Synthesis of ureidopeptides using pentafluorophenyl carbamates from N a-Fmoc-peptide acids

Highly active and shelf stable pentafluoro phenol derived Fmoc-peptidyl carbamates have been synthesized from corresponding Fmoc-peptidyl isocyanates. The utility of pentafluorophenyl carbamate intermediates has been demonstrated by the synthesis of tri, penta and hexapeptidyl ureas which are obtained in good yields. All the synthesised compounds have been characterized by 1H NMR, 13C NMR and mass spectroscopy. The coupling reaction using pentafluorophenyl carbamates to insert urea bond between α amino acids is fast, clean and high yielding