Pyruvoyl, a novel amino protecting group on the solid phase peptide synthesis and the peptide condensation reaction

In one of the peptide condensation methods termed thioester method, an amino protecting group is required in the lysine side chain. In this study, to investigate the efficiency of the pyruvoyl group as an amino protecting group, we synthesized N^α-fluorenylmethoxycarbonyl (Fmoc)-N^ε-pyruvoyl-lysine and introduced it into peptides and glycopeptides by the ordinary Fmoc-based solid phase peptide synthesis. The pyruvoyl peptide could be condensed with a peptide thioester by the thioester method, and this protecting group was easily removed by o-phenylenediamine treatment without significant side reactions.