PROCESS FOR THE PREPARATION OF ATAZANAVIR SULFATE SUBSTANTIALLY FREE OF DIASTEREOMERS

摘要

The present invention provides atazanavir sulfate substantially free of diastereomeric impurities. The present invention also provides atazanavir sulfate having D-tertiary leucine analogues less than 0.1%. The present invention further relates to an improved process for preparing atazanavir sulfate, substantially free of its diastereoisomeric impurities, which comprises of reacting diamino compound (IV) with N-methoxycarbonyl-(L)-tertiary-leucine (V) having D-isomer less than 0.1 % to obtain atazanavir base; conversion of atazanavir base to atazanavir sulfate by reacting with sulfuric acid and crystallization of atazanavir sulfate from suitable organic solvent(s).