ChemInform Abstract: Nitrogen and Sulfur Containing Heterocycles. Part 50. Synthesis and Reactions of 6‐Oxopyrimido[4,5‐b][1,4]thiazine‐7‐carboxylic Acid Derivatives.

Abstract

Nitrogen and Sulfur Containing Heterocycles. Part 50. Synthesis and Reactions of 6-Oxopyrimido[4,5-b][1,4]thiazine-7-carboxylic Acid Derivatives. -Reaction of 4-alkoxy-5-amino-6-mercaptopyrimidines (I) with bromomalonate (II) provides access to the title pyrimidothiazinecarboxylates [cf. (III), (XII)], from which a series of derivatives at the carboxyl group (amides, hydrazides, urethanes) are synthesized. Desulfurization of the pyrimidothiazine derivatives gives N-(pyrimidin-5-yl)monoamides of ethyl malonate [cf. (XI)]. -(SAFONOVA, T. S.; KEREMOV, A. F.; Chem.