The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 23, 2011
Filed:
Mar. 19, 2007
Srinivas Laxminarayan Pathi, Bangalore, IN;
Rajendra Narayanrao Kankan, Mumbai, IN;
Dharmaraj Ramachandra Rao, Mumbai, IN;
Sandip Vasant Chikhalikar, Mumbai, IN;
Srinivas Laxminarayan Pathi, Bangalore, IN;
Rajendra Narayanrao Kankan, Mumbai, IN;
Dharmaraj Ramachandra Rao, Mumbai, IN;
Sandip Vasant Chikhalikar, Mumbai, IN;
CIPLA Limited, Mumbai, IN;
Abstract
The present invention relates to a process for the preparation of 4-[1-(4-cyano phenyl)-1-(1,2,4-triazol-1-yl)methyl]benzonitrile (letrozole), substantially free from its isomeric impurity. The preparation involves reaction of 4-[1-(1H-1,2,4-triazol-1-yl)methylene benzonitrile with 4-fluorobenzonitrile in the presence of an organic solvent and a silicon amine. The present invention also relates to a process for the preparation of 4-[1-(1H-1,2,4-triazol-1-yl)methylene benzonitrile which involves: (a) the reaction of a 4-halomethyl benzonitrile with 1,2,4-triazole in the presence of cesium carbonate and an organic solvent to obtain a reaction mass comprising 4-[1-(1,2,4-triazole-1-yl)methyl]benzonitrile of formula II; and (b) precipitation of 4-[1-(1,2,4-triazole-1-yl)methyl]benzonitrile (II) from the reaction mass using a suitable organic solvent.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile