UTILITY OF 4-aryl-8-arylidene - 3, 4, 5, 6, 7, 8-hexahydroquinazoline-2-thiol FOR THE SYNTHESIS OF SOME NEW HETEROCYCLES AS ANTIOXIDANT AGENTS
NADIA T. A. DAWOUD *
Department of Chemistry, Faculty of Science “Girls”, Al-Azhar University, Nasr City, Cairo, Egypt
*Author to whom correspondence should be addressed.
Abstract
The present study deals with the synthesis and reactions of 4-aryl-8-arylidene-3,4,5,6,7,8-hexahydroquinazoline-2-thiol 1a-c. Hydrazinolysis of compound 1a yielded hexahydroquinazolinyl hydrazine 2. Acetylation of compound 2 yielded [1,2,4] triazolo[3,4-b] quinazoline derivative 3. The reaction of compound 2 with diethyl oxalate and ethyl acetoacetate afforded hexahydro quinazolin-2-yl-hydrazinyl-2-oxoacetate 9 and hexahydroquinazolin-2-yl-3-oxobutane hydrazide 10. Treatment of compound 1 with chloroacetyl chloride gave tetrahydro-2H-thiazolo [2, 3-b] quinazolin-3(5H)-one 13 which was used as a key for the synthesis of a series of heterocyclic compounds (14-19). The structures of the synthesized compounds were elucidated on the basis of elemental analysis, spectral data. The antioxidant activities of some new synthesized compounds have been screened. Compounds 2, 3, 12, 13, 15, 16 and 19 showed antioxidant activity using the DPPH method.
Keywords: Quinazoline-2-thiols, triazolo [3,4-b] quinazoline derivatives, thiazolo [2,3-b] quinazoline derivatives, antioxidant activity