Safety-catch anchoring linkage for synthesis of peptide amides by Boc/Fmoc strategy

Abstract

2-Methoxy-4,4'-bis(methylthio)benzhydrylamine ( 10) and the corresponding disulfoxide were prepared and tested as a model amide protecting groups for their stability toward acidic conditions. Subsequently, the novel 4-[4,4'-bis(methylsulfinyl)-2-oxy-(9-fluorenylmethyloxycarbonyl) berzhydrylamino]butanoic acid (SCAL) handle ( 9) has been prepared and applied to solid-phase peptide synthesis of C-terminal peptide amide using both 9-fluorenylmethyloxycarbonyl (Fmoc) and tert-butyloxycarbonyl (Boc) groups for N α-amino protection.