Synthesis and Antimicrobial Activity of Some New Quinoxaline Derivatives

Abstract

2-Chloro-3-methylquinoxaline was selected as a nucleus around which various molecular transformations were performed to obtain new compounds expected to possess optimized antimicrobial activity. As very little work regarding attachment of ether linkages replacing chlorine at C-2 has been reported, it was thought worthwhile to synthesize various quinoxaline derivatives by replacing the C2 chlorine with an ether linkage attached to a benzene ring possessing an aldehyde or a free amino group which can be further reacted with aromatic amines and aromatic aldehydes, respectively, to yield new Schiff bases containing quinoxaline moieties. Thus the compounds 4-(2-methylquinoxalinyloxy) benzaldehyde (4), 2-[4-(substituted-benziminomethyl)-phenoxy]-3-methyl quinoxalines 5a–e, 4-(2-methyl-quinoxaline-3-yloxy)benzamine (6) and 4-(2-methylquinoxalin-3-yloxy)-N-substituted benzylidine benzamines 7a–e were synthesized and tested for their antimicrobial activity. The structures of the compounds were confirmed on the basis of their elemental and spectral data.

6-Methyl-1,4-bis[(pyridin-2-yl)methyl]quinoxaline-2,3(1H,4H)-dione

“…Quinoxalines and their derivatives are a varied class of nitrogen-containing heterocyclic compounds, which display various pharmacological and biological activities, such as anticancer (Carta et al, 2006), antimalarial (Guillon et al, 2004), antiviral (Fonseca et al, 2004), antibacterial (El-Sabbagh et al, 2009), antimicrobial (Singh et al, 2010), antiinflammatory (Wagle et al, 2008) and antiprotozoal (Hui et al, 2006). In this work, we report the synthesis of a new quinoxaline derivative by the reaction of 2-picolyl chloride with 6-methyl-1,4-dihydroquinoxaline-2,3-dione in dimethylformamide in the presence of potassium carbonate and a catalytic quantity of tetra-n-butylammonium bromide.…”

Synthesis and application of polyvinylimidazole-based Br{\o}nsted acidic ionic liquid grafted silica as an efficient heterogeneous catalyst in the preparation of quinoxaline derivatives

“…They are well known in the pharmaceutical industry as important precursors with biological activities such as antimicrobial, 28 45 However, a number of these methods suffer from some limitations such as using strong acidic conditions, tedious work-up procedures, low yield, and long reaction times. Thus, it seems desirable to find a more efficient and milder protocol for the synthesis of quinoxalines.…”

Present status of quinoxaline motifs: Excellent pathfinders in therapeutic medicine

“…Out of 2,3-bis(bromomethyl)quinoxalines evaluated by Ishikawa and coworkers, 119 showed the widest antifungal activity spectrum [124] while 120 was reported to be a fruitful matrix for further biological evaluation based on its wide zones of inhibition against C. albicans and S. cerevisiae [125]. Moreover, the result of preliminary in vitro screening of Schiff base 121 against A. niger and C. albicans showed moderate activity [126]. The anticandida tests conducted on various strains of Candida spp in order to determine ring extension effect on the antifungal activity, showed tricyclic pyridoquinoxaline 122 to be the most active with MIC value = 31.25 µg/mL [127].…”