Azines and Azoles:CXXVIL* 5-Phenyl-7H-[1,2,4]triazolo-[5,1-b][1,3]thiazin-7-ones:Synthesis and Structure

摘要

Reactions of 1-acylthiosemicarbazides with methyl 3-phenylprop-2-ynoate provide a new one-step procedure for the synthesis of 2-substituted 5-phenyl-7H-[1,2,4]triazolo[5,1-b][1,3]fhiazin-7-ones.The product structure was determined on the basis of scalar spin-spin coupling constants ~2J(~1H-~(15)N)and ~3J(~1H-~(15)N)in the ~1H and ~(15)N NMR spectra and was proved by X-ray analysis.Methyl 3-phenylprop-2-ynoate reacted with 1-acetylthiosemicarbazide in ethanol in the presence of H2SO4 to give 3-mefhyl-7-phenyl[1,2,4]triazolo[3,4-b]-[1,3]thiazin-5-one as the only product.