N-quaternary compounds. Part XXIX. Selective removal of the N-chloroacetyl group in peptides

Abstract

The N-chloroacetyl group can be removed from amino-acids and dipeptides in two steps as follows. The chloroacetamide and a pyridine-2-thione are initially condensed in aqueous sodium hydrogen carbonate. The condensation product in cold trifluoroacetic acid undergoes cyclisation with concomitant liberation of the amine. Effects of substituents in the pyridine system and in the amine have been studied. The best reagent was found to be 3-nitropyridine-2-thione.