α-Imino acids, prepared from α-ketoacids and primary amines, undergo facile decarboxylation to the corresponding imines on heating at ⩽,80°C in benzene or methylene chloride. Decarboxylation proceeds via a 1,2-ylide which can be trapped by sulphur to give the corresponding secondary thioamides in good yield. 1,2-Ylides from secondary amines and ∞-keto acids can be generated in situ and trapped with
Ready decarboxylation of imines of α-keto acids. Mechanism and application to thioamide synthesis
作者:Moustafa F. Aly、Ronald Grigg
DOI:10.1039/c39850001523
日期:——
α-Keto a ids are readily decarboxylated via imine formation with primary and/or secondary amines even when imine–enamine isomerisation can occur; the process is thoyghy to involve an intermediate zwitteriion which can be trapped by sulphur to give thiamides in excellent yield.