Synthesis of novel furobenzopyrone derivatives and evaluation of their antimicrobial and antiinflammatory activity

Abstract

Certain 4'-(4''-substituted phenyl)-4-methylfurobenzopyrones were synthesized and evaluated for antibacterial activity. Six of the synthesized compounds were also screened for their antiinflammatory activity. Substituted resorcinols were condensed with ethyl acetoacetate to afford different coumarins (2a-c). Various substituted phenacyl bromides (4a-g) were prepared by the bromination of para-substituted acetophenones. The coumarins (2a-c) and phenacyl bromides (4a-g) were condensed to give oxoethers (5a-s). These were cyclised by using 1 M sodium hydroxide to afford the desired furobenzopyrone derivatives (FCa-s). All the compounds have been evaluated for their antibacterial activity against different strains of gram positive and gram negative bacteria. All the compounds have shown good activity against Pseudomonas aeruginosa . Compounds, 3-(4-chlorophenyl)-5-methylfuro-[3,2-g][1]benzopyran-7-one, 3-(4-chlorophenyl)-5,9-dimethylfuro[3,2-g][1]benzopyran-7-one and 4,5-dimethyl-3-phenylfuro[3,2-g][1]benzopyran-7-one (FCe, FCi, FCn) were active against E. coli . A few compounds showed moderate activity against Bacillus subtilis also. Antiinflammatory activity of six selected compounds was also tested using the carrageenan-induced rat paw oedema method. Among them, 5-methyl-3-p-tolylfuro[3,2-g][1]benzopyran-7-one (FCg) showed excellent activity. 5-Methyl-3-phenylfuro[3,2-g][1]benzopyran-7-one (FCa) and 4,5-dimethyl-3-(4-nitrophenyl)-furo[3,2-g][1]benzopyran-7-one (FCc) showed activity comparable to that of the standard drug ibuprofen.