Heteropoly Acid Catalyzed Selective Cyclization of 6-Alkyl-3-propargylmercapto-1,2,4-triazin-5(2H)-one

Abstract

Cyclization of 6-alkyl-3-propargylmercapto-1,2,4-triazin-5(2H)-one, derivatives (2) in the presence of Keggin heteropoly acids, H₃PW₁₂12O₄₀, H₃PMo₁₂O₄₀, H₄SiW₁₂O₄₀ and lacunary Keggin structure (K₇PMo₂W₉O₄₀) afforded 3 (3a = 6-dimethyl-7H-thiazolo[2,3-b][1,2,4]-triazin-7-one and 3b=6-ethyl-3-methyl-7H-thiazolo[2,3-b][1,2,4]-triazin-7-one) in high yields and short reaction times