Efficient, One-Pot Synthesis of Triazolothiadiazinyl-pyrazolone and Pyrazolyl-triazolothiadiazine Derivatives via Multicomponent Reaction

A one-pot, multicomponent reaction of 3-(2-bromo acetyl)coumarins, 4-amino-5-hydrazino-4H-[1,2,4]triazole-3-thiol, and different derivatives of ethyl 2-(2-(aryl)hydrazono)-3-oxobutanoates provide an efficient and direct method for the synthesis of 4-(arylydrazono)-3-methyl-1-(6-(coumarin-3-yl)-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-3-yl)-1H-pyrazol-5(4H)-ones (<b>4a–h</b>). A similar methodology was also developed for the synthesis of pyrazolyl-triazolothiadiazines (<b>9a–f</b>) using acetyl acetone, 4-amino-5-hydrazino-4H-[1,2,4]triazole-3-thiol, and different derivatives of phenacylbromide. The resulting products were characterized by analytical and spectral data.