The invention relates to a process for the preparation of Atazanavir, which comprises reacting the hydrochloride salt of compound (6) with N-methoxycarbonyl-L-tert-leucine, the removal of the benzyloxycarbonyl group and the reaction with methoxycarbonyl chloride. The process is particularly advantageous in that it allows to use reduced amounts of N-methoxycarbonyl-L-tert-leucine and avoids the use of unstable intermediates.
