Pyrylium-mediated transformations of natural products. Part 7. Displacement of the N-substituents of pyridinium ions in aqueous solution: replacement of the ω-amino group of lysine, and of the terminal amino group of glycylglycine

Abstract

In two-step sequences, lysine has been converted into the thio-substituted derivatives RS[CH₂]₄CH(NH₂)CO₂H (R = Ph or PhCH₂), and glycylglycine into PhSCH₂CONHCH₂CO₂H. All reactions proceeded in aqueous solution at ⩽75 °C; they thus provide models for the selective conversion of proteins at the ω-amino groups of lysine side chains and at the terminal amino groups, respectively.