Abstract

S. S. El-Sakka¹, M.A.E. Hashash¹, I.I. Abd El-Gawad¹ and G. E. Ahmed²

Reaction of 2-phenyl-6,8-dibromo-3,1-benzoxazine-4-one (1) with benzoylhydrazine, hydroxylamine, ammonia and sodium azide gave the corresponding 6,8-dibromo-3-substituted- 4(3H)quinazolinones (2, 3 and 8), tetrazole derivative (6) and 1-benzoylbenzimidazole-2-one. Acetylation and alkylation of 3 with acetyl chloride and ethyl chloroactate yielded the corresponding 3-substituted- 4(3H)-quinazolinones (4 and 5). Chlorination of 8 with POCl3/ PCl5 afforded the corresponding 4- chloro-6, 8-dibromoquinazoline (9). Treatment of 9 with mercapto compounds, aromatic amines, piperidine and active methylene compounds gave the corresponding 4-substituted quinazolines (10, 11, 12 and 14). Reaction of 9 with thiourea, sodium azide and hydrazine hydrate yielded the corresponding 4(3H)-quinazoline-4-thione (13), tetrazolo quinazoline (15) and 4-hydrazino-quinazoline (16). Triazoloquinazoline (18) was prepared via cyclocondensation of compound 16 with carbon disulphide in presence of alcoholic potassium hydroxide. Some synthesized compounds also exhibited antimicrobial activities.

Synthesis; biological activity; nitrogen heterocycles

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