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:
Apr. 27, 2010
Filed:
Jul. 06, 2006
Peter Lindsay Macdonald, Gentilino, CH;
Ettore Bigatti, Balerna, CH;
Pierluigi Rossetto, Balerna, CH;
Zvi Harel, Kfar Saba, IL;
Peter Lindsay MacDonald, Gentilino, CH;
Ettore Bigatti, Balerna, CH;
Pierluigi Rossetto, Balerna, CH;
Zvi Harel, Kfar Saba, IL;
Sicor, Inc., Irvine, CA (US);
Abstract
The invention provides a high-yield process for the preparation of letrozole having a high purity, without the need for removal of the 4-[1-(1,3,4-triazolyl)methyl]benzonitrile impurity at the intermediate stage. The invention also provides a process for the synthesis of letrozole in which formation of the impurity 4-[1-(1,3,4-triazolyl)methyl]benzonitrile during the first stage is minimized. In the process, a 4-(halomethyl)benzonitrile is reacted with a salt of 1H-1,2,4-triazole, reducing the formation of the impurity. Preferably, the preparation is conducted as a one-pot process.