FIELD: chemical industry. SUBSTANCE: present invention describes novel method of preparing finasteride, 17β-[N- tert-butylcarbamoyl] -4-aza-5α-androst-1-en-3-one (2) which comprises reacting ester I, 17β-carboalkoxy-4-aza- 5α-androst-1-en-3-one with t-butylamine magnesium halide present in molar ratio to ester of least 2:1. Product is formed from t-butyl amine and aliphatic aryl magnesium halide at ambient temperature in inert organic solvent in inert gas atmosphere and finasteride product is then heater and recovered. Present invention also describes two polymorphous crystalline forms I and II of finasteride and methods of preparation thereof. Finasteride is 5α-reductase inhibitor. EFFECT: more efficient preparation method. 36 cl, 4 ex
Authors
Dates
1998-10-20—Published
1993-11-05—Filed