Hydrolysis products of menazon

Abstract

Extensive breakdown of menazon (I; X = S) occurs on heating with dilute hydrochloric acid (1:1). The formation of 2,4-dihydroxy-6-methyl-1,3,5-triazine (IV) under these conditions was unexpected; elemental sulphur was eliminated in this reaction, and both amino groups hydrolysed to ammonia. 2,4-diamino-6-mercaptomethyl-1,3,5-triazine (III; Y = SH) is the main product formed on milder acid hydrolysis, whilst methanolic potassium hydroxide treatment of menazon yields 2,4-diamino-6-methylthiomethyl-1,3,5-triazine (III; Y = MeS). The secondary dithiophosphate ester, or des-methyl menazon (II), is formed in a trans-methylation reaction of menazon with sodium OO-dimethylphosphorodithioate. The preparation and characterisation of hydroxyamino and dihydroxytriazine derivatives related to menazon are also described.