Nitrogen and sulfur containing heterocycles. 50. Synthesis and reactions of 6-oxopyrimido[4,5-b][1,4]thiazine-7-carboxylic acid derivatives

Reaction of 5-amino-6 mercaptopyrimidines with diethyl bromomalonate gave ethyl 6-oxopyrimido-4,5-b]1,4]thiazine-7-carboxylates, from which there was synthesized a series of derivatives at the carboxyl group (amides, hydrazides, and, from the latter, urethanes). Desulfurization of the 6-oxopyrimidothiazine-7-carboxylic acid esters gave N-(pyrimidin-5-yl)monoamides of ethyl malonate.For communication 49 see 1].Center for Chemistry of Drugs—All-Russian Research Chemical-Pharmaceutical Institute, Moscow 119021, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 822–828, June, 1999.