The present invention relates to methods for the preparation of benzoxazole sulfonamide compounds of formula (9) as well as novel intermediates of formula (6) for use in said method. More in particular the invention relates to methods for the Preparation of 2-amino-benzoxazole sulfonamide compounds which make use of 2-mercapto-benzoxazole sulfonamide intermediates, more in particular methods employing the intermediate 1-Benzy1-2-hydroxy-3-[isobutyl­(2-methylsulfanyl-benzoxazole-6-sulfonyl)-amino)-propyl)-carbamic ester, and to methods amenable to industrial scaling up. Said benzoxazole sulfonamide compounds are particularly useful as HIV protease inhibitors. The substituents are defined in the claims.