Synthesis and biological evaluation of 2 (3-arylisoxazol-5-yl)methyl 6-fluoro-4-oxo-4H-chro3 mene-2-carboxylates as antioxidant and antimicrobial agents

Abstract

A series of novel (3-arylisoxazol-5-yl)methyl 6-fluoro-4-oxo-4H-
-chromene-2-carboxylate derivatives (C1–C12) 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, C1 (IC50: 16.43±0.57 µM) and C12 (IC50:15.98±0.72 µM) registered good antioxidant activity as compared to the standard drug trolox. Compounds C1, C3 and C6 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 µg mL-1. Compounds C7–C11 registered good inhibition against Bacil­lus subtilis and Staphylococcus aureus with MIC values ranging from 18.75 to 37.5 µg mL-1. Compounds C10 and C11 against Pseudomonas aeroginosa showed more prominent activity than the standard drug penicillin (MIC: 12.5 µg mL-1) with an MIC value of 9.375 µg mL-1 (≈1.33-fold more potent than penicillin). Compounds C7–C9 registered good to moderate antifungal activity against the four tested fungal strains with MIC values ranging from 18.75 to 37.5 µg mL-1.