Convenient synthesis and characterization of new 1,3,4-thiadiazoles and thiazoles incorporating thiophene moiety

Reaction of substituted acetylpyrazole with methyl hydrazinecarbodithioate using hydrochloric acid as a catalyst in absolute ethanol afforded methyl 2-(1-(1H-pyrazol-4-yl)ethylidene)hydrazinecarbodithioate H-pyrazol-4-yl)ethylidene)hydrazinecarbodithioate derivative. Refluxing of the latter product with hydrazonoyl halides in absolute ethanol in the presence of triethylamine afforded the corresponding 1,3,4-thiadiazoles. Heating the same acetylpyrazole with hydrazinecarbothioamide in refluxing ethanol using hydrochloric acid as a catalyst afforded 2-(1-(1H-pyrazol-4- H-pyrazol-4- yl)ethylidene)hydrazinecarbothioamide derivative. The reaction of the latter compound with omega- bromoacetophenone derivatives in absolute ethanol at reflux afforded the corresponding thiazole derivatives.