Arylation of monothiobarbituric acid with arenediazonium salts

The first product under the conditions of O,S-arylation of monothiobarbituric acid is 5-aryl-hydrazonomonothiobarbituric acid. S-arylation then occurs to form the S-aryl ester of 5-arylhydrazonomonothiobarbituric acid. Further arylation leads to the O,S-diaryl esters of 5-arylhydrazonomonothiobarbituric acid. These esters are hydrolyzed under the influence of acids, alkalis, or hydrazine hydrate to thiophenols and phenols.We thank P.S. Pel'kis for his attention and interest in this research.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1271–1275, September, 1971.