brs, 1H), 12.27 (s, 1H), 8.88 (s, 1H), 8.21 (d, = 2.2 Hz, 1H), 7.86 – 7.67 (m, 4H), 7.36 (t, = 7.8 Hz, 2H), 7.16 – 7.04 (m, 1H); 13C NMR (100 MHz, DMSO-d6): δ 175.6, 162.9, 144.9, 139.1, 138.2, 133.5, 130.4, 129.5, 127.5, 124.9, 123.9, 122.0, 120.1, 111.4.

[085] Example 47:

l-benzyl-4-oxo-N-phenyl-l,4-dihydroquinoline-3-carboxamide(45)

Yield 55% ; 1H NMR (400 MHz, DMSO-d6): δ 12.30 (s, 1H), 9.05 (s, 1H), 8.60 (dd, = 1.7, 8.1 Hz, 1H), 7.82 (d, = 7.8 Hz, 2H), 7.69 – 7.62 (m, 1H), 7.55 – 7.45 (m, 2H), 7.43 – 7.34 (m, 5H), 7.24 – 7.18 (m, 2H), 7.17 – 7.10 (m, 1H), 5.53 (s, 2H); 13C NMR (100 MHz, DMSO-d6): δ 176.9, 162.9, 148.7, 139.3, 138.7, 134.1, 133.1, 129.4, 128.9, 128.7, 128.0, 127.4, 126.2, 125.5, 123.9, 120.5, 116.9, 112.3, 57.9; HRMS (ESI): Calculated for C23H1802N2Na [M+Na]+: 377.1260, found 377.1259; MS: 355 (M+H)+.

[086] Advantages of invention:

1. Cost-effective process for synthesis.

2. Carried out at environmentally benign conditions.

3. Short synthetic route.

4. Useful for making several related compounds of medicinal

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DR SRINIVASA REDDY recieving NASI – Reliance Industries Platinum Jubilee Award (2015) for Application Oriented Innovations in Physical Sciences.

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MYSELF WITH HIM

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From left to right: Dr. D. Srinivasa Reddy, Shri Y. S. Chowdary, Dr. Harsh Vardhan, Dr. Girish Sahni

  • Dr D. Srinivasa Reddy receiving the prestigious “SHANTI SWARUP BHATNAGAR” award at the occasion of the 75th Foundation day of CSIR.

Shanti Swarup Bhatnagar awardees with the honorable Prime Minister of India

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NCL PUNE

DSR Group

//////////WO-2016181414, WO 2016181414,  IVACAFTOR, new patent, COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH,  Anusandhan Bhawan, Rafi Marg New Delhi, INDIA, CSIR, Dr. D. Srinivasa Reddy

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IPRAGLIFLOZIN, NEW PATENT, WO2016173551, China State Institute of Pharmaceutical Industry; Shanghai Institute of Pharmaceutical Industry


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WO 2016173551 China State Institute of Pharmaceutical Industry; Shanghai Institute of Pharmaceutical Industry

https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2016173551&redirectedID=true

MA, Shuai; (CN).
ZHOU, Weicheng; (CN)

WO2016173551,  IPRAGLIFLOZIN PREPARATION METHOD

CHINA STATE INSTITUTE OF PHARMACEUTICAL INDUSTRY [CN/CN]; 4th Floor, Building 1, No.1111 Halley Road,pudong New Area Shanghai 201203 (CN).
SHANGHAI INSTITUTE OF PHARMACEUTICAL INDUSTRY [CN/CN]; No.1320,West Beijing Road,Jing’an District Shanghai 200040 (CN)

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MACHINE TRANSLATED FROM CHINESE……

Ignatius column Net (English name: Ipragliflozin) by Astellas Pharma Ltd. (Astellas) new sodium life Pharmaceutical Co., Ltd. (Kotobuki) R & D – glucose cotransporter (Sodium glucose co-transporters, referred to as SGLT-2 ) inhibitor, on January 17, 2014 in the Japanese market for the treatment of patients with type ⅱ diabetes; tradename Suglat, currently provide 25mg and 50mg tablets.

 

Chemical Name column Ignatius net is (1S) -1,5- dehydration -1-C- [3- (1- benzothien-2-yl-methyl) -4-fluorophenyl] -D-glucose alcohols of the formula the C 21 the H 21 the FO 5 the S, the CAS No. 761423-87-4, as the structure of formula 2, as a column for medicinal Eagle with L- proline net clinical eutectics, such as a structural formula FIG.

 

 

Ignatius column in the process of preparation of the net, the chiral synthesis of β glycoside bond synthetic route key points. Currently, Ignatius column net of synthetic methods reported in the literature there are several of these methods for the synthesis of chiral β-glucoside bonds mainly relates to hydroxy-protected D- glucose lactone ester carbonyl nucleophilic addition reaction.

 

Route One: Patent WO2004080990 synthetic route reported net Ignatius column is as follows:

 

This route, [1-benzopyran-2-yl (5-bromo-2-fluorophenyl) methoxy] (tert-butyl) dimethylsilane (Compound 10) with n-butyl lithium at -78 deg.] C (or minus 78 deg.] C) the reaction of an organolithium reagent and then with 2,3,4,6-tetra -O- benzyl -D- glucose lactone (compound 9) nucleophilic addition at low temperature -78 ℃ to obtain compound 8, followed by removal of the silicon compound 8 hydroxy group is protected with tetrabutylammonium fluoride (of TBAF) to give compound 7, triethylsilane and then reducing the compound 7 obtained with chiral β glycosidic bond Ignatius column net intermediate 6, the last off at -78 ℃ intermediate ring 6 sugar hydroxyl protecting groups to obtain the desired product – Ignatius column net (compound 2). Compound 10 was prepared by the target product – Ignatius column net synthesis route yield 9.94%, net Ignatius column purity not reported. The disadvantage of this method is that a long synthetic route, after every step of the reaction were purified by column chromatography, and the yield is low. Deprotecting the hydroxy group on two key steps chiral β glycosidic bond synthesis and sugar ring need to be at a low temperature at -78 deg.] C, clearly, it is difficult to meet the needs of industrial production.
Route II: Patent WO2008075736 Ignatius column reported net synthetic route is as follows:

 

 

The route of 2- (5-bromo-2-fluorobenzyl) benzothiophene (compound 15) with n-butyl lithium at -43.5 ~ -33.3 ℃ reaction of an organolithium reagent and then with 2,3,4 , 6-tetrafluoro -O- trimethylsilyl -D- glucose lactone (compound 14) nucleophilic addition reactions at -72.6 ~ -65 ℃ to give compound 13, compound 13 and then acetylation, reduction Ignatius column net intermediates prepared with chiral β glycoside bond of 11, finally deacetylated to obtain the desired product of intermediate 11 – Ignatius column net (compound 2). Compound 15 was prepared by the Scheme 2 the desired product in a yield of 72.46%, a purity of compound 2 was 99%. The disadvantage of this method is that the route Ignatius column net synthesis requires at a low temperature of -72.6 ℃ to react and involve nucleophilic addition reaction, a hydroxyl group on the terminal carbon methylation, acetylation of hydroxyl groups on the sugar ring, the end methoxy groups on carbon reduction, the reaction and post-treatment process is very complicated, more difficult to industrial production, and on the terminal carbon-methoxy-reducing agent used in the reduction – t-butyldimethylsilyl more expensive, increasing the whole synthetic route costs.

 

Route III: Patent WO2015012110 Ignatius column reported net synthetic route is as follows:

 

On the basis of patent WO2015012110 patent WO2008075736 reported synthetic route for the synthesis net Ignatius column primarily relates to the further improvements: namely: 2- (5-bromo-2-fluorobenzyl) benzothiophene (Compound 15) three butylmagnesium lithium at -12 ~ -26 ℃ organomagnesium reagent prepared by the reaction – compound 16, and then with 2,3,4,6-tetra -O- trimethylsilyl -D- glucose lactone (compound 14) carried out at -12 ~ -16 ℃ nucleophilic addition reaction Ignatius column net key intermediates – compounds 13, this step is nucleophilic addition reaction temperature was raised to -26 ℃, avoid the use of other organic lithium reagent required -78 ℃ low temperature reactions. The disadvantage of this method is that Ignatius column net synthesis still need to involve nucleophilic addition reaction, a hydroxyl group on the terminal carbon methylation, acetylation of hydroxyl groups on the sugar ring, a methoxy group on the terminal carbon reduction reaction and post-treatment very complicated problem is not resolved; in addition, tributyltin lithium magnesium used in the route in the country not commercially available, and can be prepared before the experiment, the manufacturing process is more complex, more difficult to industrial production.

 

Skilled in the art knows the energy super low temperature chemical reaction operations is considerable. Generally, the reaction temperature at -40 ℃ over the operation of the more conventional reactor in the plant can be relatively easy to do; but lower than the reaction below -40 ℃ the need to use special equipment or a special reactor is required with liquid nitrogen as the cooling source, the higher the cost. For ultra-low temperature improvements often become enlarged or when the process of large-scale, process optimization of key points.

 

In the background art described in this article about the Ignatius column net three synthetic route, the “connection” between the main synthon mainly related to the organometallic reagents – such as organic lithium or magnesium organic lithium reagents protected hydroxy D- glucose ester carbonyl lactone on nucleophilic substitution reaction with hydroxyl groups to form the corresponding glucose derivative on the terminal carbon; then after hydroxy or derivatives thereof – methoxy reduced to hydrogen, to give the title with β-type hand glycoside bond Ignatius column net key intermediate structure; and finally the removal of hydroxy protecting groups on the pyranose ring to give Ignatius column net. In these types of synthetic route, operation and post-processing reaction steps are more complicated, the cost is high. For example, in Scheme 1 and 2, both the use of ultra-low temperature organolithium reagent – minus 78 ℃; several synthetic route in addition, most of the intermediate purification using column chromatography, such process is not suitable for plant production is amplified. Therefore, an urgent need to find new Ignatius column net synthesis method, and enables industrial production.

 

(1), from 4-fluoro-3- (2-benzothienyl) phenyl methyl halide (Compound 5) as a starting material, the compound 5 in a suitable solvent, is reacted with an alkyl lithium, followed by reaction with zinc an organic zinc reagent – bis [4-fluoro-3- (2-benzothienyl) methyl phenyl] zinc, and then with 2,3,4,6-tetra -O- pivaloyl bromo -α-D- Generation glucopyranose (compound 4) nucleophilic substitution reaction of intermediate net Ignatius column – compound 3;
(2), compound 3 by an organic base off pivaloyl protecting group to obtain Eagle column net (Compound 2);

 

Wherein in the 4-fluoro-3- (2-benzothienyl) phenyl methyl halide (Compound 5) Structure X is selected from bromo or iodo;

 

Synthetic route is as follows:

 

 

Example 1, (1S) -2,3,4,6- four -O- pivaloyl anhydro-1- [3- (1-thiophen-2-yl-methyl) -4 Preparation fluorophenyl] glucitol (compound 3) –
Zinc bromide (0.676 g) and lithium bromide (0.261 g) was added n-butyl ether (8mL), stirred and heated to 50 deg.] C 2h, cooling backup. Under nitrogen, was added 2- (5-iodo-2-fluorobenzyl) benzothiophene (2.21g) in toluene (5mL), n-butyl ether (5mL), cooled to -25 deg.] C, was slowly added dropwise 1.6mol / L n-hexyl lithium hexane solution (4.13 ml), to control the internal temperature does not exceed -10 deg.] C, after the addition was complete the reaction was incubated at -20 ℃ 0.5h, a solution of n-butyl ether was added to the backup lithium bromide and zinc bromide, at 10 ℃ reaction was stirred 3h. Was added 2,3,4,6-tetra -O- pivaloyl bromo -α-D- glucopyranose (3.48 g of) in toluene (10 mL) solution and heated to 80 deg.] C the reaction was stirred 6h, TLC analysis after completion of the reaction, was added 1mol / L dilute hydrochloric acid (7mL), water (20 mL), the combined organic phase was washed with water, dried over anhydrous of Na 2 the SO 4 dried, concentrated, and n-heptane (5mL) and methanol (15mL) recrystallized 3.452g 3 of solid compound, yield: 77.65%. Purity: 99.45%. Melting point: 128.9 ~ 130.5 ℃. 1 the H-NMR (CDCl 3 ): [delta] 7.72 (IH, D), 7.64 (IH, D), 7.21-7.30 (4H, m), 7.04 (IH, T), 6.96 (IH, S), 5.40 ( 1H, t), 5.27 (2H , m), 4.36 (1H, d), 4.08-4.21 (4H, m), 3.82 (1H, dd), 1.19 (9H, s), 1.16 (9H, s), 1.11 (9H, s), 0.85 ( 9H, s).
Example 2, (1S) -2,3,4,6- four -O- pivaloyl anhydro-1- [3- (1-thiophen-2-yl-methyl) -4 Preparation fluorophenyl] glucitol (compound 3) –
Zinc bromide (0.676 g) and lithium bromide (0.261 g) was added n-butyl ether (8mL), stirred and heated to 50 deg.] C 2h, cooling backup. Under nitrogen, was added 2- toluene (5mL) (5- iodo-2-fluorobenzyl) benzothiophene (2.21g) in n-butyl ether (5mL), cooled to – 50 ℃, was slowly added dropwise 2.5mol / L n-butyllithium hexane solution (2.64 mL), controlling the internal temperature does not exceed -30 deg.] C, 6h after the addition was complete the reaction was kept at -50 deg.] C, was added a solution of n-butyl ether in said auxiliary zinc bromide and lithium bromide, the reaction was stirred 8h at -20 ℃. Was added 2,3,4,6-tetra -O- pivaloyl bromo -α-D- glucopyranose (6.954g) in toluene (12mL) solution, heated to 25 deg.] C the reaction was stirred 24h, after completion of the reaction by TLC, was added 1mol / L dilute hydrochloric acid (8mL), water (20 mL), the combined organic phase was washed with water, dried over anhydrous of Na 2 the SO 4 dried, concentrated, and n-heptane (5mL) and methanol (15mL) recrystallized 3.237g 3 of solid compound, yield: 72.81%. Purity: 99.36%.
Example 3, (1S) -2,3,4,6- four -O- pivaloyl anhydro-1- [3- (1-thiophen-2-yl-methyl) -4 Preparation fluorophenyl] glucitol (compound 3) –
Zinc iodide (1.915g) and lithium iodide (0.803 g) in n-butyl ether was added (10mL), stirred and heated to 50 deg.] C 1.5h, cool reserve. Under nitrogen, was added 2- (5-iodo-2-fluorobenzyl) benzothiophene (2.21g) in toluene (9mL), n-butyl ether (3mL), cooled to -30 deg.] C, was slowly added dropwise 1.6mol / L n-hexyl lithium hexane solution (4.13mL), controlling the internal temperature does not exceed -20 ℃, n-butyl ether solution after the addition was complete the reaction was kept at -30 ℃ at 5h, zinc iodide was added to the backup and lithium iodide the mixture was stirred at 25 ℃ reaction 1h. After addition of 2,3,4,6-tetra -O- pivaloyl bromo -α-D- glucopyranose (4.346g) in toluene (10 mL) solution, the reaction was heated to reflux for 145 ℃ 0.5h, TLC detection completion of the reaction , was added 1mol / L dilute hydrochloric acid (8mL), water (20 mL), the combined organic phase was washed with water, dried over anhydrous of Na 2 the SO 4 dried, concentrated, and n-heptane (5mL) and methanol (15mL) recrystallized 3.552 3 g of a solid compound in a yield of 79.9%. Purity: 99.41%.
Example 4, (1S) -2,3,4,6- four -O- pivaloyl anhydro-1- [3- (1-thiophen-2-yl-methyl) -4 Preparation fluorophenyl] glucitol (compound 3) –
Zinc bromide (0.676 g) and lithium bromide (0.261 g) was added n-butyl ether (7mL), stirred and heated to 50 deg.] C 2h, cooling backup. Under nitrogen atmosphere, 2- (5-bromo-2-yl) benzothiophene (1.927g) was added toluene (6mL), n-butyl ether (4mL), cooled to -30 deg.] C, was slowly added dropwise 2.5mol / L n-butyllithium hexane solution (2.88 mL), controlling the internal temperature does not exceed -20 deg.] C, 3h after the addition was complete the reaction was kept at -30 deg.] C, was added a solution of n-butyl ether in said auxiliary zinc bromide and lithium bromide, the reaction was kept at -5 ℃ 4h, was added 2,3,4,6-tetra -O- pivaloyl bromo -α-D- glucopyranose (4.346g) in toluene (7mL) solution, stirred and heated to 120 ℃ The reaction 4h, after completion of the reaction by TLC, was added 1mol / L dilute hydrochloric acid (8mL), water (20 mL), the combined organic phase was washed with water, dried over anhydrous of Na 2 the SO 4 dried, and concentrated under reduced pressure, n-heptane (5mL ) and methanol (15mL) recrystallized 2.783g solid compound 3, yield: 62.6%. Purity: 99.29%.
EXAMPLE 5, (1S) -2,3,4,6- four -O- pivaloyl anhydro-1- [3- (1-thiophen-2-yl-methyl) -4 Preparation fluorophenyl] glucitol (compound 3) –
Zinc bromide (0.676 g) and lithium bromide (0.261 g) was added cyclopentyl ether (8mL), stirred and heated to 50 deg.] C 2h, cooling backup. Under nitrogen, was added 2- (5-iodo-2-fluorobenzyl) benzothiophene (2.21g) in toluene (6mL), cyclopentyl methyl ether (6mL), cooled to -30 deg.] C, was slowly added dropwise 1.6 mol / L hexane solution of n-hexyl lithium (4.5mL), controlling the internal temperature does not exceed -20 ℃, after the addition was complete the reaction was kept at -30 ℃ at 3h, added to the backup lithium bromide and zinc bromide cyclopentylmethyl the ether solution, the reaction incubated at -5 ℃ 4h, was added 2,3,4,6-tetra -O- pivaloyl bromo -α-D- glucopyranose (4.346g) in toluene (8mL) solution, heated to 120 ℃ reaction was stirred 4h, after completion of the reaction by TLC, was added 1mol / L dilute hydrochloric acid (8mL), water (20 mL), the combined organic phase was washed with water, dried over anhydrous of Na 2 the SO 4 dried, and concentrated under reduced pressure, with n-heptane dioxane (5mL) and methanol (15mL) recrystallized 2.088g solid compound 3, yield: 47%. Purity: 99.3%.
6, (1S) -2,3,4,6- four -O- pivaloyl anhydro-1- [3- (1-thiophen-2-yl-methyl) -4 Example Preparation fluorophenyl] glucitol (compound 3) –
Zinc bromide (0.676 g) and lithium bromide (0.261 g) was added methyl t-butyl ether (8mL), was heated to 50 ℃ stirred 3h, cooling backup. Under nitrogen, was added 2- toluene (6mL), methyl t-butyl ether (4mL) (5- iodo-2-fluorobenzyl) benzothiophene (2.21g), cooled to -40 deg.] C, was slowly added dropwise 1.6 mol / L n-hexyl lithium hexane solution (3.94mL), controlling the internal temperature does not exceed -30 ℃, after the addition was complete the reaction was kept at -40 ℃ at 4h, was added to the lithium bromide and zinc bromide spare methyl tert-butyl ether solution, the reaction incubated at 5 ℃ 7H, was added 2,3,4,6-tetra -O- pivaloyl bromo -α-D- glucopyranose (3.48 g of) in toluene (8mL) solution, heated to 90 ℃ reaction was stirred 6h, after completion of the reaction by TLC, was added 1mol / L dilute hydrochloric acid (8mL), water (20 mL), the combined organic phase was washed with water, dried over anhydrous of Na 2 the SO 4 dried, and concentrated under reduced pressure, with n-heptane dioxane (5mL) and methanol (15mL) recrystallized 2.792g solid compound 3, yield: 62.8%. Purity: 99.44%.
Example 7, (1S) -1,5- anhydro-1- [3- (1-methyl-thiophen-2-yl) -4-fluorophenyl] -D-glucitol (Compound 2) preparation
Compound 3 (7.41g) was added methanol (35mL), was added sodium methoxide (2.161g), heated at reflux for 5H reaction, after completion of the reaction by TLC, concentrated and the residue was added methanol (10 mL), water (10 mL), acetic acid ( 3g), was added seed crystal (0.1g), stirred at 5 ℃ crystallization, filtration, the filter cake washed with cold (methanol: (5mL) was washed with 1) solvent to give an off-white solid 3.89g compound 2: water = 1 , yield: 96.2%. Purity: 99.29%. 1 the H-NMR (the CD 3 the OD): [delta] 7.70 (IH, D), 7.63 (IH, D), 7.43 (IH, dd), 7.34-7.38 (IH, m), 7.21-7.26 (2H, m) , 7.08 (1H, t), 7.01 (1H, s), 4.18-4.28 (2H, m), 4.12 (1H, d), 3.88 (1H, dd), 3.70 (1H, dd), 3.30-3.50 (4H , m).
Example 8, (1S) -1,5- anhydro-1- [3- (1-methyl-thiophen-2-yl) -4-fluorophenyl] -D-glucitol (Compound 2) preparatio
Methanol was added (15mL) of the compound 3 (7.41g) was added sodium hydroxide (2g) in water (10 mL) solution was heated to 50 deg.] C the reaction was stirred 10h, TLC detection after completion of the reaction, water (10mL), 2mol / L hydrochloric acid (2mL), stirred at room temperature for crystallization, white solid was suction filtered, the filter cake washed with water (5mL) was washed and dried to give 3.806g of compound 2, yield: 94.1%. Purity: 99.31%.
Preparation 9, Ignatius column eutectic net L- proline (Compound 1) Example
Net Ignatius column (compound 2) (4.04g) was added ethanol (25mL), was added L- proline (1.15 g of), the reaction was heated at reflux for 1h, cooled to room temperature, filtered, the filter cake washed with cold ethanol, and dried to give white solid 4.67g of compound 1. Yield: 90%. Purity: 99.51%. Melting point: 194.0 ~ 202.1 ℃. The MS-ESI (m / Z): 427.16 [the M + of Na] + . 1 the H-NMR (the CD 3 the OD): [delta] 7.75 (IH, D), 7.67 (IH, D), 7.45 (IH, dd), 7.37 (IH, m), 7.24-7.31 (2H, m), 7.10 (1H, t), 7.07 ( 1H, s), 4.23-4.32 (2H, m), 4.13 (1H, d), 3.98 (1H, t), 3.89 (1H, d), 3.71 (1H, dd),3.31-3.50 (5H, m), 3.21-3.27 (1H, m), 2.27-2.34 (1H, m), 2.09-2.17 (1H, m), 1.95-2.02 (2H, m).

Claims

Ignatius one kind of column and net synthesis process, comprising the steps of: (1), from 4-fluoro-3- (2-benzothienyl) methyl-5-phenyl-halide as a raw material, in an appropriate solvent 5 is reacted with an alkyl lithium, followed by reaction with the zinc salt prepared organozinc reagents – bis [4-fluoro-3- (2-benzothienyl) methyl phenyl] zinc, and then with 2,3,4,6-tetra -O- pivaloyl -α-D- glucopyranose 4-bromo nucleophilic substitution reaction of intermediate net Ignatius column 3; (2), compound 3 by an organic base off pivaloyl protecting group prepared net Ignatius column 2; wherein, in the 4-fluoro-3- (2-benzothienyl) methyl-5-phenyl halide of structure X is selected from bromo or iodo; synthesis route is as follows:

////////WO 2016173551, China State Institute of Pharmaceutical Industry; Shanghai Institute of Pharmaceutical Industry, IPRAGLIFLOZIN, NEW PATENT,

Sacubitril, WO 2016180275, New patent, SUZHOU PENGXU PHARMATECH CO., LTD


Sacubitril, WO 2016180275, New patent, SUZHOU PENGXU PHARMATECH CO., LTD

AHU-377 INTERMEDIATES AND METHOD FOR PREPARING AHU-377 AND AHU-377 INTERMEDIATES PATENT

WO2016180275, new patent, SUZHOU PENGXU PHARMATECH CO., LTD. [CN/CN]; 3rd Floor Building 7, 2358 Chang An Road, Wujiang Suzhou, Jiangsu 215200 (CN)

WANG, Peng; (CN).

LI, Pixu; (CN).

GU, Xiangyong; (CN)

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Heart failure is a very high mortality syndrome, for patients with heart failure, so far no drug can significantly improve mortality and morbidity, and thus a new type of therapy is necessary. AHU-377 (CAS No. 149709-62-6) is an enkephalinase inhibitor, which is a prodrug ester groups can be lost through hydrolysis, converted to pharmaceutically active LBQ657, inhibit endorphin enzyme (NEP) the role of the main biological effects of NEP is to natriuretic peptides, bradykinin and other vasoactive peptide degradation failure. AHU-377 and angiotensin valsartan composition according to the molar ratio of 1 LCZ696. LCZ696 is an angiotensin receptor enkephalinase inhibitors, which can lower blood pressure, treat heart failure may become a new drug. Clinical data show, LCZ696 is more effective for the treatment of hypertension than valsartan alone.

Patents US 5,217,996 and US 5,354,892 reported the first synthesis of AHU-377, the synthetic route is as follows:

 

 

Reaction with unnatural D-tyrosine derivative as a substrate, more expensive, while the second step in the synthesis is necessary to use Pd-catalyzed Suzuki coupling reaction, whereby preparative route costs than the AHU-377 high.

 

Patent US 8,115,016 above routes also reported the departure from the pyroglutamate, through multi-step process for preparing a reaction AHU-377, which is more difficult methylation reaction, and the yield is not high. Patent US 8,580,974 also reported a carbonyl group of the a- introducing N, N- dimethyl enamine is converted to methyl, however, there are some problems in the route for constructing methyl chiral centers, are not suitable for scale-up synthesis route as follows:

 

 

About the latest AHU377 synthesis intermediates, Patent WO2014032627A1 reported using a Grignard reagent to react with epichlorohydrin, a quicker been important intermediates, synthetic route Compound AHU377 synthesized as follows:

However, the second step of the synthetic route use succinimide nitrogen atoms introduced by Mitsunobu reaction with hydrochloric acid hydrolysis to remove, then converted to Boc protected at the end of the synthesis process AHU377 Boc will have to take off protection, then any connection with succinic anhydride reaction product introduced into the structure of succinic acid portion, so that this method of atom economy and the economy of the steps are low.

 

Example 1

 

Synthesis of Compound 2

 

 

In inert atmosphere, a solution of three 500mL flask was added compound 1 (10g, 1eq), dissolved after 90mL THF, was added CuI (4.814g, 0.1eq), the system moves to the low temperature in the cooling bath to -20 ℃ when, biphenyl magnesium bromide dropwise addition, the internal temperature was controlled not higher than -10 ℃. Bi closed refrigeration drop, return to room temperature overnight. Completion of the reaction, the reaction solution was poured into saturated the NH 4 of Cl (10vol, 100 mL) was stirred at room temperature for 0.5h. Suction filtered, the filter cake was rinsed with a small amount of EA, and the filtrate was transferred to a separatory funnel carved, and the aqueous phase was extracted with EA (10vol × 2,100mL × 2) and the combined organic phases with saturated NaHC [theta] 3 , the NH 4 of Cl, each Brine 150mL (15vol) washed once, dried over anhydrous over MgSO 4 dried, suction filtered, and concentrated to give a white solid. Product obtained was purified by column 15.2g, yield 78%.

 

NMR data for the product are as follows:

1 the H NMR (400MHz, CDCl 3 ) [delta] 7.57 (D, J = 7.6Hz, 2H), 7.52 (D, J = 8.1Hz, 2H), 7.42 (T, J = 7.6Hz, 2H), 7.38-7.25 (m, 8H), 4.62-4.47 ( m, 2H), 4.09 (dd, J = 6.7,3.5Hz, 1H), 3.54 (dd, J = 9.5,3.5Hz, 1H), 3.43 (dd, J = 9.4 , 6.9Hz, 1H), 2.84 ( d, J = 6.6Hz, 2H), 2.38 (s, 1H).

 

Example 2

 

Synthesis of Compound 3

 

 

In an inert gas, at room temperature was added to the flask 500mL three Ph3P (18.54g, 2eq), 240mL DCM dissolution, butyryl diimide (of 6.44 g), compound 2 (15g), an ice-water bath cooling to 0 ℃ or so, was added dropwise DIAD (14mL) was complete, the reaction go to room temperature.Starting material the reaction was complete, the system was added to water (100 mL) quenched the reaction was stirred for 10min; liquid separation, the aqueous phase was extracted with DCM (100mL × 2), the combined organic phases with saturated Brine 100mL × 2), dried over anhydrous over MgSO 4 dried , filtration, spin dry to give a white solid; product was purified by column 15.4g, yield 82%.

 

NMR data for the product are as follows:

 

1 the H NMR (400MHz, CDCl 3 ) [delta] 7.56 (D, J = 7.4Hz, 2H), 7.49 (D, J = 8.0Hz, 2H), 7.42 (T, J = 7.6Hz, 2H), 7.37-7.30 (m, 3H), 7.27 ( d, J = 6.7Hz, 3H), 7.22 (d, J = 8.0Hz, 2H), 4.75 (s, 1H), 4.56 (d, J = 12.0Hz, 1H), 4.45 (d, J = 12.0Hz, 1H ), 4.06 (t, J = 9.6Hz, 1H), 3.70 (dd, J = 10.0,5.2Hz, 1H), 3.23 (dd, J = 13.8,10.3Hz, 1H) , 3.14-3.00 (m, 1H), 2.48 (d, J = 4.0Hz.4H).

 

Example 3

 

Synthesis of Compound 4

 

 

Protection of inert gas, at room temperature was added to the flask 1L three compound 3 (18.81g), 470mL EtOH was dissolved, was added Pd / C, replaced the H 2 three times, move heated on an oil bath at 60 ℃ reaction. Raw reaction was complete, the system was removed from the oil bath, the reaction solution was suction filtered through Celite and concentrated to give the crude product. It was purified by column pure 11.8g, a yield of 81.2%.

 

NMR data for the product are as follows:

 

1 the H NMR (400MHz, CDCl 3 ) [delta] 7.57 (D, J = 7.8Hz, 2H), 7.51 (D, J = 7.8Hz, 2H), 7.42 (T, J = 7.5Hz, 2H), 7.33 (T , J = 7.2Hz, 1H), 7.26 (d, J = 7.2Hz, 2H), 4.55 (d, J = 5.2Hz, 1H), 4.06-3.97 (m, 1H), 3.86 (dd, J = 12.0, 3.1Hz, 1H), 3.16 (dd , J = 8.1,2.9Hz, 2H), 2.58 (t, J = 7.0Hz, 4H), 1.26 (s, 2H).

Example 4

 

Synthesis of Compound 7

 

Protection of inert gas, at room temperature to a 25mL flask was added three Dess-Martin oxidant (767.7mg), 10mL DCM was dissolved, the system was cooled down to -10 deg.] C, was added 4 (500mg). Starting material the reaction was complete, to the system was added saturated NaHCO3 and Na2S2O3 each 5mL, quench the reaction stirred for 10min; aqueous phase was extracted with DCM (10mL × 3) and the combined organic phases with saturated NaHCO3, Brine 30mL each wash, dried over anhydrous MgSO4, filtration, spin dried to give the crude product used directly in the next reaction cast.

Example 5

 

Synthesis of Compound 8

Inert gas, at room temperature for three to 500mL flask 7 (497.5mg), 10mL DCM to dissolve an ice water bath to cool, added phosphorus ylide reagent (880.6mg), the system was removed from the ice water bath at room temperature. The reaction material completely stop the reaction, the system was added to water (5mL) to quench the reaction. Liquid separation, the aqueous phase was extracted with DCM (10mL × 2), organic phases were combined, washed with saturated Brine 20mL × 2, dried over anhydrous MgSO4, filtration, spin crude done. Product obtained was purified by column 563mg, 90% yield.

 

NMR data for the product are as follows:

 

1 the H NMR (400MHz, CDCl 3 ) δ7.60-7.53 (m, 2H), 7.51 (D, J = 8.1Hz, 2H), 7.42 (T, J = 7.6Hz, 2H), 7.33 (D, J = 7.3Hz, 1H), 7.23 (d , J = 8.1Hz, 2H), 7.13 (dd, J = 9.2,1.5Hz, 1H), 5.26 (td, J = 9.5,6.9Hz, 1H), 4.25-4.05 ( m, 2H), 3.40 (dd , J = 13.7,9.7Hz, 1H), 3.13 (dd, J = 13.8,6.7Hz, 1H), 2.53 (d, J = 2.2Hz, 4H), 1.85 (d, J = 1.4Hz, 3H), 1.30 ( t, J = 7.1Hz, 3H).

Example 6

 

Synthesis of Compound 9

 

Protection of inert gas, at room temperature to a 50mL flask was added three 8 (365mg, 1eq), 9mL of ethanol and stirred to dissolve, the system was replaced with hydrogen three times, was added Pd / C (25% w / w) at room temperature. The reaction material completely stop the reaction, the system was added to water (5mL) to quench the reaction. The reaction mixture was suction filtered through Celite and concentrated to give the crude product. Product was purified by column, yield 80.2%, purity 97.2%.

Example 7

 

Synthesis of Compound 10

Equipped with Compound 9 (100mg) acetic acid A reaction flask (9mL), hydrochloric acid (1mL). The reaction was heated oil bath at 80 deg.] C. The reaction material completely stop the reaction, the system was added to water (5mL) to quench the reaction. After saturated NaHCO3 and extracted with EA and concentrated to give crude product. Product obtained was purified by column 90mg, yield 84%.

 

NMR data for the product are as follows:

 

1 the H NMR (400MHz, CDCl 3 ) δ7.61-7.54 (m, 2H), 7.53-7.48 (m, 2H), 7.41 (dd, J = 10.5,4.9Hz, 2H), 7.31 (dd, J = 8.3 , 6.4Hz, 1H), 7.22 ( d, J = 8.2Hz, 2H), 5.93 (t, J = 9.7Hz, 1H), 4.34-4.00 (m, 3H), 2.91-2.71 (m, 2H), 2.68 -2.57 (m, 2H), 2.55 (ddd, J = 9.4,7.0,4.3Hz, 1H), 2.42 (dt, J = 13.3,6.8Hz, 2H), 1.97-1.74 (m, 1H), 1.64-1.46 (m, 1H), 1.23 ( td, J = 7.1,3.3Hz, 3H), 1.14 (dd, J = 7.1,3.9Hz, 3H)

Example 8

Synthesis of Compound 5

 

 

Example 8-1: The reaction flask was added compound 4 (1eq) was added water (2VOL), concentrated hydrochloric acid (2VOL), 110 ℃ reaction was heated in an oil bath overnight, complete conversion of starting material, the HPLC peak area 97%. 10% NaOH solution was added to adjust the pH to about 10, filtration products. Yield 85%.

 

Example 8-2: The reaction flask was added compound 4 (1eq) was added ethanol (5 vol), water (5 vol), potassium hydroxide (8 eq), was heated in an oil bath overnight at 110 ℃ reaction, complete conversion of the starting material, the HPLC peak area 99%. Water was added (5Vol), filtered to obtain the product. Yield 95%. Product was dissolved in toluene, was added ethanolic hydrochloric acid, the precipitated hydrochloride Compound 5.

NMR data for the product are as follows:

 

1 the H NMR (400MHz, of DMSO) [delta] 8.31 (S, 3H), 7.70-7.61 (m, 4H), 7.47 (T, J = 7.6Hz, 2H), 7.42-7.31 (m, 3H), 4.09 (the dq- , J = 42.6,7.1Hz, 1H), 3.62-3.51 (m, 1H), 3.50-3.41 (m, 1H), 3.11-3.00 (m, 1H), 2.95-2.84 (m, 1H), 1.30-1.10 (m, 1H).

 

EXAMPLE 9

Synthesis of Compound 6

 

To the reactor was added compound 5, was added absolute ethanol (3vol). Temperature of the outer set 30 ℃ heating, stirring was continued after the temperature reached 25 ℃ 20min. Was added 30% NaOH aqueous solution (1.1eq). External temperature 65 ℃ heating provided, after the internal temperature reached 60 deg.] C was slowly added (of Boc) 2 O (1.1 eq). Stirring 0.5h, reaction monitoring. After completion of the reaction, water was added slowly dropwise (8vol), turn off the heating and natural cooling. The system temperature was lowered to 25 deg.] C and continue stirring for 2h. Filter cake at 50 ℃ blast oven drying to obtain the product.

 

NMR data of the product are as follows:

 

1 the H NMR (400MHz, CDCl 3 ) δ7.61-7.50 (m, 4H), 7.61-7.50 (m, 4H), 7.46-7.39 (m, 2H), 7.48-7.38 (m, 2H), 7.38-7.23 (m, 3H), 7.37-7.26 ( m, 3H), 4.82 (d, J = 7.9Hz, 1H), 4.82 (d, J = 7.9Hz, 1H), 3.91 (s, 1H), 3.70 (d, J = 11.0Hz, 1H), 3.77-3.54 (m, 2H), 3.65-3.47 (m, 1H), 2.88 (d, J = 7.0Hz, 2H), 2.88 (d, J = 7.0Hz, 2H), 2.51 (s, 1H), 2.51 (s, 1H), 1.42 (s, 9H), 1.42 (s, 9H).

 

Synthesis of Intermediate Compound 6 to Compound 10, i.e., the AHU-377, a synthetic route in the background of the present invention, the cited patent application WO2014032627A1 loaded in detail, not in this repeat.

 

Example 10

Synthesis of Compound 2

 

 

Benzyl glycidyl ether preparation (50g) in THF (200mL) was added. Under inert gas protection, the biphenyl magnesium bromide (365mmol) was added to THF (1020mL) was added the reaction flask is placed in a low temperature bath -40 ℃ cooling. Cuprous iodide (O.leq) when the internal temperature dropped to -9 ℃. Continued to decrease the temperature of -23 ℃ dropwise addition of benzyl glycidyl ether in THF was added dropwise to control the internal temperature process of not higher than -15 deg.] C, 47 min when used, the addition was completed the cooling off the reaction was stirred overnight. The cooling system to -20 ℃ quenched with 1N HCl aqueous solution, <10 ℃ Go stirred 30min at room temperature. Liquid separation, the aqueous phase was extracted with THF, the combined THF phases. Respectively saturated ammonium chloride (250mL), saturated brine (250mL) washed. Rotary evaporation to remove THF, and water (200 mL) Continue rotary evaporation 1h, cool to precipitate a solid. Suction crude. Crude n-heptane was added 2Vol beating, suction filtration to obtain the product in a yield of 90 ~ 95%, HPLC peak area 94%. In another column purification was pure, columned yield 88.6%, HPLC 99.1%.

 

Example 11

 

Synthesis of Compound 3

 

Preparation Example 9, said compound taking the embodiment 2 (5g) added to the reaction flask, the reaction flask was added toluene (80mL), phthalimide (2.55 g of) and triphenylphosphine (5.35g of), the nitrogen was replaced protection. An ice-salt bath cooling to -5 deg.] C, was added dropwise DIAD (4.12g), dropwise addition was exothermic, the temperature was raised to 5 ℃. The reaction was continued 1h sampling HPLC test material substantially complete reaction. Join 12g silica spin column done to collect the product (including DIEA derivative).

 

Example 12

Synthesis of Compound 11

 

 

Compound 3 (3g) was added to the reaction flask embodiment taken in Preparation Example 10, was added ethanol (30 mL), with stirring. Was added hydrazine hydrate (2g) was heated in an oil bath reflux 1h, when supplemented with 20mL ethanol was stirred difficulties, the reaction was continued to 2.5h, HPLC showed the starting material the reaction was complete. Add EA / H2O 100mL each liquid separation, the EA phase was washed with water (100mL) and the combined organic phases were washed with water (100mL) and saturated brine (100mL) washed. Anhydrous magnesium sulfate and filtered spin column was done product 1.88g, yield 88%, HPLC 94%.

 

NMR data of the product are as follows:

 

1 the H NMR (400MHz, of DMSO) [delta] 7.64 (D, J = 7.2Hz, 2H), 7.57 (D, J = 8.1Hz, 2H), 7.45 (T, J = 7.6Hz, 2H), 7.39-7.32 ( m, 5H), 7.29 (d , J = 8.1Hz, 3H), 4.55-4.43 (m, 2H), 3.38-3.23 (m, 3H), 3.18-3.10 (m, 1H), 2.82-2.74 (m, 1H), 2.61-2.52 (m, 1H ).

 

Example 13

 

Synthesis of Compound 11

 

To the toluene solution of the compound 2 was added phthalimide (1.1 eq), triphenylphosphine (1.3 eq) with stirring. External bath set -10 ℃, to cool the system, the internal temperature dropped to 0 ~ 5 ℃, start dropping DIAD (1.3eq), control the internal temperature -5 ~ 5 ℃. Completion of the dropwise addition, the cooling bath was turned off outside the reaction was stirred at room temperature. The reaction was stirred for 1 to 4 hours. The reaction solution to give compound 3, administered directly in the next reaction. To the above reaction mixture was added hydrazine hydrate (6 eq), heated to 70 ~ 80 ℃, to complete the reaction, filtered hot, the filtrate. Aqueous sodium hydroxide solution (20vol 10%) was stirred for 0.5h, allowed to stand for liquid separation from toluene phase. Water was added (20vol) was stirred for 0.5h, allowed to stand for liquid separation from toluene phase. The toluene phase was added hydrochloric acid (20vol, 3N), stirred for 0.5h, to form a solid precipitate. Filtration and drying to obtain a product, i.e. compound 11, the hydrochloride salt, yield 60% in two steps.

NMR data of the product are as follows:

 

1 the H NMR (400MHz, of DMSO) [delta] 8.46 (S, 3H), 7.63 (dd, J = 16.4,7.7Hz, 4H), 7.47 (T, J = 7.6Hz, 2H), 7.42-7.22 (m, 8H ), 4.56 (d, J = 12.1Hz, 1H), 4.48 (d, J = 12.1Hz, 1H), 3.58 (d, J = 7.9Hz, 2H), 3.47 (dd, J = 10.9,6.3Hz, 1H ), 3.11 (dd, J = 13.5,4.9Hz, 1H), 2.92 (dd, J = 13.4,9.1Hz, 1H).

Example 14

 

Synthesis of Compound 12

 

 

Weigh Compound 11 (1.38g) was added to the reaction flask. To the reaction flask plus DCM (14ml) and Et3N (462mg, 0.73ml). Weighed (of Boc) 2O (1.23 g of) was added to DCM (5ml) was dissolved. Room temperature (8 ℃), a solution (of Boc) 2 DCM solution O was added dropwise to the reaction, (2ml) rinsed with DCM. The reaction mixture was stirred at room temperature, detected by HPLC, the reaction ends 4h. Reaction mixture was washed (15ml) 3 times with Brine (15ml) The reaction solution was washed 1 times. Inorganic sulfate, concentrated and purified by column PE:EA = 15:1 give product 560mg, yield 30.8%, HPLC 99.92%.

NMR data of the product are as follows:

1 the H NMR (400MHz, CDCl 3 ) [delta] 7.57 (D, J = 7.6Hz, 2H), 7.49 (D, J = 7.4Hz, 2H), 7.43 (T, J = 7.3Hz, 2H), 7.39-7.28 (m, 5H), 7.24 ( d, J = 9.0Hz, 3H), 5.00-4.80 (br, 1H), 4.51 (q, J = 11.8Hz, 2H), 4.08-3.85 (br, 1H), 3.43 ( d, J = 2.9Hz, 2H) , 3.02-2.77 (m, 2H), 1.42 (s, 9H).

Example 15

Synthesis of Compound 6

 

 

Weigh Compound 12 (250mg) and methanol (9ml) was added to the reaction flask. Added Pd / C (138mg, 1 / 4w / w, water content 55%). The H 2replaced 3 times, 50 ℃ stirred and heated. HPLC detection reaction, the reaction end 30h. Filtered off Pd / C, 40 ℃ concentrated under reduced pressure to remove methanol. PE:EA = 3:1 florisil column to give the product 196mg, 100% yield, 99.34% purity.

 

NMR data of the product are as follows:

 

1 the H NMR (400MHz, CDCl 3 ) δ7.61-7.50 (m, 4H), 7.61-7.50 (m, 4H), 7.46-7.39 (m, 2H), 7.48-7.38 (m, 2H), 7.38-7.23 (m, 3H), 7.37-7.26 ( m, 3H), 4.82 (d, J = 7.9Hz, 1H), 4.82 (d, J = 7.9Hz, 1H), 3.91 (s, 1H), 3.70 (d, J = 11.0Hz, 1H), 3.77-3.54 (m, 2H), 3.65-3.47 (m, 1H), 2.88 (d, J = 7.0Hz, 2H), 2.88 (d, J = 7.0Hz, 2H), 2.51 (s, 1H), 2.51 (s, 1H), 1.42 (s, 9H), 1.42 (s, 9H).

 

Method for preparing the AHU-377, characterized by comprising the steps of: (a) Compound (1) S- benzyl glycidyl ether and biphenyl Grignard reagent produced by the reaction of the compound (2) in an organic solvent; ( b) compound (2) with a succinimide or phthalimide Mitsunobu reaction occurs in an organic solvent to form a compound (3); (C) compound (3) in an organic solvent in the role of a catalyst under removal debenzylation protected form compound (4); (D) compound (4) with an oxidizing agent oxidation reaction occurs in an organic solvent to form a compound (7); (E) compound (7) with a phosphorus ylide reagent in an organic solvent to give the compound (8); (F.) compound (8) in an organic solvent in the selective catalytic hydrogenation of the compound (9); and (g) of the compound (9) in an organic solvent in the hydrolysis reaction of the amide compound occurs in the presence of an acid ( 10), i.e., AHU-377;

SUVEN LIFE SCIENCES LTD, WO 2016178064, POLYMORPH OF NINTEDANIB ETHANESULPHONATE, NEW PATENT


NINTEDANIB ETHANESULPHONATE

NEW PATENT

WO2016178064, CLICK FOR PATENT

POLYMORPH OF NINTEDANIB ETHANESULPHONATE, PROCESSES AND INTERMEDIATES THEREOF

SUVEN LIFE SCIENCES LIMITED [IN/IN]; 5th floor, Serene Chamber, Road No.5, Off Avenue No. 7, Banjara Hills, Telangana Hyderabad 500034 (IN)

ARAVA, Veera Reddy; (IN).
GOGIREDDY, Surendra Reddy; (IN).
JASTI, Venkateswarlu; (IN)

DR VEERA ARAVA REDDY

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Veerareddy Arava

Vice President

Surendra Reddy Gogireddy, Sr.Research Associate

JASTI, Venkateswarlu

The present invention provides novel crystalline Form of Nintedanib and process for its preparation. The present invention also provides to a novel process for the preparation of Nintedanib. The present invention further provides to novel intermediates used in the preparation of Nintedanib and process for their preparation.

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Nintedanib inhibits multiple receptor tyrosine kinases (RTKs) and non-receptor tyrosine kinases (nRTKs).The chemical name of Nintedanib is lH-Indole-6-carboxylic acid, 2,3-dihydro-3-[[[4-[methyl-(4-methyl-l-iperazinyl)acetyl]amino]phenyl]amino]phenylmethylene] -2-oxo-,methylester, (3Z)-, ethanesulfonate (1 : 1) and is structurally represented by compound of Formula I.

Formula I

Nintedanib is marketed in the United States under the trade name OFEV and is indicated for the treatment of Idiopathic Pulmonary Fibrosis (IPF).

Nintedanib was first described and claimed in U.S. Pat.No. 6,762, 180 and EP 1224 170. These patents disclose a process for the preparation of Nintedanib as depicted in scheme I given below:

U.S.Pat.No. 8,067,617 discloses a process for the preparation of Nintedanib intermediate Enolindole derivative), which is shown in the scheme-II given below:

Scheme-II

U.S.Pat. No. 7,119,093 discloses Nintedanib monoethanesulphonate in crystalline form characterised by X-ray powder diffraction pattern having 2Θ values at 7.70, 8.78, 9.47, 9.82, 11.59, 11.93, 13.15, 13.69, 14.17, 16.32, 16.72, 16.92, 17.43, 17.77, 18.58, 18.81, 19.03, 19.73, 19.87, 20.03, 20.61, 20.83, 21.26, 21.76, 22.05, 22.19, 22.57, 23.10, 23.81, 24.69, 24.78, 24.91, 25.42, 26.24, 26.91, 27.19, 27.61, 27.95, 28.71, 29.25.

Polymorphism, the occurrence of different crystal forms, is a property of some molecules and molecular complexes. A single molecule may give rise to a variety of polymorphs having distinct crystal structures and physical properties like melting point, X-ray diffraction pattern, infrared absorption fingerprint and solid state NMR spectrum. One polymorph may give rise to thermal behaviour different from that of another polymorph. Thermal behaviour can be measured in the laboratory by such techniques as capillary melting point, thermo gravimetric analysis (“TGA”) and differential scanning calorimetry (“DSC”), which have been used to distinguish polymorphic forms.

The differences in the physical properties of different polymorphs results from the orientation and intermolecular interactions of adjacent molecules or complexes in the bulk solid. Accordingly, polymorphs are distinct solids sharing the same molecular Formula yet having distinct advantageous physical properties compared to other polymorphs of the same composition or complex. Hence there remains a need for polymorphic forms which have properties suitable for pharmaceutical processing on a commercial scale.

Considering the importance of Nintedanib, there exists a need to develop an alternate and improved process for the preparation of Nintedanib with better yield. Further, the process involved should be simple, convenient and cost-effective for large scale production. The inventors of the present invention during their continuous efforts also developed a novel high melting stable polymorphic form of Nintedanib ethanesulfonate.

EXAMPLES

Example 1: Process for the preparation of Nintedanib Monoethane Sulfonate:

Step-1: Preparation of methyl-3-(hydroxy(phenyl)methylene)-2-oxoindoline-6-carboxylate: To the suspension of methyl 2-oxoindoline-6-carboxylate (50 gm, 0.261 mol) in IPA (350 ml) was added slowly SMO-powder (33.8 gm, 0.626 mol) and stirred for about 15 min. Benzyl chloride (44 g, 0.313 mol) was added after completion of the reaction at a reaction temperature of -5 to -10°C for about 5hrs. The reaction mixture was quenched into ice-water (700 ml) and acidified with Cone. HC1 (2.0-2.5 ml). Filtered the reaction mixture, washed with water (2X100 ml) and dried the precipitate to obtain crude product which can be recrystallized from acetonitrile (28 ml) to obtain methyl-3-(hydroxy(phenyl)methylene)-2- oxoindoline-6-carboxylate pure crystalline solid (32 gm) (61%) (HPLC purity >97%). The filtrate was evaporated in vacuum to give unreacted methyl 2-oxoindoline-6-carboxylate. MR: 216-223°C; IR (KBr, cm“1): 3178, 1711, 1651; 1H-NMR (400 MHz, DMSO): δ 3.80 (s, 3H), 7.17 (s, 1H), 7.28-7.31 (m, 2H), 7.46-7.50 (m, 3H), 7.72 (d, 2H, J = 6.0 Hz), 9.52 (s, 1H), 11.53 (s, 1H); 13C-NMR (100 MHz, DMSO): δ 22.12, 52.41, 101.13, 111.13, 119.23, 123.06, 126.65, 127.06, 128.65, 129.21, 132.26, 134.47, 136.99, 166.58, 172.52 and 175.80; MS: m/z 294 [M]“1

Step-2: Preparation of methyl-3-(acetoxy(phenyl)methylene)-l-acetyl-2-oxoindoline-6-carboxylate (Acetyl derivative):

To the suspension of methyl-3-(hydroxy(phenyl)methylene)-2-oxoindoline-6-carboxylate (45 gm, 0.1512 mol) in acetic anhydride (300 ml) was added pyridine (4.5g) slowly (drop-wise) and stirred the reaction at temperature of 0-5°C for about30 min. After completion of the reaction raised the temperature of the reaction mass to 75-80°C and stirred for about lhr. Cooled the reaction mass and stirred for about 30 min at 25-28°C, filtered, washed with hexane (100ml) and dried the precipitate to obtain methyl-3-(acetoxy(phenyl)methylene)-l-acetyl-2-oxoindoline-6-carboxylate.

MR: 226-229°C; IR (KBr, cm“1): 3413, 1771, 1743, 1717, 1640; 1H-NMR (400 MHz, CDC13): δ 2.38 (s, 3H), 2.62 (s, 3H), 3.92 (s, 3H), 7.44 (m, 3H), 7.62 (d, 2H, J = 7.004 Hz), 7.68 (d, 1H, J = 8.12 Hz), 7.91 (d, 1H, J = 8.0 Hz), 8.90 (s, 1H); 13C-NMR (100 MHz, CDC13): δ 21.08, 21.38, 26.96, 52.25, 52.34, 115.17, 117.18, 121.33, 122.77, 125.82, 126.19, 126.56, 128.15, 128.87, 129.27, 129.34, 130.81, 130.90, 131.47, 131.82, 132.80, 138.55, 160.85, 165.95, 166.38, 166.42, 167.01, 170.67 and 170.76; MS: m/z 380 [M]+1.

Step-3: Preparation of methyl- l-acetyl-3-(((4-(2-chloro-N-methylacetamido)phenyl)amino) (phenyl)methylene)-2-oxoindoline-6-carboxylate) (Chloroacetyl derivative) :

Suspension of methyl-3-(acetoxy(phenyl)methylene)- l-acetyl-2-oxoindoline-6-carboxylate (Acetyl derivative) (49gm, 0.129mol) and N-(4-aminophenyl)-2-chloro-N-methylacetamide(25.66gm, 0.129 mol) in a mixture of methanol (350 ml) and DMF (88 ml) was heated to 60-65°C stirred for about 12hr at the same temperature. After completion of the reaction cooled the reaction mass to room temperature and stirred for about 30min. Filtered the reaction mixture, washed with methanol (2X50ml) and dried the precipitate to obtainmethyl-l-acetyl-3-(((4-(2-chloro-N-ethylacetamido)phenyl)amino)(phenyl)methylene)-2-oxoindoline-6-carboxylate).

MR: 247-250°C; IR (KBr, cm“1): 3432, 1712, 1675, 1591; 1H-NMR (400 MHz, DMSO): δ 2.74 (s, 3H), 3.11 (s, 3H), 3.78(s, 3H), 3.87 (s, 2H), 5.75 (d, 1H, J = 8.08 Hz), 7.01 (d, 2H, J = 7.96 Hz), 7.22 (d, 2H, J = 6.08Hz), 7.36 (d, 1H, J = 8.48 Hz), 7.46 (d, 2H, J = 7.24 Hz), 7.54-7.64 (m, 3H), 8.74 (s, 1H0, 11.92 (s, 1H), 13C-NMR (100MHz, DMSO): δ 27.17, 37.76, 42.48, 52.40, 96.38, 116.17, 117.59, 124.80, 125.33, 125.68, 128.09, 129.00, 130.10, 131.35, 131.97, 134.05, 160.93, 165.63, 166.68, 168.49 and 171.28; MS: m/z 518 [M]+1 and 520 [M]+1.

Step-4: Preparation of (Z)-methyl-3-(((4-(N-methyl-2-(4-methylpiperazin-lyl)acetamide) phenyl) amino)(phenyl)methylene)-2-oxoindoline-6-carboxylate (Nintedanib free base):

Suspension of methyl- l-acetyl-3-(((4-(2-chloro-N-methylacetamido)phenyl)amino) (phenyl)methylene)-2-oxoindoline-6-carboxylate)(40 gm, 0.077ml) and N-methylpiperidine (23.24 gm, 0.232 mol) in a mixture of DMF (160 ml) was heated to a reaction temperature of 45-50°C for about l-2hrs. The reaction mixture was quenched into ice-water (1.6 Lt) and stirred for about lhr at 15-20°C. Filtered the reaction mixture mass washed with water and dried the precipitate to obtain crystalline crude solid (36 gm). Purified with acetonitrile to obtain Nintedanib free base (34 gm) as a yellow crystals (93.74%) (HPLC purity: >98%). MR: 240-246°C; IR (KBr, cm“1): 3559, 3455, 2940, 2810, 1711, 1657; 1H-NMR (400 MHz, DMSO): δ 2.09 (s, 3H), 2.17 (s, 8H), 2.68 (s, 2H), 3.05 (s, 3H), 3.76 (s, 3H), 5.80 (d, 1H, J = 7.56 Hz), 6.86 (d, 2H, J = 6.72 Hz), 7.11 (d, 1H, J = 6.48 Hz), 7.17 (d, 2H, J = 7.68 Hz), 7.42-7.57 (m, 6H), 10.98 (s, 1H), 12.23 (s, 1H) ; 13C-NMR (100MHz, DMSO): δ 37.17, 46.18, 52.24, 52.79, 55.05, 59.68, 98.10, 109.94, 117.75, 121.96, 124.29, 124.52, 128.06, 128.90, 129.40, 129.92, 130.91, 132.50, 136.72, 140.66, 158.81, 166.84, 169.04 and 170.66; MS: m/z 540 [M]+1.

Step-5: Preparation of (Z)-methyl-3-(((4-(N-methyl-2-(4-methylpiperazin-lyl)acetamide) phenyl) amino)(phenyl)methylene)-2-oxoindoline-6-carboxylate ethane sulfonate salt:

Suspension of (Z)-methyl-3-(((4-(N-methyl-2-(4-methylpiperazin-l-yl)acetamide)phenyl) amino)(phenyl)methylene)-2-oxoindoline-6-carboxylate (36 gm, 0.066 mol) in methanol (237 ml) and water (2.88 ml)was heated to 60-65°C and aq. ethane sulfonic acid was added to the reaction mixture. The resulting solution was cooled to 50°C, seeds diluted with isopropanol (237 ml) was added. The reaction mixture was cooled at 0°C for lhr. Filtered the precipitate, washed with mixture of methanol and isopropanol (50 ml), dried to obtain crude Nintedanib monoethane sulfonate (36.6 gm) and crystallized from methanol (5 Vol) to

obtained pure Nintedanib monoethane sulfonate salt as yellow crystals (33 gm) (80%) (HPLC purity >99%).

DSC: 298°C; IR (KBr, cm-1): 3321, 3273, 1710, 1652, 1615, 1515, 1435, 1378, 1289, 1209, 1161, 1087; 1H-NMR (400 MHz, DMSO): δ 1.08 (t, 3H, J = 7.31 Hz), 2.41-2.47 (q, 2H), 2.50-3.16 (broad m, 13H), 3.37 (s, 3H), 3.76 (s, 3H), 5.82 (d, 1H, J = 7.88Hz), 6.87 (d, 2H, J = 7.36 Hz), 7.14-7.20 (m, 3H), 7.49 (s, 1H), 7.49 (d, 2H, J = 6.68 Hz), 7.56-7.63 (m, 3H), 9.45 (s, 1H), 10.99 (s, 1H), 12.25 (s, 1H), 13C-NMR (100 MHz, DMSO): δ 37.15, 42.79, 45.65, 49.40, 52.26, 53.10, 58.04, 98.25, 110.01, 117.78, 121.97, 124.32, 124.59, 128.27, 128.90, 129.36, 130.00, 131.00, 132.52, 136.79, 137.93, 140.00, 158.66, 166.85, 168.47 and 170.65; MS: m/z 540[M]+1.

Example 2: Process for the preparation of Polymorph Form S of Nintedanib monoethanesulf onate :

Crude Nintedanib monoethane sulfonate was dissolved in methanol and heated to 60-64°C for about 15 min. After completion of the reaction cooled to room temperature for about lhr. Filtered the precipitate, washed with mixture of methanol (20ml) and isopropanol (30 ml) and dried to obtain pure crystalline solid (28 gm) (yield: 93.3%) with HPLC purity 99.72% and individual impurities 0.09%, 0.02% and 0.04%.

SUVEN, Chief executive and chairman Venkat Jasti

//////////WO2016178064,  POLYMORPH,  NINTEDANIB ETHANESULPHONATE, PROCESSES,  INTERMEDIATES, suven, new patent

LUPIN LIMITED, WO 2016181313, NEW PATENT, SOFOSBUVIR


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WO2016181313,  A PROCESS FOR THE PREPARATION OF SOFOSBUVIR INTERMEDIATES & ITS POLYMORPH

LUPIN LIMITED [IN/IN]; Kalpataru Inspire 3rd Floor, Off Western Express Highway Santacruz (East) Mumbai 400 055 (IN)

SINGH, Girij, Pal; (IN).
SRIVASTAVA, Dhananjai; (IN).
MEHARE, Kishor, Gulabrao; (IN).
MALIK, Vineet; (IN).
DEOKAR, Sharad, Chandrabhan; (IN).
DANGE, Abhijeet, Avinash; (IN)

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SUCCESS QUOTIENT: Lupin chairman DB Gupta (sitting) with managing director Kamal K Sharma (centre), directors Vinita Gupta (right) and Nilesh Gupta.

The present invention provides a novel process for preparation N-[(2,3,4,5,6- Pentafluorophenoxy)phenoxyphosphinyl]-L-alanine 1-methylethyl ester (formula 2) and resolving the formula 2 in the presence base to form N-[(S)-(2,3,4,5,6- Pentafluorophenoxy)phenoxyphosphinyl]-L-alanine 1-methylethyl ester (formula 2′).

Sofosbuvir is chemically named as (S)-isopropyl 2-((S)-(((2R,3R,4R,5R)-5-(2,4- dioxo3,4-dihydropyrimidin-l(2H)-yl)-4-fluoro-3-hydroxy-4-methyltetrahydrofuran- 2yl)methoxy)-(phenoxy)phosphorylamino)propanoate and is represented by the following chemical structure:

Formula 1

PCT publications WO2011123645 and WO2010135569 describes process for preparation of compound of formula 2′ by reacting isopropyl (chloro(phenoxy)phosphoryl)-L-alaninate and pentaflurophenol in the presence of base.

Formula 2′

Example-1:

Preparation of sodium 2,3,4,5,6-pentaflurophenolate using sodium hydride

10.2g of sodium hydride was dissolved in 100 ml anhydrous THF. This solution was slowly added to a solution of pentafluorophenol (50g) in THF (100ml), Reaction mass was stirred for 60-120 min at 25-30°C. Reaction mass was distilled under reduced pressure, obtained solid was dried under vacuum at 45-50°C (yield=55g, confirmed by IR)

Example-2:

Preparation of sodium 2,3,4,5,6-pentaflurophenolate using sodium methoxide

2,3,4,5, 6-pentafluorophenol (lOg) was dissolved in methanol (100ml), solution was cooled to 5-10°C. To this was added a solution of sodium methoxide in methanol. The reaction mass was stirred for 60-120 min at 25-30°C. Reaction mass was distilled under reduced pressure, obtained residue was striped with toluene. Obtained solid was dried under vacuum at 45-50°C (yield=l lg)

Example 3:

Preparation of sodium 2,3,4,5,6-pentaflurophenolate using sodium hydroxide

2,3,4,5, 6-pentafluorophenol (lOOg) dissolved in methanol (—ml), solution was cooled to 5-10°C. To this was added a solution of sodium hydroxide (— g) in methanol. The reaction mass was stirred for 60-120 min at 25-30°C. Reaction mass was distilled under reduced pressure, obtained residue was striped with dichloromethane. Obtained solid was dried under vacuum at 45-50°C (yield=— g)

Example 4:

Preparation of (2S)-isopropyl-2-((chloro(phenoxy)posphoryl)amino)propanoate:

phenyl phosphodichloridate (30.6g) was dissolved in dichloromethane , to this was added a solution of 1-alanine isopropyl ester free base (19.16g) in dichloromethane at-60°C under nitrogen. Solution of triethylamine (20.7ml) was added to above reaction mass. Reaction mass was stirredat -60°C for 30 min and then temperature was raised to 25 °C. Reaction mass was stirred at 20-25 °C for 60 min & filtered and washed with dichloromethane. Clear filtrate was distilled under reduced pressure obtained residue was stirred with diisopropyl ether & filtered. Clear filtrate was distilled under reduced pressure to get (2S)-isopropyl-2-((chloro(phenoxy)posphoryl)amino)propanoate compound.

Example 5:

Preparation of isopropyl ((perfluorophenoxy)(phenoxy)phosphoryl)-L-alaninate (formula 2):

(Formula 2)

Obtained (2S)-isopropyl-2-((chloro(phenoxy)phosphoryl)amino)propanoate (1.2 mol eq.) was dissolved in dichloromethane and cooled to 0-5°C under nitrogen atmosphere. To this was added solution of sodium 2,3,4,5,6-pentaflurophemolate (1 mol eq.) in tetrahydrofuran . Temperature of reaction mass was raised to 25°C and reaction mass was stirred for 3 hrs. After completion of reaction, reaction mass was distilled under reduced pressure & obtained residue was dissolved I ethyl acetate. Ethyl acetate layer was washed with water, dried over sodium sulfate & distilled off under reduced pressure. Diisopropyl ether was added to obtained residue and stirred for 60 min at 25 °C, obtained mass was filtered & washed with diisopropyl ether. Solid product was dried under vacuum at 40-45 °C .(yield=20g, enantiomer purity=93.45%)

Example 6:

Preparation of (S)-isopropyl 2-(((S)- (perfluorophenoxy)phenoxy)phosphoyl)amino)propanoate (Formula 2′):

Formula 2′

(2S)-isopropyl-2-((chloro(phenoxy)phosphoryl)amino)propanoate (1.2 mol eq.) was dissolved in tetrahydrofuran (3.5 volumes). The reaction mass was cooled to -10°C. Solution of sodium salt of pentafluorophenol (1 mol eq.) in tetrahydrofuran (3.5 volumes) was added dropwise to the reaction mass at -10°C. After completion of the reaction solvent was distilled off. Ethyl acetate and water were added to the reaction mass. Reaction mass was stirred, ethyl acetate layer was separated and washed with sodium bicarbonate solution and brine. Ethyl acetate layer was concentrated under reduced pressure. Reaction mass was stripped with n-hepatane to get crude product. Crude product was dissolved in Methyl tert-butyl ether and n-heptane (1 : 1 ratio). The pH of reaction mass was adjusted to pH 8 by using triethylamine. Reaction mass was stirred overnight. Solid mass was filtered and washed with a mixture of methyl tertiary-butyl ether: n-heptane (1 : 1). The obtained product was dissolved in ethyl-acetate and washed with water and 20% brine solution. Ethyl acetate layer was separated; solvent was distilled off under reduced pressure. Reaction mass was stripped with diisopropyl ether. Di-isopropyl ether was added to the reaction mass. Reaction mass was stirred at 45-50°C. Reaction mass was cooled to 5-10°C and stirred. The titled compound was isolated by filtration and washed with di-isopropyl ether. The titled compound was dried under reduced pressure at 40°C. Yield 66.81%.

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Vinita Gupta, CEO, Lupin Pharmaceuticals Inc

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Desh Bhandu Gupta- Founder and chairman of Lupin Limited

////////////LUPIN LIMITED, WO 2016181313,  NEW PATENT, SOFOSBUVIR

WO 2016147197, DAPAGLIFLOZIN, NEW PATENT, HARMAN FINOCHEM LIMITED


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Dapagliflozin structure.svg

WO 2016147197, DAPAGLIFLOZIN, NEW PATENT, HARMAN FINOCHEM LIMITED

LINK>>> (WO2016147197) A NOVEL PROCESS FOR PREPARING (2S,3R,4R,5S,6R)-2-[4-CHLORO-3-(4-ETHOXYBENZYL)PHENY 1] -6-(HY DROXY METHYL)TETRAHYDRO-2H-PY RAN-3,4,5-TRIOL AND ITS AMORPHOUS FORM

HARMAN FINOCHEM LIMITED [IN/IN]; 107, Vinay Bhavya Complex 159-A, C.S.T. Road Kalina, Mumbai 400098 Maharashtra (IN)

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KADAM, Vijay Trimbak; (IN).
SAIKRISHNA; (IN).
CHOUDHARE, Tukaram Sarjerao; (IN).
MINHAS, Harpreet Singh; (IN).
MINHAS, Gurpreet Singh; (IN)

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CHAIRMAN

HARPREET SINGH MINHAS

HARPREET SINGH MINHAS

Owner, HARMAN FINOCHEM LIMITED

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(2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol is sodium dependent glucose transporter (SGLT) which is currently under investigation for the treatment of type-2 diabetes. (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol is marketed under the tradename Farxiga or Forxiga.

(2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol is also known as D-glucitol, l,5-anhydro-l-C-[4-chloro-3-[(4ethoxyphenyl)methyl]phenyl]-, (I S). (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3, 4,5 -triol is a white to off-white powder with a molecular formula of C2iH25C106 and a molecular weight of 408.87

Formula-I

US 6,515,117 B2 discloses (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol and its pharmaceutically acceptable salts. US 6,515,117 B2 also describes process for preparation of (2S,3R,4R,5S,6R)-2-[4- chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol which comprises reaction of 5-bromo-2-chloro-4′-ethoxydiphenylmethane with 2,3,4,6-tetra-O-trimethylsilyl- -D-glucolactone in presence of THF/Toluene, methansulfonic acid to yield o-methylglucoside product which further reacts with Et3SiH, BF3Et20 in presence of MDC and acetonitrile to yield yellow solidified foam which is dissolved in MDC, pyridine and followed by acetylation with acetic anhydride, DMAP to yield tetra acetylated- β-C-glucoside as a white solid which is further deprotected with LiOH H20 in presence of THF/MeOH/H20 to get (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol.

The drawback of said prior art is having multiple process steps which makes the process very lengthy and tedious. Moreover the process discloses use of hazardous chemicals like pyridine which is not applicable to industry.

Process for preparation of (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenylJ-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol is disclosed in US 7,375,213 B2 and J.Med.Chem.2008, 51, 1145-1149. The preparation process is depicted in Scheme-I.

Scheme-1

Prior art US’213 describes reaction of 2-chloro-5-bromo-4′-ethoxy-diphenylmethane with 2,3,4,6-tetra-O-trimethylsilyl-D-gluconolactone, n-BuLi in presence of THF and Heptane. After basification with TEA, the oily residue of methyl- l-C-(2-chloro-4′- ethoxy-diphenylmethan-3-yl)-a-D-glucopyranose obtained as solid compound after workup. This compound reacts with acetic anhydride in presence of THF, DIPEA and DMAP to get oily residue of methyl-2,3,4,6 tetra-0-acetyl-l-C-(2-chloro-4′-ethoxydiphenylmethan-3-yl)-a-D-glucopyranose which further undergoes reduction reaction in presence of acetonitirle, t riethylsilane, boron trifluoride etherate to yield 2,3,4,6-tetra-0-acetyl-l-C-(2-chloro-4′-ethoxydi henylmethan-3-yl)-β-D-glucopyranose which is further deprotected by reacting with LiOH monohydrate in presence of THF/MeOH/H20 to get (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol.

The said prior art describes multiple, time consuming process steps which involves getting the intermediate products as oily residue at various stages of the process, which is difficult to purify and handle for further process step. More over the workup involves multiple evaporation of product which may result in decomposition. Another drawback of the process is that the process describes n-BuLi reaction with two pot reaction. It is very difficult to transfer the material from one reactor to second reactor at -78 °C at industrial level with highly moisture sensitive reaction mass. This makes process uneconomical, cumbersome and commercially not viable. Further when practically the said method followed, a-Isomer of the final product is formed in the range of 6-8% along ith Des-bromo impurity formed in the range of 7-9 %, which increases after addition of n-butyllithium and kept the mass for overnight reaction. Moreover lactone ring cleavage is also observed in the range of 3-4% after addition of Methanesulphonic Acid/Methanol and maintained overnight for reaction completion, the removal of which is difficult from the final product.

WO 2008002824 A 1 discloses crystalline forms of (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol comprising (S)-propylene glycol (PG), (R)-PG, EtOH, ethylene glycol (EG), 1 :2 L-proline, 1 : 1 L-proline, 1 : 1 L-proline hemihydrate, 1 : 1 L-phenylalanine and its preparation process.

In the light of the above drawbacks, it is necessitated to provide economical, robust, safe and commercially viable process for preparing (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol.

Accordingly, it is an objective of the present invention to provide a commercially viable process for the preparation of (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxyb.enzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol, prepared via riovel intermediates which gives higher yield and purity and facilitates easy recovery of the final compound. The purification process does not involve any costly technique/equipment, however, carried out with solvents which are industrially feasible. More over the present invention discloses the n-BuLi insitu reaction that makes the present invention cost-effective over the teachings of prior art.

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Scheme-II

Formula-Ill Formula-IV

Formula-V where R1= allyl, prop-2-ynyl,isopropyl

Scheme-Ill

where R = allyl, prop-2-ynyl

Scheme-IV

Scheme-V

Examples:

Example-1: Preparation of 3,4,5-Tris-trimethylsiIanyloxy-6-trimethylsiIanyloxymethyl-tetrahydro-pyran-2-one

To 750 cc of dry THF added 1.12 mole 3,4,5-Trihydroxy-6-hydroxymethyl-tetrahydro-pyran-2-one at ambient temperature and stirred for 20 min. To the reaction mass added 9.0 mole N-Methyl morpholine and stirred for another 30.0 min at ambient temperature. Reaction mass was cooled to -5 °C to 0 °C and stirred for 30.0 min. Added 18.0 mole Trimethyl sillyl chloride at the temp -5 °C to 0 °C and stirred for 30.0 min. Temperature was raised to 25 °C to 30 °C and maintained for 18-20hrs. After reaction complies by GC, the reaction mass was cooled to -5 deg to 0 deg. Added Sat.Sodium bicarbonate solution to obtain the pH 7-8 and stirred for 1 hr at 0 °C. Added 500 cc toluene and stirred for lhr. Reaction mass was settled down for 30.0 min and layers were separated. To the Aqueous layer added 250 cc of toluene and stirred for 30.0 min. Layers separated and both the organic layers mixed and back washed with sat.brine solution. Organic layer was distilled under reduced pressure at a temperature of about 40 – 48 deg. Unload the oily mass . Purity: 92-96 %

Example-2: Preparation of 2-Allyloxy-2-[4-chloro-3-(4-ethoxy-benzyl)-phenyl]-6-hydroxymethyI-tetrahydro-pyran-3,4,5-triol

To the mixture of 10 cc THF and 10 cc Toluene added 0.138 mole 4-(5-bromo-2-chlorobenzyl)phenyl ethyl ether at ambient temperature and stirred for 15 min. Cooled to -70 to -80°C in dry ice /acetone bath and stirred for 15 min. Added a solution of 0.014 mole n-Butyl lithium (1.9M in hexanes) at -70 to -80°C. and stirred for lhr. Added solution of 3, 4, 5-Tris-trimethylsilanyloxy-6-trimethylsilanyloxymethyl-tetrahydro-pyran-2-one in 5 cc of Toluene at -70 to -80°C and stirred for 2 to 3hrs. After the compliance of the reaction, reaction mass was quenched with Methane sulphonic acid and Allyl alcohol mixture at -70 to -80°C. Temperature was raised to ambient temperature and stirred overnight. Reaction mass was quenched with 30 cc sat.sodiumbicarbonate solution to bring the pH neutral to alkaline and stirred for 30.0 min. Layers separated and aqueous layer was extracted with 10 cc of Toluene. Organic layer was combined and washed with 30cc water and 50 cc sat. brine solution. Organic layer was distilled under reduced pressure to recover toluene. Solid compound was dissolved in 50cc of toluene and quenched in n-Hexane to obtain 83 % the compound as crystalline solid.

HPLC purity: 88 – 91 %

I R data:

Anomeric C-0 stretching: 1242 cm“1

Allylic C- O stretching: 1 177 cm“1

Allylic C- H stretching: 3010 – 3120 cm“1

Aromatic C- CI stretching: 820 cm“1

Lactones O – H stretching: 3240 – 3380 cm“1

Lactones C – 0 stretching: 1045 – 1092 cm“1

Aromatic C=C stretching: 1510 , 1548 , 1603 , 1703 cm“1

Alkane C – H stretching: 2877,2866, 2956, 2958, 2962 cm“1

Aromatic C – H stretching: 3050 – 3090 cm“1

Dip-Mass

(M+Na) 487.19 m/z

(M+K) 503.17 m/z

Example 3: Preparation of 2-prop-2ynyl-2-[4-Chloro-3-(4-ethoxy-benzyl)-phenyl]-6-hydroxymethyl-tetrahydro-pyran-3,4,5-triol

To the mixture of 10 cc THF and 10 cc Toluene added 0.138 mole 4-(5-bromo-2-chlorobenzyl)phenyl ethyl ether at ambient temperature and stirred for 15 min. Cooled to -70 to -80°C in dry ice /acetone bath and stirred for 15 min. Added a solution of 0.014 mole n-Butyl lithium (1.9M in hexanes) at -70 to -80°C. and stirred for lhr. Added solution of 3, 4, 5-Tris-trimethylsilanyloxy-6-trimethylsilanyloxymethyl-tetrahydro-pyran-2-one in 5 cc of Toluene at -70 to -80°C and stirred for 2 to 3hrs. After the compliance of the reaction, the reaction mass was quenched with Methane sulphonic acid and propargyl alcohol mixture at -70 to -80°C. Temperature was raised to ambient temperature and stirred overnight. Reaction mass was quenched with 30 cc sat.sodiumbicarbonate solution to bring the pH neutral to alkaline. Reaction mass stirred for 30.0 min. Layers separated and aqueous layer was extracted with 10 cc of Toluene. Organic layer were combined and washed with 30cc water and 50 cc sat. brine solution. Organic layer was distilled under reduced pressure to recover toluene. Solid compound dissolved in 50cc of toluene and quenched in n-Hexane to obtain 75 – 80 % the compound as crystalline solid.

HPLC purity: 88 – 93 %

IR data:

Anomeric C-0 stretching: 1242 cm“1

Propargyl ~c CH stretching: 2125 cm“1

Propargyl C- H stretching : 3010 – 3120 cm“1

Aromatic C- CI stretching: 820 cm“1

Lactones O – H stretching: 3240 – 3380 cm“1

Lactones C – 0 stretching: 1045 – 1092 cm“1

Aromatic C=C stretching: 1510 , 1548 , 1603 , 1703 cm“1

Alkane C – H stretching: 2877, 2866,2956,2958,2962 cm“1

Aromatic C – H stretching: 3050 – 3090 cm“1

Dip-Mass

(M+Na) 485.25 m/z

(M+K) 501.25 m/z

Example-4: Preparation of 2-[4-Chloro-3-(4-ethoxy-benzyl)-phenyl]-6-hydroxymethyI-tetrahydro-pyran-3,4,5-trioI

To the mixture of 20 cc (1 : 1 MDC + ACN) added 0.1 1 mole 2-Allyloxy-2-[4-chloro-3-(4-ethoxy-benzyl)-phenyl]-6-hydroxymethyl-tetrahydro-pyran-3,4,5-triol under argon atmosphere, and stirred the reaction mass for 30.0 min. Cooled the reaction mass to -40 to -55°C in a dry ice/acetone bath under argon atmosphere. Charged 3 mole Triethylsilane at -40 to -55°C and stirred the reaction mass for 30.0 min at -50 to -55°C. Slowly added Borontrifloride in diethyl ether solution at -40 to -55°C and stirred the reaction mass for 2 hrs. Quenched the reaction mass with 50 cc sat. sodium bicarbonate solution at -40 to -55°C . and stirred the reaction mass for 30.0 min. Slowly raised the temperature to 25 to 30°C. Settled down the reaction mass and separated the layers, extracted the aqueous layer with 100 cc of MDC. Combined the organic layer and wash with 500 cc water. Washed the organic layer with 500 cc of sat. Brine solution. Distilled out the MDC under reduced pressure below 40°C. to get 85 %the light yellow solid.

HPLC purity: 92-95 %

Example 5: Preparation of 2-[4-Chloro-3-(4-ethoxy-benzyl)-phenyl]-6-hydroxymethyl-tetrahydro-pyran-3,4,5-triol

To the mixture of 20 cc (1 :1 MDC + ACN) added 0.11 mole 2-prop-2-ynyl-2-[4-Chloro-3-(4-ethoxy-benzyl)-phenyl]-6-hydroxymethyl-tetrahydro-pyran-3,4,5-triol under argon

atmosphere. Stirred the reaction mass for 30.0 min. Cooled the reaction mass to -40 to -55°C in a dry ice/acetone bath under argon atmosphere. Charged 3 mole Triethylsilane at -40 to -55°C and stirred the reaction mass for 30.0 min at -50 to -55°C. Slowly added Borontrifloride in diethyl ether solution at -40 to -55°C and stirred the reaction mass for 2 hrs. Quenched the reaction mass with 50 cc sat. sodium bicarbonate solution at -40 to -55°C and Stirred the reaction mass for 30.0 min. Slowly raised the temperature to 25 to 30°C. Settled down the reaction mass and separated the layers, extracted the aqueous layer with 100 cc of MDC. Combined the organic layer and washed with 500 cc water. Washed the organic layer with 500 cc of sat. Brine solution. Distilled out the MDC under reduced pressure below 40°C. to get 85%the light yellow solid.

HPLC purity: 90%

Example 6: Preparation of amorphous form of (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol

To the solid obtained from example 4 charged 500cc of n-heptane and stirred for ½hrs at ambient temperature. Heated the reaction mass to 55-60°C and stirred it for 2-3 hrs.; cooled to room temperature and maintained for 4-5 hrs. Filtered the solid and washed the, cake with 100 cc n-heptane. Dried at 40-45°C under vacuum to get 85% amorphous form of (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol.

HPLC purity: 91-93%

Example 7: Preparation of amorphous form of (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol

To the solid obtained from example 5 charged 500cc of n-heptane and stirred for ½ hrs at ambient temperature. Heated the reaction mass to 55-60°C and stirred it for 2-3 hrs., cooled to room temperature and maintained for 4-5 hrs. Filtered the solid and washed the cake with 100 cc n-heptane. Dried at 40-45 °C under vacuum to get 85-88% amorphous form of (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6- (hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol.

HPLC purity: 89-91%

Example 8: Preparation of L-proline – (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyI]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol co crystal

To the 10 cc of Ethyl acetate charged 1.0 mole (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol under argon atmosphere at ambient temperature and stirred for 30.0 min to get clear solution. Slowly heated the reaction mass to 60 – 65°C and stirred for 1 hr. Slowly added L-proline at 60 -65°C and maintained for 1 hr. Slowly added 15 cc n-Heptane to the reaction mass at 60 -65°C and stirred the mass for 2.5 hrs. Cooled the mass to ambient temperature for 3-4 hrs and maintained for 5 hrs. Filtered the mass under argon atmosphere. Washed the cake with 10 cc n-Heptane. Dried the cake at 50-55°C under reduced pressure to get 92% titled compound.

HPLC purity: 99%

Example 9: Preparation of L-proline – (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triolco crystal

To the 10 cc of acetone charged 1.0 mole (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol under argon atmosphere at ambient temperature and stirred for 30.0 min to get clear solution. Slowly heated the reaction mass to 60 – 65°C and stirred for 1 hr. Slowly added proline at 60 -65°C and maintained for 1 hr. Slowly added 15 cc n-Heptane to the reaction mass at 60 -65°C and stirred the mass for 2.5 hrs. Cooled the mass to ambient temperature for 3-4 hrs and maintained for 5 hrs. Filtered the mass under argon atmosphere. Washed the cake with 10 cc n-Heptane. Dried the cake at 50-55°C under reduced pressure to get 93-95% titled compound.

HPLC purity: 98-99%

Example 10: Preparation of amorphous form of (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol

To the 15 cc ethyl acetate added (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol at ambient temperature and stirred for 30.0 min. Slowly added 5- 8 cc sat. sodium bicarbonate solution at ambient temperature and stirred for 1.5 hr to get the clear solution. Settled down and separated layers. Extracted the aqueous layer with 25 cc ethyl acetate.

Combined the organic layers and washed the ethyl acetate layer with 50 cc sat. Sodium chloride solution. Distilled out ethyl acetate under reduced pressure at 40 – 45°C to get fluffy solid. Charged 50 cc n-Heptane and stirred for 5 hrs to get 70-78% the title compound as Amorphous soild.

HPLC purity: 99.8-99.95 %

Example 11: Preparation of 2-chloro -4′- ethoxydiphenylmethane (impurity)

To the 20 cc THF and 20 cc Toluene added 0.25 mole 2-ehloro-5-bromo-4′- ethoxydiphenylmethane under argon atmosphere. Cooled the reaction mass to – 78° C. Slowly added n-Butyl lithium (1.9 M in hexane) at – 78° C and stirred for 30 min. Slowly added 20 % Ammonium chloride solution to the reaction mass. Brought the reaction mass to ambient temperature and stirred for 30 min. Settled and separated layers. Extracted the aqueous layer with 50 cc toluene. Washed the combined organic layer with 500 cc brine solution. Distilled out the toluene and charged heptanes, stirred for 2 – 3 hrs at ambient temperature. Filtered the product and dried the product at 45 – 50°C under reduced pressure to get 93 % titled compound.

Mass: (m+1) 247 m/z found 247.1 1

HPLC purity: 96.33 %

SHENDRA AURANGABAD, MAHARASHTRA, INDIA

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Bhupinder Singh Manhas

 

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////////WO 2016147197, DAPAGLIFLOZIN, NEW PATENT, HARMAN FINOCHEM LIMITED

WO 2016147120, AZILSARTAN, NEW PATENT, SMILAX Laboratories Ltd


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Azilsartan.svg

WO-2016147120, AZILSARTAN, NEW PATENT, SMILAX Laboratories Ltd

SMILAX LABORATORIES LIMITED [IN/IN]; Plot No. 12/A, Phase – III, I.D.A. Jeedimetla, Hyderabad 500 055 (IN).

The present invention relates to an improved process for the preparation of substantially pure compound of 2-Ethoxy-1-[[2′-(2,5-dihydro-5-oxo-1,2,4-oxadiazol- 3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylic acid (Azilsartan) of Formula I, with a reduced content of desethyl impurity less than 0.1% and an efficient, commercially viable process for the preparation of pure intermediates of Azilsartan.
KOTAGIRI, Vijaya Kumar; (IN).
YENUMULA, Raghavendra Rao; (IN).
BANDARI, Mohan; (IN).
SURYADEVARA, Murali Krishna; (IN)
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(WO2016147120) AN IMPROVED PROCESS FOR THE PREPARATION OF SUBSTANTIALLY PURE AZILSARTAN

Azilsartan (I) is an angiotensin receptor II antagonist used in the treatment of hypertension. Angiotensin II causes vasoconstriction via an angiotensin II receptor on the cell membrane and elevates blood pressure.

Azilsartan medoxomil i.e. (5-methyl-2-oxo-l,3-dioxol-4-yl)methyl 2-ethoxy-l-[[2′-(2,5-dihydro-5-oxo-l,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylic acid is developed by Takeda pharmaceuticals and is marketed under the trade name Edarbi. It was approved by USFDA on 25 Feb, 2011 and EMEA on 7 Dec 2011 for the treatment of high blood pressure in adults.

Azilsartan medoxomil and its salts thereof are imbibed with properties such as strong and long lasting angiotensin II antagonistic activity and hypotensive action which has an insulin sensitizing activity useful for the treatment of metabolic diseases such as diabetes and the like., and a useful agent for the prophylaxis or treatment of circulatory diseases such as hypertension, cardiac diseases, nephritis and stroke. Azilsartan medoxomil is the prodrug of 2-Ethoxy-l-[[2′-(2,5-dihydro-5-oxo-l,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylic acid (Azilsartan).

Methods of preparing benzimidazole derivative useful as an angiotensin II receptor antagonist such as Azilsartan Medoxomil and salts thereof are disclosed by Takeda in US 5,243,054 (herein after referred as US ‘054 patent). The US’054 patent describes several synthetic routes for preparing Azilsartan. According to one of the synthetic process, the compound of formula II is reacted with hydroxylamine hydrochloride in a conventional organic solvent and sodium methoxide in methanol to give the amidoxime compound of formula III which on further reaction with ethyl chloroformate in presence of triethylamine base in refluxing xylene undergoes cyclization to provide a compound of formula IV. Azilsartan was prepared by hydrolysis of compound of formula IV in presence of lithium hydroxide by adjusting the pH with HC1. The process is as depicted below in Scheme A:

However, the amidoxime compound of formula III obtained by the above process contains about 50% of amide imputiy along with desired product, owing to the strong reaction conditions which impairs the quality and loss of yield. The pH adjustment with HC1 in the hydrolysis step of compound IV results in the formation of an undesired desethyl impurity of formula V due to acid sensitive nature of the ether linkage in the benzimidazole moiety of Azilsartan.

Formula V

According to another method disclosed in US’054 for the preparation of Azilsartan comprises by reacting ethoxycarboimidoyl biphenyl benzimidazole derivative of compound with ethyl chloroformate to give N-methoxycarbonyl ethoxycarboimidoyl biphenyl benzimidazole derivative, which is further converted to compound of formula IV and then to Azilsartan of formula I by hydrolysis.

According to one another embodiment method for the preparation of Azilsartan disclosed in US ‘054, cyanobiphenyl aminobenzoate derivative compound reacts with hydroxylamine hydrochloride in presence of triethylamine subsequently followed by addition of ethyl chlorocarbonate results in the formation of compound of formula IV which is further hydrolyzed to obtain Azilsartan of formula I.

J. Med. Chem. Vol. 39, No. 26, 5230-5237 (1996) describes the use of triethylamine as base during the conversion of compound of formula II to amidoxime compound of formula III and use of 2-ethylhexylchloroformate instead of ethylchloroformate as cyclizing agent.

Processes for the preparation of Azilsartan medoxomil and its potassium salt are described in US 7,157,584 which comprises reacting Azilsartan with 4-hydroxymethyl-5-methyl-l,3-dioxol-2-one in presence of dimethylacetamide, p-toluoyl sulfonylchloride, 4-dimethylaminopyridine and potassium carbonate.

PCT publication WO 2012/107814 discloses process for the preparation of Azilsartan or its esters or salts by reacting amidoxime compound of formula III with carbonyl source such as carbodiimides, dialkyl carbonate and phosgene equivalents in presence of a suitable base to obtain compound of formula IV which is further converted to Azilsartan and its pharmaceutically acceptable salts. The process for the preparation of Azilsartan is as depicted in Scheme B:

Scheme – B

This publication also discloses that use of a carbonyl source reduces the formation of the content of desethyl impurity during cyclization.

Polymorphs of Azilsartan and its salts are disclosed in WO 2013/044816 and WO 2013/186792.

All the above prior art methods for the preparation of Azilsartan have inherent disadvantages such as the usage of unsafe reagents, high boiling solvents, extreme reaction conditions invariably resulting in the formation of low pure intermediates as well as Azilsartan having a considerably higher content of desethyl impurity. Accordingly, there remains a need for the industrial preparation of substantially pure Azilsartan which is free of impurities with high yield.

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Examples

Example-1: Preparation of Methyl-2-ethoxy-l-[[2′- ((hydroxycarbamimidoyl)biphenyl)-4-yl]methyl]-lH-benzimidazole-7-carboxylate (Formula-Ill):

To a stirred solution of DMSO (1500.0 mL), Hydroxylamine hydrochloride ( 126.7g 1.83mol) and Dipotassium hydrogen phosphate (634.9g 3.65mol) was added Methyl l-[[2′-cyanobiphenyl-4-yl]methyl]-2-ethoxybenzimidazole-7-carboxylate (lOO.Og 0.243mol) at 25-30°C. The reaction mass temperature was raised to 80-85°C and maintained for 30-40 hours. Reaction completion was monitored by TLC. Upon completion of reaction, reaction mass was cooled to 10- 15°C, and was poured into water (3000.0 mL), stirred for 45min at 20-25°C. and was filtered. The filtered wet solid was washed with water and dried at 65°C to get crude Methyl-2-ethoxy-l-[[(2′-(hydroxycarbarmrmdoyl)biphenyl-4-yl]methyl]-lH-benzimidazole-7-carboxylate. The wet material was slurried in Acetone (optional) at reflux and filtered at room temperature to obtain pure compound.

Yield: 79.92 g, 74.0%; HPLC Purity: 97.78%; Desethyl impurity: 0.318%; Amide impurity: 1.42%.

Example-2: Preparation of Methyl 2-ethoxy-l-[[2′-(2,5-dihydro-5-oxo-l,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylate (Formula-IV) :

To the pre cooled solution of Methylene dichloride (375.0 mL) and Methyl-2-ethoxy-1 -[[2′ -((hydroxycarbamimidoyl)biphenyl)-4-yl] methyl]- lH-benzimidazole-7-carboxylate (75.0g, 0.168mol) was added ethyl chloroformate ( 18.3g 0.168mol)

followed by addition of triethylamine (18.75g 0.185mol). The reaction mass was maintained at 0-5 °C for about 1 hour. Upon completion of the reaction, reaction mass was poured into water (200.0 mL), organic layer was separated and washed with 5% NaHC03 solution (150.0 mL) and then with water (150.0 mL). The organic layer was dried over sodium sulfate and distilled to obtain the crude material (optionally be isolated using cyclohexane solvent). To this obtained crude material, ethyl acetate (750.0mL) and potassium carbonate (112.5g 0.814mol) were added and heated to reflux for 6 to 8 hours. The contents were cooled, filtered and wet solid was slurried in water. Wet material so obtained was slurried in ethyl acetate at reflux and filtered at room temperature and dried at 60-65°C to give Methyl 2-ethoxy-l-[[2′-(2,5-dihydro-5-oxo-l,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylate.

Yield: 64.27 g, 81.0 %; HPLC Purity: 99.80%; Desethyl impurity: 0.085%.

Example-3: Preparation of 2-Ethoxy-l-[[2′-(2,5-dihydro-5-oxo-l,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylic acid (Azilsartan)

A mixture of 0.4N NaOH solution (395.8 mL) and Methyl 2-ethoxy-l-[[2′-(2,5-dihydro-5-oxo-l,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylate (25. Og) were stirred at 50-55°C for period of 60min. The reaction mass was cooled to room temperature and the product layer was washed with ethyl acetate (125.0mL). pH of the separated aqueous product layer was adjusted to 4.0 to 5.0 using dilute acetic acid at 0-5 °C. The obtained solid material was filtered and washed with water (lOO.OmL). This material was dried to obtain the title product.

Yield: 20.0 g, 82.47%; HPLC Purity : 99.80%; Desethyl impurity: 0.10%.

Example-4: Preparation of 2-Ethoxy-l-[[2′-(2,5-dihydro-5-oxo-l,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylic acid (Azilsartan)

A mixture of 0.4N NaOH solution (633.33 mL) and Methyl 2-ethoxy-l-[[2′-(2,5-dihydro-5-oxo-l,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylate (40.0g) were stirred at 50-55°C for period of 60min. The reaction mass was cooled to room temperature and the product layer was washed with ethyl acetate (200.0mL). pH of the separated aqueous product layer was adjusted to 4.0 to 4.5 using acetic acid at 10-15°C. The obtained solid material was filtered and washed with water (lOO.OmL). This material was dried to obtain the title product.

Yield: 32.35 g, 83.37%; HPLC Purity: 99.45%; Desethyl impurity: 0.12%.

Example-5: Preparation of 2-Ethoxy-l-[[2′-(2,5-dihydro-5-oxo-l,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylic acid (Azilsartan)

A mixture of 0.4N NaOH solution (791.66 mL) and Methyl 2-ethoxy-l-[[2′-(2,5-dihydro-5-oxo-l,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylate (50.0g) were stirred at 50-55°C for period of 60min. The reaction mass was cooled to room temperature and the product layer was washed with ethyl acetate (250.0mL). pH of the separated aqueous product layer was adjusted to 3.0 to 4.0 using citric acid at 10-15°C. The obtained solid material was filtered and washed with water (125.0mL). This material was dried to obtain the title product.

Yield: 37.0 g, 76.28%; HPLC Purity: 99.69%; Desethyl impurity: 0.083%.

Example-6: Preparation of 2-Ethoxy-l-[[2′-(2,5-dihydro-5-oxo-l,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylic acid (Azilsartan)

A mixture of 0.4N NaOH solution (395.83 mL) and Methyl 2-ethoxy-l-[[2′-(2,5-dihydro-5-oxo-l,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylate (25. Og) were stirred at 50-55°C for period of 60min. The reaction mass was cooled to room temperature and the product layer was washed with ethyl acetate (lOO.OmL). pH of the separated aqueous product layer was adjusted to 3.0 to 4.0

using hydrochloric acid at 10-15°C. The obtained solid material was filtered and washed with water (72.5 mL). This material was dried to obtain the title product. Yield: 20.22 g, 83.37%; HPLC Purity: 99.45%; Desethyl impurity: 0.217%.

Example-7: Purification of 2-Ethoxy-l-[[2′-(2,5-dihydro-5-oxo-l,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylic acid (Azilsartan)

Charged 2-Ethoxy- 1 – [[2′ -(2,5-dihydro-5-oxo- 1 ,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylic acid (lOO.Og), methanol (600.0ml) and methylene dichloride (600.0ml) and were stirred for 10 min at 25-30°C to get a clear solution. Above solution was treated with Activated carbon (lO.Og) and stirred for 10.0 min at 25-30°C. Reaction mixture was passed through a hyflow bed and washed with a mixture of (1: 1) ratio of 200.0ml methanol and methylene dichloride. The solvent mixture was distilled out at below 50°C till the solid formation was observed. Reaction mixture is stirred for 30.0min at 30°C, then the solid was filtered and washed with 200.0ml of methylene dichloride. To the obtained solid, methanol (450.0 ml) was charged at 25-30°C, heated to 45°C, stirred for 30 min at 45°C and then cooled to 30°C. After cooling, the solid was filtered and washed with methanol (90.0ml) which was further dried at 50-55°C for 12 hours.

Yield: 80.0 g, 80.0%; HPLC Purity: 99.96%; Desethyl impurity : 0.012%.

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Accreditation

Smilax Managing Director, S. Murali Krishna received the award from Hon’ble Chief Minister of Andhra Pradesh Shri. N. Kiran Kumar Reddy.

WO 2016113415, Sandoz, Riociguat, New Patent


WO 2016113415, Sandoz, Riociguat, New Patent

STEFINOVIC, Marijan; (AT).
RICHTER, Frank; (AT).
GRIESSER, Ulrich; (AT).
LANGES, Christoph; (AT)

SANDOZ AG [CH/CH]; Lichtstrasse 35 4056 Basel (CH)

WO 2016113415

Novel method for purifying riociguat, useful for treating chronic thromboembolic pulmonary hypertension, pulmonary arterial hypertension, systemic sclerosis and Raynaud’s phenomenon. Also claims novel crystalline solvates of riociguat (eg ethyl acetate or butan-2-one solvate), useful as intermediates in the purification of riociguat. Bayer and licensee Merck have developed and launched riociguat.

The present filing appears to be the first filing from Sandoz on riociguat; however see WO2015095515, assigned to Novartis, parent company of Sandoz, claiming an ophthalmic composition comprising a soluble guanylate cyclase activator (eg riociguat).

Riociguat (BAY 63-2521 ), having the chemical name N-[4,6-Diamino-2-[1-(2-fluorobenzyl)-1 H-pyrazolo[3,4-b]pyridin-3-yl]pyrimidin-5-yl]-N-methylcarbamic acid methyl ester, or sometimes also called or also sometimes called Methyl-(4,6-diamino-2-(1-(2-fluorobenzyl)-1 H-pyrazolo[3, 4-b]pyridin-3-yl)-5-pyrimidinyl)(methyl)carbamate is a stimulator of the soluble guanylate cyclase.

Riociguat has been approved for the treatment of inoperable, or persistent, recurrent chronic thromboembolic pulmonary hypertension (CTEPH) after surgery in adult patients and for the treatment of pulmonary arterial hypertension and is in development for the treatment of systemic sclerosis and Raynaud’s phenomenon.

(I)

The preparation of the compound of formula (I) and its purification are known. According to the experimental procedure of Example 8 of WO 03/095451 (comparable description in Chem. Med. Chem 2009, 4, 853-865), iodomethane is used as an alkylating agent in a late step and the purification of the crude riociguat either comprised preparatory HPLC steps or several steps of extracting, precipitating, suspending, washing, redissolving and reprecipitating riociguat, resulting in a long and tedious workup procedure with moderate yield.

In WO 201 1/064171 a potential genotoxic azo compound of formula III is used as a key intermediate, which under catalytic hydrogenation forms a compound of formula VIII.

The compound of formula VIII is further reacted with a methyl chloroformate or with a dimethyl carbonate derivative to form a compound of formula VI. The compound of formula VI is then methylated to form crude riociguat of formula (I).

Crude riociguat of formula (I) is then purified by a process comprising the intermediate isolation of a riociguat DMSO solvate of formula (II).

For the pharmaceutical use of riociguat, the solvent DMSO has to be removed. To that end, the compound of formula (II) is boiled in pharmaceutically acceptable solvents such as ketones, esters, ethers or alcohols. However, the riociguat obtained in this manner contains detectable amounts of DMSO.

These processes for the preparation of riociguat and their laborious purification protocols have a number of disadvantages which are unfavorable for industrial realization on a large scale.

On the one hand, the purification process according to WO 03/095451 require the repeated isolation of solid intermediates or preparatory HPLC, which ultimately results in a reduced yield of pure riociguat of formula (I) of pharmaceutical grade. Yet, traces of compound of formula (III) remain.

It is therefore one of the objects of the present invention to provide a process for the preparation of pure riociguat – compound of the formula (I) – which yields riociguat free from any genotoxic impurity and/or mutagenic impurity.

On the other hand, the process for the preparation of riociguat described in WO 201 1/064171 has a different serious drawback. It comprises the use of a DMSO solvate.

DMSO is an active pharmaceutical ingredient by itself. It is used as an active pharmaceutical ingredient in the treatment of interstitial cystitis. DMSO removal is difficult to achieve by the published processes. It is thus a further object of the invention to provide riociguat essentially free from DMSO and suitable for pharmaceutical use.

WO 2014/128109 discloses forms of riociguat, such as polymorphs and solvates, and describes a ¼ ethyl acetate solvate of riociguat in example 6. The X-ray powder

diffractogram in Tab.3 and figure 4 comprises reflexes at °2Theta positions of 9.1 and 25.6.

Thus, there is a need in the art for a process, which allows the preparation of pure riociguat free from any genotoxic impurity and/or mutagenic impurity which at the same time does not comprise residual DMSO.

Surprisingly, we have now identified a process for the purification of crude riociguat which yields riociguat which is essentially free from genotoxic impurities and DMSO. In particular, this novel process differs from the processes known to date in that the isolation of intermediates prior to the formation of riociguat is not required. This process allows to overcome the disadvantages of the processes known to date and to obtain riociguat in high yield and high purity and pharmaceutical acceptable quality essentially free of genotoxic impurities.

 

Examples

Preparative example

Preparation of crude riociguat

Riociguat was prepared as disclosed in example 7 of WO 201 1/064171 and had a chemical purity of 91.7% by the area of the riociguat peak in the HPLC-UV elution profile.

Comparative Example 1

Preparation of DMSO solvate

An amount of 4.505 g (0.0107 moles) of crude riociguat was dissolved in 8 ml DMSO at 100 °C. The obtained brownish, turbid solution was then cooled to 75 °C within 16 minutes. After that 55 ml of ethylacetate were added and the mixture was cooled to 25 °C (30 minutes). After 22 h the obtained precipiate was filtered off, washed with 14 ml EtOAc and dried for 4 hours at 50 °C at reduced pressure (50 mbar). The precipitate was analysed with XRPD, confirming that riociguat DMSO was obtained. The product was also analyzed by HPLC-UV-MS. Purity was calculated based on UV detection at 254nm. The so obtained riociguat DMSO solvate was 91 .92% pure.

Comparative Example 2

Preparation of riociguat form I from riociguat DMSO solvate

The entire product prepared in comparative example 1 (4.283 g = 0.009 moles) was reflux heated in 77 ml of ethylacetate at 78 °C for 1 h and then cooled to 25 °C. The white solid was filtered off with suction, washed with a total of 18 ml of ethyl acetate and dried at 50 °C under reduced pressure (50 mbar) for 5 hours. The dried product was then analyzed by XRPD, confirming identity of riociguat form I unequivocally.

Yield (dry): 3.224 g (0.0076 moles) = 75% for comparative example 2 and 72% overall (C.ex. 1 and 2). Total organic volatile impurity is higher than 1000 ppm and total DMSO content is higher than 100 ppm.

Example 1 ; Preparation of Riociguat ethylacetate solvate

Crude Riociguat (500 mg; Form I; 91 .7% percentage area purity) was dissolved in 2 ml DMF and heated to 100 °C to obtain a slightly turbid solution. After filtration through a 0.44 micron filter, 20 ml EtOAc were added to the hot solution (water bath 70°C) and allowed to stand. The temperature was slowly decreased to ambient temperature. Crystallization started after

10min. The yellowish, fine powder was filtered off and dried at ambient conditions. The PXRD indicated the formation of a new ethylacetate solvate. Yield 71 %, 97.8% purity.

Example 2; Preparation of the Methyl ethyl ketone (butan-2-one) solvate of Riociguat.

Crude Riociguat (500 mg; Form I; 91 .7% percentage area purity) was dissolved in 2 ml DMF at 100 °C to obtain a clear solution. After filtration through a 0.44 micron filter, 20 ml MEK were added. The hot solution (water bath 70 °C) was allowed stand. The temperature was then slowly decreased to ambient temperature. After 30 minutes yellowish, square-shaped crystals appeared, which were analyzed. Analysis confirmed that they were a new crystalline MEK-solvate. Yield 43%, 97.2% purity.

Example 3 ; Conversion of Solvated forms to Form I

Both the solvates from examples 1 and 2 can be converted to riociguat Form I by heating the material to 150°C under vacuum for an appropriate amount of time.

Example 4; Direct preparation of riociguat form I from crude riociguat using DMF-Acetone Crude Riociguat (200 mg; Form I; 91 .7% percentage area purity) was dissolved in 1.0 ml DMF at 100 °C to obtain a clear solution. After filtration through a 0.44 micron filter, 5 ml acetone was added. The hot solution (water bath 70 °C) was allowed to stand. Crystallisation occurred while the temperature was slowly decreased to ambient temperature. After 24 hours the precipitate was filtered off and dried at ambient conditions to obtain form I. Yield 78% ; 97.6% purity

///////////WO 2016113415, Sandoz, Riociguat, New Patent

Carbotegravir, Dolutegravir, New Patent, WO 2016113372, Lek Pharmaceutical and Chemical Co DD


WO 2016113372

Carbotegravir, New Patent, WO 2016113372, Lek Pharmaceutical and Chemical Co DD

LEK PHARMACEUTICALS D.D. [SI/SI]; Verovskova 57 1526 Ljubljana (SI)

MARAS, Nenad; (SI).
SELIC, Lovro; (SI).
CUSAK, Anja; (SI)

ViiV Healthcare is developing cabotegravir (first disclosed in WO2006088173), which in July 2016, was reported to be in phase 2 clinical development.

WO-2016113372

Process for preparing integrase inhibitors such as dolutegravir and cabotegravir and their analogs, useful for treating viral infections eg HIV infection. Also claims a process for preparing intermediates of dolutegravir and cabotegravir.

(4R, 12aS)-N-[(2,4-Difluorophenyl)methyl]-3 ,4,6,8, 12, 12a-hexahydro-7-hydroxy-4-methyl-6,8-dioxo-2H-pyrido[1 ‘,2’:4,5]pyrazino[2, 1-b][1 ,3]oxazine-9-carboxamide (Formula A):

Formula A

known by the INN name dolutegravir, is a new efficient antiviral agent from the group of HIV integrase inhibitors which is used in combination with some other antiviral agents for treatment of HIV infections, such as AIDS. The compound, which belongs to condensed polycyclic pyridines and was first disclosed in WO2006/1 16764, is marketed.

Another compound disclosed in WO2006/1 16764 is (3S, 1 1 aR)-N-[(2,4-difluorophenyl)methyl]-6-hydroxy-3-methyl-5,7-dioxo-2,3,5,7, 1 1 ,1 1 a-hexahydro[1 ,3]oxazolo[3,2-a]pyrido[1 ,2-d]pyrazine-8-carboxamide (Formula

Formula C

known by the INN name cabotegravir.

The complex structures of dolutegravir and cabotegravir present a synthetic challenge. The first description of the synthesis in WO2006/1 16764 shows a 16-steps synthesis (see Scheme A), which is industrially impractical due to its length and low overall yield.

Scheme A

WO 2010/068253 and WO 2006/1 16764 describe an alternative synthesis. The 1 1 -step synthesis, shown in Scheme B1 and Scheme B2, is based on bromination of the 9-position for further introduction of the carboxylic group. The synthesis relies on the use of expensive palladium catalysts and toxic selenium compounds. Furthermore, some variations of these approaches involve pyrone intermediates in several steps. In some cases pyrones are liquids which can complicate purification, while further reactions form complex mixtures.

doiutegravir

Scheme B2

In further alternative syntheses, acetoacetates were used as starting materials. Such an approach is challenging in terms of introducing the hydroxy group in the 7-position. The variation in Scheme C1 , described in WO2012/018065, starts from 4-benzyloxyacetoacetate. The procedure requires 9 steps, but use expensive reagents like palladium catalysts. Moreover, there is described a possibility of formation a co-crystal between an intermediate and hydroquinone, wherein however the additional step may diminish yields and make the process longer and time consuming.

Scheme C1

The variation in Scheme C2, described in WO2012/018065, starts from 4-chloroacetoacetate. The process is not optimal because of problems in steps which include pyrones and because of problems with conversion of 7-chloro to 7-hydroxy group which includes a disadvantageous use of silanolates with low yield (25%).

Scheme C2

The variation in Scheme C3, described in WO201 1/1 19566, starts from unsubstituted acetoacetate. For the introduction of the 7-hydroxy group, bromination is used and substitution of bromo with hydroxy is performed by a use of silanolates. The substitution of the bromine is achieved in a 43% yield.

Scheme C3

The variation in Scheme C4, described in WO201 1/1 19566, starts from 4-methoxyacetoacetate aiming at preparing dolutegravir or cabotegravir. The process uses lithium bases to affect a difficult to control selective monohydrolysis of a diester.

The object of the present invention is to provide short, simple, cost-effective, environmentally friendly and industrially suitable processes for beneficially providing dolutegravir and analogues thereof and cabotegravir and analogues thereof, in particular dolutegravir.

Scheme 1

According to an embodiment of the process of the invention the building block 3-aminobutanol can suitably be substituted with other aminoalcohols to give dolutegravir analogues. For example, using (S)-alaninol gives cabotegravir as the final product. Similarly, using amines other than 2,4-difluorobenzylamine in the amidation step results in the synthesis of other dolutegravir analogues.

According to the another preferred embodiment cabotegravir or a pharmaceutically acceptable salt thereof is prepared by the analogue process, which comprises providing a compound of formula (5c)

5c

converting the compound of formula (5c) to a compound of formula (6c)

6c

by carrying out a chlorination reaction, and converting the compound of formula (6c) to cabotegravir and/or a pharmaceutically acceptable salt thereof.

The compound of formula (5c) can preferably be provided by converting a compound of formula (3) to a compound of formula (4c)

Scheme 2

1. ) EtOCOCI, Et3N / Me2CO

2. ) 2,4-difiuorobenzylamine

Scheme 3

Analogous compound of formula 7c is a useful intermediate in the synthesis of cabotegravir. Scheme 3a

Scheme 4

Examples

The following examples are merely illustrative of the present invention and they should not be considered as limiting the scope of the invention in any way. The examples and modifications or other equivalents thereof will become apparent to those versed in the art in the light of the present entire disclosure. Particularly, all Examples related to the preparation of dolutegravir and intermediates thereof can be used by the analogy for the preparation of cabotegravir and intermediates thereof.

Example 1 :

Methyl acetoacetate (1 , 25.22 g) and dimethylformamide dimethyl acetal (DMFDMA, 35 mL) was heated at 50-55°C for 2 h, then methanol (60 mL), aminoacetaldehyde dimethyl acetal (24 mL) and acetic acid (4 mL) was added an the mixture was heated under reflux for one hour, then concentrated. MTBE (100 mL) was added and the mixture was kept at 5 °C overnight to crystallize. Upon filtration 46 g (92%) of product 2 was recovered.

1H NMR (DMSO-d6): δ 2.31 (s, 3H), 3.30 (s, 6H), 3.49 (m, 2H), 3.61 (s, 3H), 4.43 (m, 1 H), 8.02 (d, 1 H), 10.8 (bs, 1 H). 13C NMR (DMSO-d6): δ 30.52, 35.48, 50.53, 54.23, 98.99, 102.47, 160.70, 166.92, 197.21 .

Example 2:

Compound 2 (5.00 g) was dissolved in 2-propanol, dimethyl oxalate (7.02 g) was added and heated to 40 °C. Sodium methylate (25% in methanol; 20 mL) was slowly (10 min) added, the mixture was then heated to 50-55 °C and stirred at that temperature for 2-2.5 h. The mixture was cooled to ambient temperature, then sodium hydroxide solution (1 M, 65 mL) was added to the mixture and stirred for another 2 h, followed by addition of concentrated hydrochloric acid (1 1 mL) and stirred for another 2 h. The precipitate was filtered and dried to give 8.08 g (NMR assay 47%; 65% yield) of compound 3.

1H NMR (DMSO-d6): δ 2.50 (m, 2H), 3.30 (s. 6H), 4.49 (m, 1 H), 7.06 (s, 1 H); 8.70 (s, 1 H). 13C NMR (DMSO-d6): δ 55.23, 55.37, 102.34, 1 15.47, 120.24, 145.17, 162.71 , 165.22, 178.55.

Example 3:

Compound 2 (158.37 g) was dissolved in methanol (548 mL), followed by the addition of dimethyl oxalate (202.2 g). While keeping the temperature below 30°C, potassium ferf-butoxide (192.1 g) was added and reaction mixture was heated at 50 °C overnight. The suspension was then filtered and the filter cake washed with methanol. The filtrate was concentrated (approximately to 680 mL), then water (680 mL) was added, followed by addition of lithium hydroxide hydrate (143.7 g) while keeping the temperature below 40 °C. The suspension was then stirred at ambient temperature overnight and filtered. To the obtained filtrate, concentrated hydrochloric acid (339 mL) was added while keeping the temperature below 30 °C. The suspension was aged for 2 h and filtered to give 4 as a white powder (95.6 g, NMR assay 100%; 52% yield).

Example 4:

Compound 2 (5.00 g) was dissolved in 2-propanol, dimethyl oxalate (7.02 g) was added and heated to 40 °C. Sodium methylate (25% in methanol; 15 mL) was slowly (10 min) added then the mixture was heated to 50-55 °C and stirred at that temperature for 72 h. The mixture was concentrated and components were separated by flash column chromatography (ethyl acetate/methanol 9:1 to 6:4). Early fractions gave compound 22 upon concentration, late fractions gave compound 23.

Compound 22: 1H NMR (DMSO-d6): δ 2.49 (m, 2H), 3.28 (s, 6H), 3.73 (s, 3H), 3.85 (s, 3H), 4.41 (m, 1 H), 4.50 (m, 1 H), 6.65 (s, 1 H), 8.36 (s, 1 H). 13C NMR (DMSO-d6): δ 51.63, 53.36, 54.25, 55.47, 102.71 , 1 18.24, 123.60, 140.81 , 150.21 , 162.44, 164.49, 173.43.

Compound 23: 1H NMR (DMSO-d6): δ 2.49 (m, 2H), 3.26 (s, 6H); 3.70 (s, 3H); 4.33 (d, 1 H); 4.60 (m, 1 H), 6.19 (s, 1 H), 8.12 (s, 1 H). 13C NMR (DMSO-d6): δ 50.03, 51.34, 54.59, 54.85, 102.91 , 1 16.04, 1 18.19, 148.32, 152.12, 163.46, 165.24, 174.99

Example 5:

Compound 3 (5.5 g; assay 53%) was suspended in acetonitrile, acetic acid (6 mL) and methanesulfonic acid (2.5 mL) were added followed by the heating of mixture to 70 °C for 4 h. The suspension was filtered and filtrate cooled to ambient temperature. Triethylamine (6.6 mL) and (R)-3-amino-butan-1 -ol (1.24 mL) was added followed by heating the mixture at reflux temperature for 20-24 h. The mixture was filtered, filtrate concentrated and 1 M HCI (100 mL) was added, followed by extraction with dichloromethane (3 x 50 mL). Combined organic fractions were concentrated, 2-propanol was added (10 mL) and suspension was stirred at 70-80 °C for 10 min, left to cool to ambient temperature then filtered to give 2.19 g of compound 4 (73%).

1H NMR (DMSO-de): δ 1.31 (d, 3H), 1.52 (m, 1 H), 1 .97 (m, 1 H), 3.89 (m, 1 H), 4.01 (m, 1 H), 4.46 (m, 1 H), 4.64 (m, 1 H), 4.78 (m, 1 H), 5.50 (m, 1 H), 7.29 (s, 1 H), 8.88 (s, 1 H), 15.83 (s, 1 H). 13C NMR (DMSO-d6): δ 15.22, 29.14, 45.26, 51.13, 62.09, 76.03, 1 16.31 , 1 18.79, 140.53, 146.79, 155.36, 165.24, 178.75.

Example 6:

Compound 3 (14.55 g; assay 49%) was suspended in acetonitrile (125 mL), acetic acid (15 mL) and methanesulfonic acid (6.25 mL) were added followed by the heating of mixture to 70 °C for 4 h. The suspension was filtered and filtrate cooled to ambient temperature. Triethylamine (16.5 mL) and (S)-2-aminopropanol (2.45 mL) was added followed by heating the mixture at reflux temperature for 24 h. The insoluble product was filtered, washed with 2-propanol (20 mL) and dried to give (3S, 1 1 aR)-3-methyl-5,7-dioxo-2,3,5,7, 1 1 ,1 1 a-hexahydrooxazolo[3,2-a]pyrido[1 ,2-d]pyrazine-8-carboxylic acid (5.2 g, 75%).

1H NMR (DMSO-d6): δ 1.31 (d, J = 6.3 Hz, 3H), 3.65 (dd, J = 8.6, 6.8 Hz, 1 H), 4.13 (dd, J = 1 1.7, 10.3 Hz, 1 H), 4.28 (m, 1 H), 4.39 (dd, J = 8.6, 6.8 Hz, 1 H), 4.92 (dd, J = 12.3, 4.2 Hz, 1 H), 5.45 (dd, J = 10.2, 4.1 Hz, 1 H), 7.16 (s, 1 H), 8.84 (s, 1 H), 15.74 (s, 1 H).

Example 7:

Compound 4 (0.63 g) was dissolved in dichloromethane (15 mL), cooled to 5°C, then triethylamine (0.31 mL) was added, followed by ethyl chloroformate (0.26 mL), followed by slow (30 min) addition of 2,4-difluorobenzylamine. The mixture was then stirred at ambient temperature for 24 h. Water (10 mL) was added, organic phase was separated and washed with 1 M HCI (15 mL) and water (15 mL), concentrated and treated with 2-propanol to give the product 5 in a quantitative yield.

1H NMR (CDCI3): δ 1.39 (d, 3H), 1.52 (s, 1 H), 2.19 (m, 1 H), 4.00 (m, 2H), 4.16 (m, 1 H), 4.31 (m, 1 H), 4.62 (d, 2H), 5.00 (m, 1 H), 5.27 (m, 1 H), 6.80 (m 2H), 7.33 (m, 2H), 8.49 (s, 1 H), 10.48 (s, 1 H). 13C NMR (CDCI3): 15.50, 29.22, 36.43, 45.19, 51.83, 62.79, 103.71 , 103.91 , 1 1 1 .0, 1 1 1 .18, 120.59, 123.04, 130.40, 137.41 , 144.58, 156.27, 163. 87, 177.83.

Example 8:

To a suspension of 4 (2.84 g, 10 mmol) in a mixture of triethylamine (2.24 mL, 16 mmol) and acetone (50 mL) stirring on an ice bath was added ethyl chloroformate (1 .20 mL, 12 mmol). After stirring for 10 min, 2,4-difluorobenzylamine (1.21 mL, 10 mmol) was added and the mixture left stirring at room temperature for 1 h. The product was isolated by slowly diluting the reaction mixture with water (50 mL), partial concentration, filtration, washing with water (2 50 mL) and drying. There was obtained 5 as a white powder (3.48 g, 86%): mp 181.0-184.7 °C. 1H NMR (DMSO-d6): δ 1.29 (d, J = 7.0 Hz, 3H), 1 .56 (dd, J = 13.9, 2.0 Hz, 1 H), 1 .93-2.06 (m, 1 H), 3.90 (ddd, J = 1 1.6, 5.0, 2.1 Hz, 1 H), 3.98 (td, J = 12.0, 2.2 Hz, 1 H), 4.45 (dd, J = 13.6, 6.6 Hz, 1 H), 4.72 (dd, J = 13.6, 3.8 Hz, 1 H), 4.74-4.81 (m, 1 H), 5.44 (dd, J = 6.6, 3.8 Hz, 1 H), 8.93 (s, 1 H), 15.14 (s, 1 H). 13C NMR (DMSO-d6): δ 15.78, 29.13, 44.89, 52.88, 61 .63, 75.61 , 1 13.54, 128.49, 136.42, 145.64, 154.62, 164.58, 174.58

Example 9:

To a suspension of 4 (1 1.36 g, 40 mmol) in acetonitrile (80 mL) stirring at room temperature was added TCCA (9.29 g, 38 mmol) and DABCO (0.23 g, 5 mol%). After stirring at room temperature for 1 h, the reaction was quenched with a mixture of DMSO (5.26 mL) and water (1.33 mL). The insoluble cyanuric acid was removed by filtration and the filtrate evaporated under reduced pressure to give viscous oil. This was triturated in methanol (20 mL) to induce crystallization. The product was filtered, washed with cold methanol (10 mL) and dried to give 7 as a yellowish powder (5.13 g, 41 %): mp 191 .3-198.7 °C.

Example 10:

Attempted chlorination of 23: Compound 23 (0.54g) was suspended in acetonitrile (10 mL) and trichlorocyanuric acid (0.44 g) was added and the solution was stirred at ambient temperature overnight. Precipitate was filtered. Only traces of a product corresponding to the compound 26 could be detected in the reaction mixture by LC-MS analysis. Conversion did not improve with time.

Example 11 :

Attempted chlorination of 3: Compound 3 (0.30 g) was suspended in acetonitrile (5 mL) and trichlorocyanuric acid (0.13 g) was added. The suspension was stirred at ambient temperature overnight. Only traces of a product corresponding to the compound 24 could be detected in the reaction mixture by LC-MS analysis.

Example 12:

9 10

Trichloroisocyanuric acid (0.23 g) was added in a single portion to a stirred solution of the diethyl 1 -(2,2-dimethoxyethyl)-4-oxo-1 ,4-dihydropyridine-2,5-dicarboxylate (9, 0.66 g) in dry acetonitrile (4 mL) at room temperature. The resulting suspension was stirred at room temperature for ca. 24 h. The reaction mixture was diluted with dichloromethane and filtrated. The filtrate was then concentrated in vacuo to afford crude oil (0.86 g). Purification by flash chromatography (eluting ethyl acetate/cyclohexane) furnished diethyl 3-chloro-1 -(2,2-dimethoxyethyl)-4-oxo-1 ,4-dihydropyridine-2,5-dicarboxylate, 10 as a yellow semi-solid (0.38 g). 1H NMR (CDCI3): δ 1.28 (t, J=7A Hz, 3H), 1 .37 (t, J=7.2 Hz, 3H), 3.35 (s, 6H), 3.89 (d, J=5.0 Hz, 2H), 4.27 (q, J=l A Hz, 2H), 4.43 (q, J=l A Hz, 2H), 4.48 (t, J=4.9 Hz, 1 H), 8.15 (s, 1 H). 13C NMR (CDCI3): δ 13.83, 14.13, 55.82, 57.09, 61.41 , 63.72, 102.52, 1 17.35, 126.90, 140.22, 146.92, 160.67, 164.13, 168.95.

Example 13:

Diethyl 1 -(2,2-dimethoxyethyl)-4-oxo-1 ,4-dihydropyridine-2,5-dicarboxylate (9, 0.64 g) was dissolved in anhydrous acetonitrile (6 mL) and treated sequentially with acetic acid (560 μί) and methanesulfonic acid (40 μί). The resulting mixture was heated to 62 °C and stirred for 4 h and more methanesulfonic acid (40 μΙ_) was added. After additional 2 h, more methanesulfonic acid (80 μΙ_) was added. This was repeated after additional 2 h, when more methanesulfonic acid (80 μΙ_) was added. The reaction mixture was stirred additional 17 h at 62 °C then was treated with a mixture of (R)-3-aminobutanol (0.22 g), triethylamine (0.5 mL) and acetonitrile (0.7 mL). The reaction mixture was stirred additional 22 h at 62 °C and then concentrated in vacuo. The crude material was partitioned between dichloromethane and 1 M HCI solution (15 mL). The combined organic phases were dried (Na2S04), filtered and concentrated in vacuo to afford the crude (4R, 12aS)-ethyl 4-methyl-6,8-dioxo-3,4,6,8, 12,12a-hexahydro-2H-pyrido[1 ‘,2’:4,5]pyrazino[2, 1 -b][1 ,3]oxazine-9-carboxylate (11 ) as a brownish oil (0.61 g).

1H NMR (CD3OD): δ 8.44 (s, 1 H), 7.16 (m, 1 H), 5.48 (t, J=4.8 Hz, 1 H), 4.86 (m, 1 H), 4.49 (dd, J=13.6, 4.0 Hz, 1 H), 4.30-4.25 (m, 3H), 4.09 (dt, J=12.1 , 2.3 Hz, 1 H), 3.96 (ddd, J=1 1.7, 5.0, 2.1 Hz, 1 H), 2.18-2.10 (m, 1 H), 1.60-1 .56 (m, 1 H) 1 .39 (d, J=7A Hz, 3H), 1.33 (t, J=7A Hz, 3H). 13C NMR (CDCI3): δ 8.45, 14.08, 15.39, 29.17, 45.04, 45.72, 51 .56, 60.86, 62.61 , 76.33, 1 19.54, 123.72, 136.96, 145.67, 156.26, 163.68, 175.43

Example 14:

10

Diethyl 3-chloro-1 -(2,2-dimethoxyethyl)-4-oxo-1 ,4-dihydropyridine-2,5-dicarboxylate (10, 1.23 g) was dissolved in 85% formic acid (25 mL) at room temperature. The mixture was warmed to 40 °C and stirred for 23 h. The reaction mixture was concentrated in vacuo, and then partitioned between dichloromethane and aqueous NaHC03 solution. The combined organic phases were dried (Na2S04), filtered and concentrated in vacuo to afford brownish oil (0.49 g). The crude oil was dissolved in anhydrous toluene (5 mL) and treated sequentially with (R)-3-aminobutanol (0.19 g), methanol (0.2 mL) and acetic acid (96 μί). The resulting mixture was heated to 90 °C and stirred for 20 h. The reaction mixture was cooled to room temperature and then partitioned between dichloromethane and aqueous NaHC03 solution. The combined organic phases were dried (Na2S04), filtered and concentrated in vacuo to afford the crude (4R,12aS)-Ethyl 7-chloro-4-methyl-6,8-dioxo-3,4,6,8,12, 12a-hexahydro-2H-pyrido[1 ‘,2’:4,5] pyrazino [2, 1-b][1 ,3]oxazine-9-carboxylate (12) as a brownish oil (0.24 g).

Example 15:

To a solution of 4 (5.68 g, 20 mmol) in dichloromethane (50 mL) stirring in an ice bath was added triethylamine (5.6 mL, 40 mmol), followed by ethyl chloroformate (2.61 mL, 26 mmol). After 20 min, ethanol (50 mL) was added. The mixture was then left stirring 24 h at room temperature and concentrated under reduced pressure. The residue was triturated in acetone (80 mL). The insoluble salt (triethylamine hydrochloride) was removed by filtration. The filtrate was evaporated under reduced pressure to give 11 as an amorphous solid in a quantitative yield (6.1 g).

Example 16:

To a stirring solution of 11 (0.94 g, 3.0 mmol) in acetonitrile (8 mL) heated at 40 °C was added TCCA in portions during 1 h (0.44 g, 1 .8 mmol). After an additional 1 h, the reaction mixture was diluted with a solution of NaHS03 (0.60 g) in water (60 mL), extracted with dichloromethane (50 mL) and the extract evaporated under reduced pressure to give a crude product which was purified by flash chromatography (CH2CI2 : MeOH, from 98 : 2 to 80 : 20) to give 12 (0.45 g, 44%).

1H NMR (CDCI3): δ 1.37 (t, J = 7.1 Hz, 3H), 1.38 (d, J = 7.0 Hz, 3H), 1 .56 (dq, J = 13.9, 2.2 Hz, 1 H), 2.21 (m, 1 H), 3.99 (d, J = 2.3 Hz, 1 H), 4.00 (t, J = 1.8 Hz, 1 H), 4.10 (dd, J = 13.2, 6.6 Hz, 1 H), 4.37-4.27 (m, 3H), 4.98 (m, 1 H), 5.35 (dd, J = 6.6, 3.8 Hz, 1 H), 8.07 (s, 1 H).

13C NMR (CDCI3): δ 14.20, 16.09, 29.34, 44.87, 53.73, 61.49, 62.29, 76.01 , 1 16.22, 133.1 1 , 134.18, 144.52, 155.48, 163.88, 169.98.

Example 17:

To a mixture of 7 (3.89 g, 12.2 mmol) in methanol (12 mL) was added sodium methylate (22.3 mL, 97.6 mmol). The reaction mixture was stirred for 24 h at 30 °C and then quenched with a slow addition of 3M hydrochloric acid (35 mL) while stirring in an ice bath. The mixture was concentrated under reduced pressure to remove most of the methanol, then extracted with dichloromethane (2 30 mL), the combined extracts washed with water (30 mL) and evaporated under reduced pressure. Methanol (20 mL) was added to the obtained amorphous residue and removed under reduced pressure to yield the solid 8 (3.69 g, 98%).

1H NMR (CDCI3): δ 15.04 (s, 1 H), 8.42 (s, 1 H), 5.29 (dd, J=5.6, 3.9 Hz, 1 H), 5.01 -4.96 (m, 1 H), 4.42 (dd, J=13.6, 3.6 Hz, 1 H), 4.25 (dd, J=13.6, 6.0 Hz, 1 H), 4.05 (s, 3H), 4.00-3.97 (m, 2H), 2.21 -2-14 (m, 1 H), 1.53 (dd, J=14.1 , 1.9 Hz, 1 H), 1.36 (d, J=7 Hz, 3H). 13C NMR (CDCI3): δ 176.35, 165.94, 155.03, 153.70, 143.08, 130.90, 1 15.94, 76.05, 62.65, 61.45, 53.86, 44.96, 29.43, 16.06.

Example 18:

To a suspension of 7 (2.55 g, 8.0 mmol) in a mixture of triethylamine (1 .46 mL, 10.4 mmol) and acetone (32 mL) stirring on an ice bath was added ethyl chloroformate (0.88 mL, 8.8 mmol). After stirring for 10 min, 2,4-difluorobenzylamine (1.07 mL, 8.8 mmol) was added and the mixture left stirring at room temperature for 1 h. The product was isolated by slowly diluting the reaction mixture with water (40 mL), filtration, washing with water (2 30 mL) and drying. There was obtained 2.91 g of 6 as a white powder (83%).

1H NMR (CDCI3): δ 1.30 (d, J = 7.0 Hz, 3H), 1 .49 (dd, J = 14.0, 2.2 Hz, 1 H), 2.14 (ddd, J = 14.6, 1 1.1 , 6.4 Hz, 1 H), 3.89-3.95 (m, 2H), 4.09-4.15 (m, 1 H), 4.26 (dd, J = 13.4, 3.8 Hz, 1 H), 4.55 (d, J = 5.8 Hz, 2H), 4.89-4.98 (m, 1 H), 5.18 (dd, J = 6.2, 3.8 Hz, 1 H), 6.68-6.79 (m, 2H), 7.23-7.31 (m, 1 H), 8.41 (s, 1 H), 10.24 (t, J = 5.8 Hz, 1 H). 13C NMR (CDCI3): δ 16.09, 26.95, 29.30, 36.79, 45.1 1 , 45.28, 53.86, 62.47, 75.93, 103.87 (t, J = 25.4 Hz), 1 1 1 .21 (dd, J = 21 .0, 3.4 Hz), 1 17.32, 130.58 (dd, J = 9.3, 5.8 Hz), 133.40, 143.54, 155.34, 163.16, 163.25, 163.35, 172.88.

Example 19:

To a suspension of 5 (1 .67 g, 4 mmol) in acetonitrile (20 mL) was added DABCO (23 mg, 5 mol%) and TCCA (0.62 g, 2.52 mmol). The mixture was stirred 18 h at 40 °C protected from light and then quenched with a mixture of DMSO (0.48 mL) and water (0.12 mL). The insoluble cyanuric acid was removed by filtration and washed with acetonitrile (5 mL). The filtrate was evaporated under reduced pressure to give viscous oil that was crystallized from a mixture of methanol (6 mL) and water (3 mL), by slowly cooling the solution from 60 °C to room

temperature. The product 6 was filtered, washed with cold methanol (5 mL) and dried to give an off-white powder (1.07 g, 61 %).

1H NMR (CDCI3): δ 1.30 (d, J = 7.0 Hz, 3H), 1 .49 (dd, J = 14.0, 2.2 Hz, 1 H), 2.14 (ddd, J = 14.6, 1 1.1 , 6.4 Hz, 1 H), 3.89-3.95 (m, 2H), 4.09-4.15 (m, 1 H), 4.26 (dd, J = 13.4, 3.8 Hz, 1 H), 4.55 (d, J = 5.8 Hz, 2H), 4.89-4.98 (m, 1 H), 5.18 (dd, J = 6.2, 3.8 Hz, 1 H), 6.68-6.79 (m, 2H), 7.23-7.31 (m, 1 H), 8.41 (s, 1 H), 10.24 (t, J = 5.8 Hz, 1 H). 13C NMR (CDCI3): δ 16.09, 26.95, 29.30, 36.79, 45.1 1 , 45.28, 53.86, 62.47, 75.93, 103.87 (t, J = 25.4 Hz), 1 1 1 .21 (dd, J = 21.0, 3.4 Hz), 1 17.32, 130.58 (dd, J = 9.3, 5.8 Hz), 133.40, 143.54, 155.34, 163.16, 163.25, 163.35, 172.88.

Example 20:

To a suspension of 6 (0.44 g) in anhydrous methanol (1 mL) was added a 25% methanolic solution of sodium methylate (1 .14 mL) and the mixture stirred for 4 h at 40 °C. The reaction was quenched with acetic acid (0.4 mL), diluted with water (8 mL), extracted with 2-methyltetrahydrofuran (12 mL), the extract washed with 1 M NaOH(aq) (8 mL), water (8 mL) and evaporated under reduced pressure. To the oily residue was added methanol (8 mL) and evaporated under reduced pressure to give 27 as a white solid (0.38 g, 88%).

Example 21 :

The suspension of (4R, 12aS)-7-chloro-N-(2,4-difluorobenzyl)-4-methyl-6,8-dioxo-3,4,6,8,12, 12a-hexahydro-2H-pyrido[1 ‘,2’:4,5]pyrazino[2, 1 -b][1 ,3]oxazine-9-carboxamide (6, 0.44 g) and solid sodium hydroxide (0.20 g) in absolute ethanol (2 mL) was stirred at room temperature for 24 h. The reaction was quenched with 2M H2S04 (1 .18 mL) and left stirring for 2 h at room temperature. The reaction mixture was filtered through fitted funnel rinsing with water (2 x 2 mL). The obtained white precipitate (0.38 g) was suspended in THF-water (1 :1 , 4.5 mL) and stirred at room temperature for ca. 2 h. The reaction mixture was filtered through fitted funnel rinsing with water (2 χ 1 mL) and dried in vacuo at 40°C to afford pure dolutegravir as a white solid (0.33 g, HPLC purity: 99.38%).

1H NMR (DMSO-d6): δ 12.51 (s, 1 H), 10.36 (t, J=5.9 Hz, 1 H), 8.50 (s, 1 H), 7.41-7.36 (m, 1 H), 7.26-7.21 (m, 1 H), 7.07-7.03 (m, 1 H), 5.45 (dd, J=5.4, 4.3 Hz, 1 H), 4.81 -4.76 (m, 1 H), 4.59-4.53 (m, 3H), 4.36 (dd, J=13.8, 5.8 Hz, 1 H), 4.05-4.00 (m, 1 H), 3.91-3.88 (m, 1 H), 2.05-1 .97 (m, 1 H), 1.55-1.52 (m, 1 H), 1 .33 (d, J=7.1 Hz, 3H). 13C NMR (DMSO-d6): δ 170.27, 163.68, 162.29, 161 .78 (dd), 159.82 (dd), 154.61 , 140.64, 130.74 (d), 130.67 (d), 122.37 (d), 1 16.73, 1 15.38, 1 1 1 .33 (d), 103.80 (t), 62.01 , 51 .16, 44.69, 35.74, 29.13, 15.21.

Example 22:

A suspension of dolutegravir (0.31 g) in methanol (4 mL) was cooled to 0 °C.25% Solution of sodium methoxide in methanol was added to the mixture and the resulting suspension was stirred at 0 °C for 2 h, then at room temperature for 23 h. The reaction mixture was then filtered through fitted funnel rinsing with methanol (3 x 10 mL). The white precipitate was dried overnight at room temperature to afford pure dolutegravir sodium as a white solid (0.26 g, HPLC purity: 99.84%).

1H NMR (DMSO-d6): δ 10.70 (t, J=5.8, 1H), 7.89 (s, 1H), 7.37-7.30 (m, 1H), 7.23-7.19 (m, 1H), 7.04-7.01 (m, 1H), 5.17 (m, 1H), 4.81 (t, J=6.4Hz, 1H), 4.51 (d, J=5.5Hz, 2H), 4.32-4.29 (m, 1H), 4.16 (dd, J=14.1, 4.8 Hz, 1H), 3.99-3.94 (m, 1H), 3.82-3.80 (m, 1H), 1.89-1.84 (m, 1H), 1.38 (d, J=12.9 Hz, 1H), 1.24 (d, J=7.0Hz, 3H).13C NMR (DMSO-d6): δ 177.93, 167.12, 166.08, 161.59 (dd), 161.13, 159.63 (dd), 134.26, 130.44 (d), 130.38 (d), 122.90 (d), 114.95, 111.23 (d), 108.78, 103.64 (t), 75.59, 61.95, 53.11, 43.01, 35.32, 29.22, 15.30.

Example 23:

The suspension of 6 (0.44 g) and solid sodium hydroxide (0.20 g) in absolute ethanol (2 mL) was stirred at room temperature for 24 h. The reaction was diluted with absolute ethanol (10 mL) and left stirring for ca. 30 min at room temperature. The reaction mixture was filtered through fitted funnel rinsing with absolute ethanol (3 x 10 mL) and dried in vacuo at room temperature to afford dolutegravir sodium as a pale yellow solid (0.43 g, HPLC purity: 98.80%). 1H NMR (DMSO-d6): δ 10.70 (t, J = 5.8 Hz, 1H), 7.89 (s, 1H), 7.37-7.30 (m, 1H), 7.23-7.19 (m, 1H), 7.04-7.01 (m, 1H), 5.17 (m, 1H), 4.81 (t, J = 6.4 Hz, 1H), 4.51 (d, J = 5.5 Hz, 2H), 4.32-4.29 (m, 1H), 4.16 (dd, J= 14.1, 4.8 Hz, 1H), 3.99-3.94 (m, 1H), 3.82-3.80 (m, 1H), 1.89-1.84 (m, 1H), 1.38 (d, J = 12.9 Hz, 1H), 1.24 (d, J = 7.0 Hz, 3H).13C NMR (DMSO-d6): δ 177.93, 167.12, 166.08, 161.59 (dd), 161.13, 159.63 (dd), 134.26, 130.44 (d), 130.38 (d), 122.90 (d), 114.95, 111.23 (d), 108.78, 103.64 (t), 75.59, 61.95, 53.11, 43.01, 35.32, 29.22, 15.30.

Example 24:

The suspension of (4R,12aS)-N-(2,4-difluorobenzyl)-7-methoxy-4-methyl-6,8-dioxo-3,4,6,8,12, 12a-hexahydro-2H-pyrido[1′,2′:4,5]pyrazino[2,1-6][1,3]oxazine-9-carboxamide (27, 0.43 g) and solid sodium hydroxide (0.20 g) in absolute ethanol (2.5 mL) was stirred at room temperature for ca.24 h. The reaction was diluted with mixture of water/ethanol (5 mL, 1:1) and left stirring for ca. 1.5 h at room temperature. The reaction mixture was filtered through fitted funnel rinsing with mixture of water/ethanol (3 x 5 mL, 1:1) and dried in vacuo at room temperature to afford 15 as a pale yellow solid (0.41 g, HPLC purity: 98.87%).

1H NMR (DMSO-de): δ 10.70 (t, J = 5.8 Hz, 1H), 7.89 (s, 1H), 7.37-7.30 (m, 1H), 7.23-7.19 (m, 1H), 7.04-7.01 (m, 1H), 5.17 (m, 1H), 4.81 (t, J = 6.4 Hz, 1H), 4.51 (d, J = 5.5 Hz, 2H), 4.32-4.29 (m, 1H), 4.16 (dd, J = 14.1, 4.8 Hz, 1H), 3.99-3.94 (m, 1H), 3.82-3.80 (m, 1H), 1.89-1.84 (m, 1H), 1.38 (d, J = 12.9 Hz, 1H), 1.24 (d, J = 7.0 Hz, 3H).13C NMR (DMSO-d6): δ 177.93, 167.12, 166.08, 161.59 (dd), 161.13, 159.63 (dd), 134.26, 130.44 (d), 130.38 (d), 122.90 (d), 114.95, 111.23 (d), 108.78, 103.64 (t), 75.59, 61.95, 53.11, 43.01, 35.32, 29.22, 15.30.

Example 25:

The suspension of {4R, 12aS)-7-chloro-4-methyl-6,8-dioxo-3,4, 6,8, 12,12a-hexahydro-2H-pyrido[1′,2′:4,5]pyrazino[2,1-6][1,3]oxazine-9-carboxylic acid (7, 0.31 g) and solid sodium hydroxide (0.20 g) in absolute ethanol (2.5 mL) was stirred at 50 °C for 3 days. The reaction was quenched with 2M H2S04 (1.2 mL) and left stirring for 7 h at room temperature. The reaction mixture was filtered through fitted funnel rinsing with water (3×5 mL) and ethanol (5 mL) dried in vacuo at 40°C to afford 28 as a pale yellow solid (0.17 g).

1H NMR (DMSO-d6): δ 15.37 (s, 1H), 12.76 (s, 1H), 8.66 (s, 1H), 5.51-5.49 (m, 1H), 4.80-4.78 (m, 1H), 4.65 (dd, J=13.8, 3.7 Hz, 1H), 4.43 (dd, J=13.8, 5.9 Hz, 1H), 4.05 (t, J^^.b Hz, 1H), 3.91 (dd, J=11.4, 3.1 Hz, 1H), 2.07-2.00 (m, 1H), 1.56 (d, J=13.8 Hz, 1H), 1.34 (d, J=7.0 Hz, 3H).13C NMR (DMSO-de): δ 172.21, 165.39, 161.73, 153.61, 141.11, 118.66, 112.99, 75.95, 62.03, 51.50, 44.90, 29.08, 15.18.

Example 26:

The suspension of (4R,12aS)-N-(2,4-difluorobenzyl)-7-methoxy-4-methyl-6,8-dioxo-3,4,6,8, 12, 12a-hexahydro-2H-pyrido[1 ‘,2’:4,5]pyrazino[2, 1 ,3]oxazine-9-carboxamide (27, 0.88 g) and solid sodium hydroxide (0.24 g) in absolute ethanol (20 mL) was stirred at 30 °C for 1.5 h. The reaction was quenched with 2M H2S04 (1 .5 mL) and left stirring for 3 hours at room temperature. The reaction mixture was filtered through fritted funnel and rinsed with water (3 x 2 mL) and ethanol (4 mL), and dried in vacuo at 40 °C to afford O-ethyl dolutegravir (29) as a pale yellow solid (0.25 g). The filtrate was extracted with ethyl acetate (3 x 5 mL). The combined organic layers were dried over MgS04, filtered and concentrated, then dried in vacuo at 40 °C to afford more 29 as a pale yellow solid (0.27 g).

1H NMR (CDCI3): δ 10.37 (t, J = 5.8 Hz, 1 H), 8.36 (s, 1 H), 7.37-7.32 (m, 1 H), 6.83-6.77 (m, 2H), 5.19 (dd, J = 5.9, 3.8 Hz, 1 H), 5.04-4.98 (m, 1 H), 4.61 (d, J = 6Hz, 2H), 4.26-4.22 (m, 3H), 4.1 1 (dd, J = 13.4, 5.9 Hz, 1 H), 3.97 (t, J = 2.4 Hz, 1 H), 3.96 (d, J = 2.4 Hz, 1 H), 2.21-2.14 (m, 1 H), 1.51 (dq, J = 14.0, 2.3 Hz, 1 H), 1 .47 (t, J = 7.0 Hz, 3H), 1 .35 (d, J = 7.1 Hz, 3H).

13C NMR (CDCI3): δ 174.78, 164.17, 162.49 (dd), 160.51 (dd), 155.72, 154.08, 142.32, 130.60 (dd), 129.33, 121 .51 (dd), 1 18.67, 1 1 1 .23 (dd), 103.78 (t), 76.15, 69.74, 62.58, 53.42, 44.58, 36.50 (d), 29.44, 16.04, 15.64.

Example 27:

The suspension of (4R, 12aS)-7-(benzyloxy)-4-methyl-3,4, 12,12a-tetrahydro-2H-pyrido[1 ‘,2’:4,5]pyrazino[2, 1-b][1 ,3]oxazine-6,8-dione (30, 0.68 g, prepared according to prior art) and solid sodium hydroxide (0.40 g) in absolute ethanol (5 mL) was stirred at 50 °C for 14 h. The reaction was quenched with formic acid (0.35 mL), water (2 mL) was added and mixture was left stirring for additional 1 h at room temperature. The reaction mixture was extracted with ethyl acetate (3 x 5 mL) and the combined organic layers concentrated to afford a crude oil. Purification by flash chromatography (eluting with CH2CI2/methanol) afforded 32 as an orange solid (0.26 g, 52 %).

The above procedure if done at room temperature in same time period, affords 31 as orange oil (0.24 g, 43 %).

Compound 32: 1H NMR (DMSO-d6): δ 7.64 (d, J = 7.4 Hz, 1 H), 6.20 (d, J = 7.3 Hz, 1 H), 5.40 (dd, J = 5.1 , 4.2 Hz, 1 H), 4.83-4.78 (m, 1 H), 4.35 (dd, J = 13.6, 3.9 Hz, 1 H), 4.13 (dd, J = 13.6, 5.4 Hz, 1 H), 4.05-4.00 (m, 1 H), 3.90-3.85 (m, 1 H), 2.03-1.95 (m, 1 H), 1.52 (dd, J = 13.9, 1 .9 Hz, 1 H), 1.33 (d, J = 7.1 Hz, 3H). 13C NMR (DMSO-d6): δ 170.96, 163.01 , 153.48, 137.96, 1 16.83, 1 13.52, 76.18, 62.05, 50.39, 44.53, 29.21 , 15.28.

Compound 31 : 1H NMR (DMSO-d6): δ 7.67 (d, J = 7.4 Hz, 1 H), 6.28 (d, J = 7.4 Hz, 1 H), 5.29 (dd, J = 5.4, 3.8 Hz, 1 H), 4.82-4.75 (m, 1 H), 4.32 (dd, J = 13.6, 3.6 Hz, 1 H), 4.10 (dd, J = 13.5, 5.6 Hz, 1 H), 4.03-3.93 (m, 3H), 3.85 (ddd, J = 1 1 .6, 5.0, 2.2 Hz, 1 H), 1.97-1 .89 (m, 1 H), 1 .48 (dd, J = 13.8, 2.1 Hz, 1 H), 1.27 (d, J = 7.1 Hz, 3H), 1.26 (d, J = 7.0 Hz, 3H). 13C NMR (DMSO-d6): δ 174.38, 156.1 1 , 150.82, 139.48, 1 16.39, 1 13.52, 75.92, 67.31 , 61 .80, 51 .36, 44.22, 29.29, 15.76, 15.36.

Exa

The transformation of 6 to dolutegravir with sodium hydroxide in ethanol was monitored for the interconversion of intermediates. The suspension of 6 (0.44 g) and solid sodium hydroxide (0.20 g) in ethanol (3.33 ml.) was stirred at 22 °C. Samples of the reaction mixture were taken after 3, 8 and 24 h for UPLC analysis. After 24 h, the reaction mixture was quenched with 2 M H2S04 (5 ml_), and left stirring at room temperature. The reaction mixture was filtered through fritted funnel, the product rinsed with water (30 ml.) and dried in vacuo at 50 °C overnight to afford dolutegravir as a white solid (0.27 g, 64 %).

The results of reaction monitoring:

Time UPLC analysis (area%)

Entry

(h) compound 6 compound 29 dolutegravir

1 3 h 37.50 20.63 39.99

2 8 h 0.78 15.46 80.32

3 24h 0.31 8.56 88.21

Example 29:

The effect of added water and reaction temperature was evaluated by monitoring 4 reactions in parallel. To the suspensions of 27 (0.86 g) in MeOH were added solid sodium hydroxide (0.40 g) or aqueous solution of NaOH (5 M, 2 ml.) (see Table below). The reactions were stirred in parallel at 50 °C or 22 °C. Samples were taken in timely intervals for UPLC analysis.

The results of reaction monitoring demethylation of 27 in MeOH:

Example 30:

The effect of added water and reaction temperature was evaluated by monitoring 4 reactions in parallel. To the suspensions of 6 (0.88 g) in EtOH were added solid sodium hydroxide (0.40 g) or aqueous solution of NaOH (5 M, 2 mL) (see Table below). The reactions were stirred in parallel at 50 °C or 22 °C. Samples were taken in timely intervals for UPLC analysis.

The results of reaction monitoring of the transformations of 6 in ethanol with NaOH:

dol. = dolutegravir

Exa

The effect of added water and reaction temperature was evaluated by monitoring 4 reactions in parallel. To the suspensions of 27 (0.88 g) in EtOH were added solid sodium hydroxide (0.40 g) or aqueous solution of NaOH (5 M, 2ml_) (see Table below). The reactions were stirred in parallel at 50 °C or 22 °C. Samples were taken in timely intervals for UPLC analysis.

The results of reaction monitoring of the transformations of 27 in ethanol with NaOH:

dol. = dolutegravir

Example 32:

Compound 3 (30 g, 1 10 mmol; assay 99%) was suspended in acetonitrile (450 mL), acetic acid (73 mL) and methanesulfonic acid (25 mL) were added. The reaction mixture was stirred 4 h at 70 °C. The clear red solution was cooled to 25 °C. Triethylamine (77 mL) and (S)-2-aminopropanol (17 mL) were added and the mixture was stirred at reflux temperature for 20 h. The reaction mixture was cooled to 25 °C and the insoluble product filtered, washed with 1 M HCI(aq) (60 mL), water (3 * 60 mL) and dried to give 4c (19.49 g, 67%): mp = 313-315 °C; 1H NMR (DMSO-d6): δ 1.31 (d, J = 6.3 Hz, 3H), 3.65 (dd, J = 8.6, 6.8 Hz, 1 H), 4.13 (dd, J = 1 1.7, 10.3 Hz, 1 H), 4.28 (m, 1 H), 4.39 (dd, J = 8.6, 6.8 Hz, 1 H), 4.92 (dd, J = 12.3, 4.2 Hz, 1 H), 5.45 (dd, J = 10.2, 4.1 Hz, 1 H), 7.16 (s, 1 H), 8.84 (s, 1 H), 15.74 (s, 1 H); 13C NMR (DMSO-d6) 16.5, 51.6, 52.9, 72.4, 81.6, 1 15.8, 1 18.1 , 141.5, 147.6, 153.4, 165.3, 179.0.

Example 33

Compound 4c (2.78 g) was suspended in dimethylformamide (40 mL), cooled to 0 °C, then triethylamine (3.52 mL) was added, followed by ethyl chloroformate (1 .31 mL). After 10 min there was added 2,4-difluorobenzylamine (1 .57 mL). The mixture was then stirred at 25 °C for 1 h. Water (150 mL) was added and the mixture extracted with dichloromethane (50 mL). The organic phase was separated, washed with water (2 χ 50 mL), dried over sodium sulfate and evaporated under reduced pressure. The residue (4.31 g) was treated with boiling 2-propanol (40 mL), the suspension cooled, the product filtered and dried to give the product 5c as a white powder (2.70 g, 69%): 99.80 area% by HPLC at 258 nm; mp = 222-223 °C; MS (ESI) m/z = 390 [MH]+; 1H NMR (DMSO-d6): δ 1 .30 (d, J = 6.3 Hz, 3H), 3.63 (dd, J = 8.6, 6.8 Hz, 1 H), 4.02 (m, 1 H), 4.26 (m, 1 H), 4.37 (dd, J = 8.6, 6.8 Hz, 1 H), 4.53 (d, J = 6.0 Hz, 2H), 4.84 (dd, J = 12.2, 4.2 Hz, 1 H), 5.40 (dd, J = 12.2, 4.2 Hz, 1 H), 6.91 (s, 1 H), 7.05 (m, 1 H), 7.24 (m, 1 H), 7.38 (m, 1 H), 8.62 (s, 1 H), 10.43 (t, J = 6.0 Hz, 1 H).

To a suspension of 5c (2.70 g, 6.9 mmol) in acetonitrile (32 mL) was added DABCO (39 mg, 5 mol%) and TCCA (1.01 g, 4.3 mmol). The mixture was stirred 20 h at 40 °C protected from light and then quenched with a mixture of DMSO (0.81 mL) and water (0.20 mL). The insoluble cyanuric acid was removed by filtration and washed with acetonitrile (10 mL). The filtrate was evaporated under reduced pressure to give viscous oil that was crystallized from a mixture of methanol (10 mL) and water (5 mL), by slowly cooling the solution from 60 °C to room temperature. The product 6c was filtered, washed with cold methanol (8 mL) and dried to give an off-white powder (1 .20 g, 41 %): mp = 225-227 °C; MS (ESI) m/z = 424 [MH]+; 1H NMR

(DMSO-d6): δ 1.28 (d, J = 6.3 Hz, 3H), 3.65 (dd, J = 8.6, 6.9 Hz, 1 H), 4.09 (m, 1 H), 4.26 (m, 1 H), 4.35 (dd, J = 8.6, 6.6 Hz, 1 H), 4.54 (d, J = 5.9 Hz, 2H), 4.85 (dd, J = 12.3, 3.8 Hz, 1 H), 5.42 (dd, J = 10.1 , 3.8 Hz, 1 H), 7.06 (m, 1 H), 7.24 (m, 1 H), 7.40 (m, 1 H), 8.67 (s, 1 H), 10.24 (t, J = 6.0 Hz, 1 H).

Example 35

cabotegravir

The suspension of 6c (1.00 g, 2.4 mmol) and sodium hydroxide (0.57 g, 14.2 mmol) in absolute ethanol (7 mL) was stirred at 40 °C for 16 h. The reaction was quenched with 0.5M H2S04 (15 mL), extracted with dichloromethane (20 mL), the extract washed with water (20 mL) and evaporated under reduced pressure. The residue was triturated in MTBE (10 mL), the product filtered, washed with MTBE (10 mL) and dried to give cabotegravir as an off-white solid (0.74 g, 77%): MS (ESI) m/z = 405 [MH]+.

Lek, a Sandoz company, opens the first production facility in Slovenia for drug substances for innovative medicines at its Mengeš site

Vojmir Urlep, president of Lek Board of Management

Dr Miro Cerar, the Prime Minister of the Republic of SloveniaPhoto for print

Dr Miro Cerar, the Prime Minister of the Republic of Slovenia

Lek, a Sandoz company, awarded for cooperation in practical training of students of the Faculty of Chemistry and Chemical Technology

30. 1. 2015

At a ceremony held on 22 January 2015 at the Faculty of Chemistry and Chemical Technology, University of Ljubljana, the Maks Samec awards and recognitions for 2014 were presented for the best doctoral thesis in the field of chemistry, the best doctoral thesis in the field of chemical engineering and chemical technology and for services and merits to the Faculty in the year 2014. On this occasion, the Faculty also wanted to thank all the companies and individuals who shared their knowledge and resources to help the Faculty on its education and research path.

Lek, a Sandoz company, received a plaque for taking part in the implementation of practical training, which was collected, on behalf of the company, by Samo Roš, Head of Human Resources and a Member of the Lek Board of Management. By doing so, the Faculty of Chemistry and Chemical Technology thanked all the mentors who directly transfer their expertise and valuable experience onto students, teaching them specific skills, encouraging their development, guiding them through the work process and ensuring that students become socialized in the workplace.

* * *

Lek, a Sandoz company, is one of key pillars of the second-largest generic pharmaceutical company globally. Its role within Sandoz is to act as: a leading global development center for technologically demanding products and technologies; a global manufacturing center for active pharmaceutical ingredients and medicines; a competence center for the development of vertically integrated products; a Sandoz competence center in the field of development and manufacturing of biosimilar products; and, a supply center for the markets of Central and Eastern Europe (CEE), South East Europe (SEE) and Commonwealth of Independent States (CIS), and it is responsible for sales on the Slovenian market. For further information please visit http://www.lek.si/en.

Sandoz, the generic pharmaceuticals division of Novartis, is a global leader in the generic pharmaceutical sector. Sandoz employs over 26,400 employees and its products are available in more than 160 countries, offering a broad range of high-quality, affordable products that are no longer protected by patents. With USD 9.6 billion in sales in 2014, Sandoz has a portfolio of approximately 1,100 molecules, and holds the #1 position globally in biosimilars as well as in generic injectables, ophthalmics, dermatology and antibiotics, complemented by leading positions in the cardiovascular, metabolism, central nervous system, pain, gastrointestinal, respiratory, and hormonal therapeutic areas. Sandoz develops, produces, and markets these medicines, as well as active pharmaceutical and biotechnological substances. Nearly half of Sandoz’s portfolio is in differentiated products, which are defined as products that are more difficult to scientifically develop and manufacture than standard generics. In addition to strong organic growth since consolidating its generics businesses under the Sandoz brand name in 2003, Sandoz has benefitted from strong growth of its acquisitions, which include Lek (Slovenia), Sabex (Canada), Hexal (Germany), Eon Labs (US), EBEWE Pharma (Austria), Oriel Therapeutics (US), and Fougera Pharmaceuticals (US).
Sandoz is on Twitter. Sign up to follow @Sandoz_global at http://twitter.com/Sandoz_Global.

Novartis provides innovative healthcare solutions that address the evolving needs of patients and societies. Headquartered in Basel, Switzerland, Novartis offers a diversified portfolio to best meet these needs: innovative medicines, eye care, cost-saving generic pharmaceuticals, preventive vaccines and over-the-counter products. Novartis is the only global company with leading positions in these areas. In 2014, the Group achieved net sales of USD 58.0 billion, while R&D throughout the Group amounted to approximately USD 9.9 billion (USD 9.6 billion excluding impairment and amortization charges). Novartis Group companies employ approximately 130,000 full-time-equivalent associates. Novartis products are available in more than 180 countries around the world. For more information, please visit www.novartis.com

////////////Carbotegravir, Dolutegravir, New Patent, WO 2016113372, Lek Pharmaceutical and Chemical Co DD

New Patent, WO 2016110874, Artemisinin , IPCA Laboratories Ltd


 

 

New Patent, WO 2016110874, Artemisinin , IPCA Laboratories Ltd

FOR Cancer; Parasitic infection; Plasmodium falciparum infection; Viral infection

WO-2016110874

KUMAR, Ashok; (IN).
SINGH, Dharmendra; (IN).
MAURYA, Ghanshyam; (IN).
WAKCHAURE, Yogesh; (IN)

Dr. Ashok Kumar, President – Research and Development (Chemical) at IPCA LABORATORIES LTD

IPCA LABORATORIES LIMITED [IN/IN]; 48, Kandivli Industrial Estate, Charkop, Kandivali (West), Mumbai 400067 (IN)

Novel process for preparing artemisinin or its derivatives such as dihydroartemisinin, artemether, arteether and artesunate. Also claims novel intermediates of artemesinin such as artemisinic acid or dihydroartemisinic acid. Discloses the use of artemisinin or its derivatives, for treating malaria, cancer, viral and parasitic infections.

In July 2016, Newport Premium™ reported that IPCA was capable of producing commercial quantities of artemether, arteether and artesunate; and holds an inactive US DMF for artemether since February 2009. In July 2016, IPCA’s website lists artemether, arteether and artesunate under its products and also lists artemether and artesunate as having EDMF and WHO certificates. The assignee also has Canada HPFB certificate for artemether.

The Central Drug Research Institute (CDRI) in collaboration with IPCA is developing CDRI-97/78 (1,2,4 trioxane derivative), a synthetic artemisinin substitute for treating drug resistant Plasmodium falciparum infection. In July 2016, CDRI-97/78 was reported to be in phase 1 clinical development. IPCA in collaboration with CDRI was also investigating CDRI-99/411, a synthetic artemisinin substitute for treating malaria; but its development had been presumed to have been discontinued; however, this application’s publication would suggest otherwise.

Writeup

Artemisinin is an active phytoconstituent of Chinese medicinal herb Artemisia annua, useful for the treatment of malaria. Generally, artemisinin/artemisinic acid is obtained by extraction of the plant, Artemisia annua. The plant Artemisia annua was first mentioned in an ancient Chinese medicine book written on silk in the West Han Dynasty at around 200 B.C. The plant’s anti-malarial application was first described in a Chinese pharmacopeia, titled “Chinese Handbook of Prescriptions for Emergency Treatments,” written at around 340 A.D.

Artemisinin being poorly bioavailable limits its effectiveness. Therefore semisynthetic derivatives of artemisinin such as artesunate, dihydroartemisinin, artelinate, artemether, arteether have been developed to improve the bioavailability of Artemisinin.

Artemisinin and its derivatives – dihydroartemisinin, artemether, arteether, and artesunate being a class of antimalarials compounds used for the treatment of uncomplicated, severe complicated/cerebral and multi drug resistant malaria. Additionally, there are research findings that artemisinin and its derivatives show anti-parasite, anti-cancer, and anti-viral activities.

Dihydroartemisinin Artesunate

The content of Artemisinin in the plant Artemisia annua varies significantly according to the climate and region/geographical area where it is cultivated. Further, the extraction methods provide artemisinin or artemisinic acid from the plant in very poor yields and therefore not sufficient to accommodate the ever-growing need for this important drug. Consequently, widespread use of these valuable drugs has been hampered due to the low availability of this natural product. Therefore, research has focused on the syntheses of this valuable drug in a larger scale to meet the increasing global demand and accordingly ample literature is available on the synthesis of artemisinin or its derivatives, but no commercial success being reported / known till date.

Artemisinin can be prepared synthetically from its precursors such as artemisinic acid or dihydroartemisinic acid according to literature methods known to skilled artisans. For example, dihydroartemisinic acid can be converted to artemisinin by a combination of photooxidation and air-oxidation processes as described in U.S. Patent No. 4,992,561.

Amorphadiene is an early starting material for synthesis of Artemisinic acid or dihydroartemisinic acid, which is an important intermediate for producing Artemisinin commercially, and WO2006128126 reported a preparation method as mentioned in scheme- 1.


acid

In accordance with the scheme 1, the amorphadiene is treated with di(cyclohexyl)borane ( δΗι ΒΗ followed by reaction with H2O2 in presence of NaOH to obtain the amorph-4-ene 12-ol which is further oxidized to dihydroartemisinic acid using CrCb/ifcSC^. The formation of amorph-4-ene 12-ol is taking place via epoxidation of the exocyclic double bond. However, the reported yields of this synthesis are very low, making it unviable to produce artemisinic acid at a cheaper cost than natural extraction, for commercial use.

Amorpha -4, 11-diene

A similar method is published in, WO2009088404, for synthesis of dihydroartemisinic acid through preparation of amorph-4-ene-12-ol via epoxide formation, albeit, predominantly at exo position by reacting the amorpha-4,11-diene with H2O2 in presence of porphyrin catalyst (TDCPPMnCl). During reaction, epoxidation also occurred at endo position leading to formation of Amorphadiene- 4,5- epoxide that remain as impurity. The formed exo epoxide (amorphadiene – 11, 12 – epoxide) is further reduced to get amorph- 4-ene 12-ol and then converted to dihydroartemisinic acid and finally converted into artemisinin.

Amorphadiene-11,12-epoxide

This process involves expensive & industry unfriendly reagents. Moreover, desired stereo isomers were obtained only in poor yields, because several purification steps were needed to get desired stereo isomers leading to escalated production/operational costs.

Therefore there remains a need in the art to improve the yield of Dihydroartemisinic acid, which could potentially reduce the cost of production of Artemisinin and/or its derivatives. Consequently it is the need of the hour to provide a synthetic and economically viable process to meet the growing worldwide demand by improving the process for Artemisinin and/or its derivatives to obtain them in substantially higher yields with good purity by plant friendly operations like crystallization/extractions rather than column chromatography/other cost constraint procedures.

Therefore, the object of the invention is to prepare Artemisinic acid of formula-II, Dihydroartemisinic acid of formula-IIa, Artemisinin and its derivatives through Amorphadiene- 4,5- epoxide.

DHAA methyl ester

Scheme 2

Method 4 (From compound of formula IV (R = CI)):

In the 4-neck round bottom flask was charged Diphenyl sulfoxide (23.8 g), NaHC03 (32.96 g) and DMSO (80 ml) at 30°C. Further a solution of compound of formula IV (R = CI) (10 g) in DMSO (20 ml) was charged to the reaction mass at 30°C followed by heating and maintaining the temperature for 40 hours at 80°C till completion. DMSO was distilled out under vacuum. The reaction mass was cooled followed by charging water

(100 ml) and toluene (100 ml) to the reaction mass with stirring for 30 minutes at 28°C. The layers were separated out and aqueous layer was back extracted with toluene (2 X 100 ml). The organic layer was washed with water (100 ml) and saturated brine solution (100 ml). Solvent was distilled out under vacuum at 50°C, and the crude mass degassed under vacuum at 50-55°C. IPA (40 ml) was charged to the mass. Simultaneous addition of hydrazine hydrate (65% in aqueous solution) (3.8 g) and hydrogen peroxide (50% in aqueous solution) (2.5 ml) was done at 30-32°C over a period of 3.25 hours. After completion, reaction mass was cooled up to 5-10°C and water (100ml) was added to the reaction mass. The pH of the reaction mass was adjusted to 3.8 with dilute 8% aqueous HC1 (24 ml) at 10°C. Ethyl acetate (60 ml) was added to the reaction mass at 10°C and stirred for 15 minutes at 15-20°C. The layers were separated. Aqueous layer was back extracted with ethyl acetate (2 X 20 ml). The combined organic layer was washed with 10%) sodium metabisulfite solution (50 ml), water (50 ml) and saturated brine solution (50 ml). The organic layer was distilled out under vacuum at 45°C and the obtained crude mass was degassed at 50-55°C. To this was added DME (40 ml), Biphenyl (0.9 g) and Li-metal (1.63 g) and the reaction mass was maintained for 10 hours at 80-85°C till reaction completion. The reaction mass was cooled up to 0-5°C followed by drop wise addition of water within one hour, and the reaction stirred for two hours at 20-25°C. Toluene (35 ml) was charged with stirring and layers were separated. The aqueous layer was washed with toluene (35 ml) and the combined toluene layer was washed with water (20 ml). The combined aqueous layer was again washed with toluene (20 ml). The aqueous layer was cooled to 10-15°C and pH adjusted to 3.5-4 with dilute 16% aqueous HC1. MDC (50 ml) was charged and stirred 30 minutes at 20-25°C followed by separation of layers. The aqueous layer extracted with MDC (25 ml) and the combined MDC layer was washed with water (50 ml), then with saturated NaCl solution (25 ml). The solvent was distilled out under vacuum at 40-45°C and the crude mass (Purity: 70-80%>) was degassed at 65-70°C. The crude product (10 g) was dissolved in ethyl acetate (200 ml). 10%> aqueous NaOH (100 ml) was charged to the reaction mass and stirred one hour at 20°C followed by layer separation. Again 10%> aqueous NaOH (100ml) was added to the organic layer, stirred for 30 minutes and layers were separated out. The pH of the combined NaOH solution wash was adjusted to 4.0 with dilute 16%> aqueous HC1 at 5-10°C under stirring. Ethyl acetate (850 ml) was charged to aqueous acidic mass, stirred 30 minutes and layers were separated out. The aqueous layer was back extracted with ethyl acetate (2 X 30 ml) and the combined organic layer was washed with water (100 ml) and saturated brine (50 ml). The organic layer was dried over sodium chloride, solvent was distilled out under vacuum and the purified mass was degassed under vacuum at 50-55°C to obtain Dihydroartemisinic acid (Purity: 90-95%).

b) Methyl ester of Dihydroartemisinic acid:

To a clear solution of Dihydroartemisinic acid (40 g) dissolved in MDC (120 ml) was added thionyl chloride (SOCh) (14.85 ml) at 10±2°C and reaction mass was heated to reflux temperature 40±2°C. After the completion of reaction, solvent was distilled out and excess SOCh was removed under reduced pressure. The resulting concentrated mass of acid chloride was dissolved in MDC (200 ml). In another RBF was taken triethylamine (30.6 ml) and methanol (120 ml). To this solution was added above acid chloride solution at 30±2°C and maintained till completion of reaction. To the reaction mass was added water (400 ml) and organic layer was separated. The aqueous layer was washed with MDC and mixed with main organic layer and the combined organic layer was back washed with water till neutral pH. Then organic layer was concentrated to give methyl ester of Dihydroartemisinic acid as a brown color oily mass.

Weight: 41.88 gm

Yield = 98%

c) Artemisinin:

Methyl ester of dihydroartemisinic acid (67.7 g) was dissolved in methanol (338 ml). To this solution was added Sodium molybdate (29.5 g), 50% hydrogen peroxide (147.3 g) was added at 30±2°C and reaction was maintained for 3-4 hours. After completion of reaction was added water (300 ml) and MDC (300 ml) to the reaction mass. The organic layer was separated and aqueous layer washed with MDC (100 ml). The combined organic layer was concentrated to 475 ml containing hydroperoxide intermediate and directly used for next stage reaction. In another RBF containing MDC (475 ml) was added benzene sulfonic acid (1.27 g) and Indion resin (6.7 g). This heterogeneous solution was saturated with oxygen by passing O2 gas for 10 min at 0±2°C. To this was added previous stage hydroperoxide solution at same temperature with continuous 02 gas purging within 30-40 minutes. The oxygen gas was passed at same temp for 4 hours and temperature raised to 15±2°C with continued passing of oxygen for 5 hours. The

mixture was stirred at 25-30°C for 8-10 hours followed by filtration of resin. The filtrate was washed with water (200 ml X 3) and the combined aqueous layer back washed with MDC (50 ml). The combined organic layer was concentrated to give crude Artemisinin. Weight: 54 gm

Yield= 70.7%

Purification of Artemisinin:

Crude Artemisinin (10 g) was dissolved in ethyl acetate (25 ml) at 45-50°C. The solution was cooled to 30-35°C followed by addition of n-Hexane (100 ml). The material was isolated, stirred for 2 hours, filtered and vacuum dried at 45°C.

Weight: 4 gm

Yield: 40%

THE VIEWS EXPRESSED ARE MY PERSONAL AND IN NO-WAY SUGGEST THE VIEWS OF THE PROFESSIONAL BODY OR THE COMPANY THAT I REPRESENT, amcrasto@gmail.com, +91 9323115463 India

////////New Patent, WO 2016110874, Artemisinin , IPCA Laboratories Ltd, malaria, Cancer,  Parasitic infection,  Plasmodium falciparum infection,  Viral infection, artemether artemisinin,  artemotil,  artenimol,  artesunate,

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