WO 2015104605.new patent on Rivaroxaban, Wockhardt Ltd

Process for preparing rivaroxaban - comprising the reaction of a thioester compound and its salts with 4-{4-[(5S)-5-(aminomethyl)-2-oxo-1,3-oxazolidin-3-yl]phenyl}morpholine-3-one.

WO-2015104605

SHUKLA, Jagdish Dattopant; (IN).
YADAV, Ramprasad; (IN).
MERWADE, Arvind Yekanathsa; (IN).
DEO, Keshav; (IN)

Wockhardt Ltd

The synthesis of (II) via intermediate (I) is described (example 7, page 15)

4-{4-[(5S)-5-(Aminomethyl)-2-oxo-1,3-oxazolidin-3-yl]phenyl}morpholine-3-one (formula III) is (I) and rivaroxaban is (II) (claim 1, page 16).

The present invention relates to a process for the preparation of Rivaroxaban and its novel intermediates, or pharmaceutically acceptable salts thereof. The present invention provides novel intermediates, which may be useful for the preparation of Rivaroxaban or its pharmaceutically acceptable salts thereof. The process of preparation by using novel intermediate is very simple cost effective and may be employed at commercial scale. The product obtained by using novel intermediate yield the Rivaroxaban of purity 99% or more, when measured by HPLC. The present invention especially relates to a process for the preparation of Rivaroxaban from thioester of formula II, or a pharmaceutically acceptable salt thereof, wherein R is leaving group.

A PROCESS FOR PREPARING RIVAROXABAN OR A PHARMACEUTICALLY ACCEPTABLE SALT THEREOF Field of Invention The present invention relates to a process for the preparation of Rivaroxaban and its novel intermediates, or pharmaceutically acceptable salts thereof. The present invention provides novel intermediates, which may be useful for the preparation of Rivaroxaban or its pharmaceutically acceptable salts thereof. The process of preparation by using novel intermediate is very simple cost effective and may be employed at commercial scale. The product obtained by using novel intermediate yield the Rivaroxaban of purity 99% or more, when measured by HPLC. The novel thioester intermediate represented by formula II Formula II or a pharmaceutically acceptable salt thereof, wherein R is leaving group. Background of the invention The drug compound having the adopted name "Rivaroxaban" has chemical name, 5-chloro-N-({(5S)-2-oxo-3-[4-(3-oxo-4-morpholinyl)phenyl]-l,3-oxazolidin-5- yljmethyl)-2-thiophenecarboxamide; and has the structural formula I, Formula I The commercial pharmaceutical product XARELTO® tablets, contains rivaroxaban as active ingredient. Rivaroxaban is a factor Xa inhibitor useful as oral anticoagulant. Rivaroxaban can be used for the prevention and treatment of various thromboembolic diseases, in particular of deep vein thrombosis (DVT), pulmonary embolism (PE), myocardial infract, angina pectoris and restenoses after angioplasty or aortocoronary bypass, cerebral stroke, transitory ischemic attacks, and peripheral arterial occlusive diseases. U.S. Patent No. 7, 157,456 describes Rivaroxaban and process for the preparation thereof. The process of US '456 for rivaroxaban involves reaction of 2-[(2S)-2-oxiranylmethyl]-lH-isoindole-l,3(2H)-dione with 4-(4-aminophenyl)-3-morpholinone to provide 2-((2R)-2-hydroxy-3- { [4-(3-oxo-4-morpholiny)phenyl]amino Jpropyl)- lH-isoindole- 1 ,3(2H)-dione, which on cyclization using Ν,Ν-carbonyl diimidazole to afford 2-({5S)-2-Oxo-3-[4-(3-oxo-4-morpholiny)phenyl]-l,3-oxazolidin-5-yl}methyl)-lH-isoindole-l,3(2H)-dione, which on reacted with methylamine followed by reaction with 5-chlorothiophene-2-carbonyl chloride to provide Rivaroxaban. Various processes for the preparation of rivaroxaban, its intermediates, and related compounds are disclosed in U.S. Patent Nos. 7,585,860; 7,351,823, 7,816,355, and 8,101,609; patent application Nos. WO 2011/012321, WO 2012/156983, WO 2012/153155, WO 2013/053739, WO 2013/098833, WO 2013/156936, WO 2013/152168, WO 2013/120464, WO 2013/164833, US 2012/0283434 and US 2013/184457; and J. Med. Chem. 2005, 48, 5900-5908. The reported processes suffers one or the other problems like lower yield, use of carcinogenic reagents like hydrobromic acid at elevated temperature, longer reaction time, and the like. Therefore, there is a need to develop a simple and industrially feasible process for Rivaroxaban and its intermediates or a pharmaceutically acceptable salt thereof.

Wockhardt Ltd chairman Habil Khorakiwala

process includes the step of , reacting thioester of formula IIA or pharmaceutically acceptable salt thereof

Formula IIA

with 4-{4-[(5S)-5-(aminomethyl)-2-oxo-l,3-oxazolidin-3-yl]phenyl}morpholine-3-one of formula III,

Formula III

Formula I

EXAMPLE 7: One pot process for Rivaroxaban

The triphenylphosphine (11.5g) and mercaptobenzothiazole disulphide (15.31g) were taken in methylene chloride and reaction mixture was stirred at 28°C -30°C for 1 hr. The 5-chlorothiophene-2-carboxylic acid (7.2g) and triethylamine (3.8 g) were added to the above reaction mixture. The reaction mixture is stirred at 0°C -25 °C for 1 hr. after 1 hr 4-{4-[(5S)-5-(aminomethyl)-2-oxo-l,3-oxazolidin-3-yl]phenyl}morpholine-3-one (lOg) and triethylamine (3.8g) were added. The resulting reaction mixture further stirred for 2 hrs. After completion of the reaction, water was added and stirred for 10 min. aqueous layer was separated and washed with methylene chloride. The organic layer was acidified to pH 6-7 with 2N hydrochloric acid and finally the organic layer was concentrated to get desired product. The product was purified and dried to yield Rivaroxaban.

Yield: 10.0 gm

Purity: 99.3 %

EXAMPLE 8: One pot process for Rivaroxaban

Exemplified procedure in example 7 with the replacement of solvent ethyl acetate and base potassium hydroxide were used to get the rivaroxaban.

EXAMPLE 9: One pot process for Rivaroxaban

Exemplified procedure in example 7 with the replacement of solvent acetonitile and base potassium carbonate were used, methylene chloride was added in the reaction mixture to extract the Rivaroxaban.

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