FMOC-and NSC-groups As a Base Labile N(a)-Amino Protection: a Comparative Study in the Automated SPPS

Base-labile 2-(4-nitrophenylsulfonyl)ethoxycarbonyl (Nsc) and 9-fluorenylmethoxycarbonyl (Fmoc) groups are compared as a temporary N(alpha)-amino protection in the automated SPPS of IFN-alpha(2)(130-137), ACP(65-74) and ACTH(1-24) on MilliGen 9050+ PepSynthesizer(TM). The syntheses were performed on PEG-PS and Wang PS resins using standard BOP/DIEA protocol with some modifications. HPLC profiles of the crude peptides and isolated yields resulted from both Nsc and Fmoc assemblies were almost identical for the three test peptides.