The hydrazinolysis of heterocyclic compounds. II. 6-Amino-4-hydroxy-1-methylpyrimidine-2(1H)-thione and related compounds

Abstract

The reaction of 6-amino-4-hydroxy-1-methylpyrimidine-2(1H)-thione (3) with hydrazine is shown to follow at least three pathways to give 4- amino-5-hydrazino-1,2,4-triazole-3-thiol (1), 5-hydrazino-pyrazol-3- ol(5; R = NH₂), (4-amino-5-mercapto-1,2,4-triazol-3-yl)acetohydrazide (4) and triamino-guanidine (6). Similarly, 4,6-dihydroxy-1- methylpyrimidine-2(1H)-thione (18) yields (1) and malonyl dihydrazide (19), and (4). By contrast 4,6-diamino-1-methylpyrimidine-2(1H)-thione (21) does not follow any of these pathways. Formation of (4) represents a new type of ring transformation of pyrimidines. Mechanisms of the reactions are discussed.