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.