New method of preparation of finasteride.

摘要

Disclosed is a new process for producing finasteride which involves reacting the magnesium halide salt of 17 beta -carboalkoxy-4-aza-5 alpha -androst-1-en-3-one with t-butylamino magnesium halide, present in at least a 2:1 molar ratio to the ester, formed from t-butyl amine and an aliphatic/aryl magnesium halide at ambient temperature in an inert organic solvent under an inert atmosphere followed by heating and recovering the product finasteride. Also disclosed are two polymorphic crystalline Forms I and II of finasteride, and methods of their production.