METHOD FOR PREPARING FINASTERIDE

摘要

PURPOSE: Provided is a novel method for preparing a finasteride by using economical and environmentally safe reagents under a relatively mild condition with a high efficiency. CONSTITUTION: The method for preparing the finasteride of the formula 1 is characterized by comprising the steps of: reacting N-(1,1-dimethylethyl)-3-oxo-4-aza-5 alpha-androstan-17-beta-carboxamide of the formula 2 with an organophosphorus and a halogen in the presence of an amine and a basic alumina to form the alpha-halogenated compound of the formula 6; and performing the dehalogenation of the compound of the formula 6 to form the finasteride of the formula 1.