Synthesis and antibacterial activity of fused 1, 2, 4-triazolo[4, 3-a]quinoxaline and oxopyrimido[2', 1':5, 1]-1, 2, 4-triazolo[4, 3-a]quinoxaline derivatives.

A new series of potential antibacterial agents having tricyclic 1, 2, 4-triazolo-[4, 3-a] quinoxaline fused with one or more heterocyclic rings was synthesized via several routes. The tricyclic 1-amino-4-chloro-1, 2, 4-triazolo[4, 3-a] quinoxaline (2 ) and tetracyclic 1, 6-diamino-bis-1, 2, 4-triazolo[4, 3-a:3, 4-c] quinoxaline (3) were synthesized from 2, 3-dichloroquinoxaline (1) with two or four equivalents of thiosemicarbazide, respectively. Compound 2 was allowed to react with different aldehydes, alkoxides, cyclic amines, phenyl isothiocyanate, and t-butyl isocyanate to afford the corresponding quinoxaline derivatives.