Synonyms: s-Triazolo[1,5-a]pyrimidin-7-ol,5-methyl-2-(methylthio)- (7CI); 2-Methylmercapto-4-hydroxy-6-methyl-1,3,3a,7-tetraazaindene;4-Hydroxy-6-methyl-2-(methylthio)-1,3,3a,7-tetrazaindene;4-Hydroxy-6-methyl-2-methylmercapto-1,3,3a,7-tetraazaindene; NSC 509227