Abstract
In this work, a series of 3,4-dihydro-4-oxo-1,2,3-benzotriazines that incorporate either 5-substituted 1,2,4-triazolo[4,3-c]quinazoline or 4-substituted thiazole at the 3-position was synthesized. These compounds were prepared through reaction of isatoic anhydride with 3-amino-5-chloro-1,2,4-triazolo[4,3-c]quinazoline or 2-amino-4-ethoxycarbonyl-thiazole to give the corresponding 2-amino-N-substituted benzamides 3 and 12 respectively. These intermediates were cyclized using nitrous acid to achieve the formation of the initial benzotriazines 4 and 13 respectively. The chlorine atom in compound 4 was substituted with different cyclic amines and some alkoxides. On the other hand, the ester group in compound 13 was subjected to cyclization under different conditions to give various heterocyclic residues as 1,3,4-oxadiazole, 1,3,4-thiadiazole, and 5-thioxo-1,2,4-triazole. The new compounds were tested for their antibacterial activities where some of them exhibited good potency.