Provided is a method for preparing letrozole, which includes reacting an activated bis-(4-cyanophenyl)-methane with a triazole to produce letrozole, and, optionally, purifying the letrozole. Also provided are highly pure letrozole, and a method of purifying letrozole, which method includes precipitating letrozole, e.g., by selective precipitation from a reaction mixture and/or by subjecting the letrozole to one or more crystallizations.
[EN] REGIOSELECTIVE SYNTHESIS OF LETROZOLE<br/>[FR] SYNTHÈSE RÉGIOSÉLECTIVE DE LÉTROZOLE
申请人:GENERICS UK LTD
公开号:WO2010146391A1
公开(公告)日:2010-12-23
The present invention relates to an improved process for the preparation of letrozole (I) and its pharmaceutically acceptable salts, to compositions comprising letrozole or a pharmaceutically acceptable salt thereof, and to uses of such compositions. In particular it relates to a process and to novel intermediates for preparing letrozole and its salts substantially free from regioisomeric impurities.
The present invention relates to the process for the preparation of Letrozole free from its regioisomer (7) and other impurities by selective extraction of desired intermediate (3) using suitable solvent and mixture of solvents.
[EN] AN IMPROVED PROCESS FOR PREPARATION OF LETROZOLE AND ITS INTERMEDIATES<br/>[FR] PROCÉDÉ PERFECTIONNÉ DE PRÉPARATION DU LÉTROZOLE ET SES INTERMÉDIAIRES
申请人:DABUR PHARMA LTD
公开号:WO2009069140A1
公开(公告)日:2009-06-04
The present invention relates to an improved process for preparation of the non-steroidal aromatase inhibitor drug, Letrozole of formula (I) and its intermediates, 4-[1-(1,2,4-triazolyl) methyl]-benzonitrile of formula (IV) and 4-[1-(1,2,4-triazolyl) methyl]-benzonitrile hydrochloride of formula (VII), all having a purity of ≥99%, which is simple, convenient, economical, does not use hazardous chemicals and industrially viable.