Synthesis and biological evaluation of (3-arylisoxazol-5-yl)methyl 6-fluoro-4-oxo-4H-chromene-2-carboxylates as antioxidant and antimicrobial agents

A series of novel (3-arylisoxazol-5-yl) methyl 6-fluoro-4-oxo-4H-chromene-2-carboxylate derivatives (C-1-C-12) were synthesized by the Cu(I)-catalyzed reaction of in situ generated nitrile oxides with prop-2-ynyl 6-fluoro-4-oxo-4H-chromene-2-carboxylate in good yields and their antioxidant and antimicrobial activities were investigated. Among all the synthesized compounds, C-1 (IC50: 16.43 +/- 0.57 mu M) and C-12 (IC50: 15.98 +/- 0.72 mu M) registered good antioxidant activity as compared to the standard drug trolox. Compounds C-1, C-3 and C-6 registered very good inhibition against all the tested Gram-positive and Gram-negative bacterial strains with MIC values ranging from 9.375 to 37.5 mu g mL(-1). Compounds C-7-C-11 registered good inhibition against Bacillus subtilis and Staphylococcus aureus with MIC values ranging from 18.75 to 37.5 mu g mL(-1). Compounds C-10 and C-11 against Pseudomonas aeroginosa showed more prominent activity than the standard drug penicillin (MIC: 12.5 mu g mL(-1)) with an MIC value of 9.375 mu g mL(-1) (approximate to 1.33-fold more potent than penicillin). Compounds C-7-C-9 registered good to moderate antifungal activity against the four tested fungal strains with MIC values ranging from 18.75 to 37.5 mu g mL(-1).