N-carboalkoxy-2-nitrobenzenesulfonamides: A practical preparation of N-Boc-, N-Alloc-, and N-Cbz-protected primary amines

N-Carboalkoxy-2-nitrobenzenesulfonamides readily prepared by acylation of 2 -nitrobenzenesulfonamide (o-NsNH(2)), can be alkylated by either convention al or Mitsunobu protocols. Since the o-nosyl group can be deprotected under mild conditions, a variety of N-carboalkoxy derivatives of primary amines may be prepared in excellent yields from the corresponding alcohols and/or halides. In addition, allyloxycarbonyl (Alloc), t-butoxycarbonyl (t-Boc), a nd benzyloxycarbonyl (Cbz) groups can be deprotected in the presence of the o-nosyl group, allowing the resultant N-alkylated 2-nitrobenzenesulfonamid es to be used for further preparation of secondary amines.