Synthesis and Characterization of Novel 2-(1,2,3-Triazol-4-yl)-4,5-dihydro-1 H -pyrazol-1-yl)thiazoles and 2-(4,5-Dihydro-1 H -pyrazol-1-yl)-4-(1 H -1,2,3-triazol-4-yl)thiazoles.

Reactions of 1-(5-methyl)-1 H -1,2,3-triazol-4-yl)ethan-1-ones and benzaldehydes in ethanol under basic conditions gave the corresponding chalcones. Reactions of the chalcones combined with thiosemicarbazide in dry ethanol containing sodium hydroxide afforded the corresponding pyrazolin- N -thioamides. Reactions of the synthesized pyrazolin- N -thioamides and several ketones (namely, ethyl 2-chloro-3-oxobutanoate, 2-bromoacetylbenzofuran, and hydrazonoyl chloride) gave the corresponding novel 2-(1,2,3-triazol-4-yl)-4,5-dihydro-1 H -pyrazol-1-yl)thiazoles in high yields (77-90%). Additionally, 2-(4,5-dihydro-1 H -pyrazol-1-yl)-4-(1 H -1,2,3-triazol-4-yl)thiazoles were obtained in high yields (84-87%) from reactions with N -pyrazoline-thioamides and 4-bromoacetyl-1,2,3-triazoles under basic conditions. The structures of six of the newly synthesized heterocycles were confirmed by X-ray crystallography.