Acryloyl isothiocyanate skeleton as a precursor for synthesis of some novel pyrimidine, triazole, triazepine, thiadiazolopyrimidine and acylthiourea derivatives as antioxidant agents
Azza A. El‐Badawy, Amna S. Elgubbi, Eman A. E. El‐Helw
Abstract
The reactions of 2-cyano-3-pyrazolylpropenoyl isothiocyanate derivative 2 with some mono- and bidentate nucleophiles namely, dodecan-1-amine, 6-aminothiouracil, hydrazine, phenylhydrazine, phenylurea, semicarbazide, and thiosemicarbazide, in addition to some derivatives of hydrazides, have been investigated to obtain some valuable heterocyclic skeletons gathering with a pyrazole core, viz. pyrimidine, triazole, triazepine, thiadiazolopyrimidine as well as acylthiourea derivatives. Hydrazinolysis of 2 was found to provide a mixture of thiosemicarbazide, diheterylazine, and triazepine derivatives. Treatment of 2 with phenylhydrazine was mainly dependent on the reaction conditions to produce a mixture of pyrimidinethione and triazole derivatives at room temperature or the triazepine derivative at heating conditions. The antioxidant activity screening of these compounds disclosed that pyrimidinethione derivatives 9 and 13 exhibited the most potency.