Reactivity of 2-ethoxyquinazolin- 4-yl hydrazine and its use in synthesis of novel quinazoline derivatives of antimicrobial activity

The reactions of 2-ethoxy-4-hydrazinoquinazoline 2 with diethyl oxalate and ethyl chloroacetate gave 6-ethoxy-2H-[1,2,4]triazino[4,3-c]quinazoline-3,4-dione 3 and 6-ethoxy-2,3-dihydro-4H-[1,2,4]triazino[4,3-c]quinazolin-4-one 4 respectively. A series of 5-ethoxy-2-X-[1,2,4]triazolo[1, 5-c]quinazolines 5a-d was also produced by reacting 2 with the acid chlorides namely: benzoyl, crotonyl, cinnamyl and 2-furoyl chlorides via Dimroth rearrangement. Also, 2 reacted with ethyl chloroformate giving 6. Condensation of 2 with acetone gave Schiff base 7, and with monosaccharides gave the sugar hydrazones 8a-e which were thereafter acetylated giving the corresponding 9a-e. Cyclization of 8a-e by iron(III) chloride gave triazoloquinazolines 10a-e acyclic C-nucleosides which, by acetylation, afforded 11a-e. All products were confirmed by elemental, IR, MS, and 1H-NMR analysis. Products 8-11 were chosen for biological screening test against gram(+ ive) and gram(- ive) bacteria.