A series of quinoxaline derivatives were synthesized by doing molecular modifications at C-3 methyl group of 2-hydroxy-3-methylquinoxaline nucleus. The synthesis was initiated by bromination followed by attachment of p-hydroxy bezaldehydes to 3-methyl group to synthesize 3(4-formyl phenoxymethyl)-quinoxaline-(1H)-2-one as new intermediate and condense it with substituted aromatic amines to afford the synthesis of Schiff bases of 3-methylquinoxalin-2(1H)-one. The new compounds (GG1, GG2, GG3, GG4 and GG5) have been synthesized by treating o-phenylene-diamine with ethyl pyruvate to yield
3-methylquinoxaline 2-one, which on bromination afforded the synthesis of 3-bromomethyl quinoxaline-2-one. Finally 3-bromomethyl quinoxaline-2-one was treated with 4-hydroxy benzaldehyde to yield the synthesis of 3-(-4-formyl phenoxy methyl)-quinoxalin 2(1H)-one (GG1), which was treated with different substituted aromatic amines to yield the synthesis of 3-((4-(substituted-phenylimino)-methyl)-phenoxy)-methyl)quinoxalin-2(1H)-one (GG2,GG3,GG4 and GG5). The structures of pure compounds were characterized on the basis of IR and 1H-NMR spectral analysis. All the synthesized compounds were evaluated for antimicrobial activity.
2-Hydroxy-3-methylquinoxaline, 3-Bromomethyl quinoxaline-2-one, p-Hydroxy bezaldehydes, 3-((4-(substituted-phenylimino)-methyl)-phenoxy)-methyl)quinoxalin-2(1H)-one, antimicrobial activity