C - Chemistry – Metallurgy – 07 – D
Patent
C - Chemistry, Metallurgy
07
D
C07D 249/08 (2006.01)
Patent
CA 2645893
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-(1 H-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-(1 H- 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.
La présente invention concerne un procédé de synthèse du 4-[1-(4-cyanophényl)-1-(1,2,4-triazol-1-yl)méthyl]benzonitrile (létrozole) ne contenant sensiblement aucune impureté isomère. La préparation implique la réaction du 4-[1-(1H-1,2,4-triazol-1-yl)méthylènebenzonitrile avec le 4-fluorobenzonitrile en présence d'un solvant organique et d'une silylamine. La présente invention concerne également un procédé de synthèse du 4-[1-(1H-1,2,4-triazol-1-yl)méthylènebenzonitrile qui implique : (a) la réaction d'un 4-halogénométhylbenzonitrile avec le 1,2,4-triazole en présence de carbonate de césium et d'un solvant organique pour obtenir un mélange réactionnel comprenant le 4-[1-(1,2,4-triazol-1-yl)méthyl]benzonitrile de formule II ; et (b) la précipitation du 4-[1-(1,2,4-triazol-1-yl)méthyl]benzonitrile (II) depuis le mélange réactionnel en utilisant un solvant organique adapté.
Chikhalikar Sandip Vasant
Kankan Rajendra Narayanrao
Pathi Srinivas Laxminarayan
Rao Dharmaraj Ramachanadra
Cipla Limited
Sim & Mcburney
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