Abstract

A series of 4-[4-(substitutedaryl/heteroaryldiazenyl]-N-(5-methylisoxazol-3-yl)benzene sulphonamide derivatives (4a-4f) were designed and synthesized coupling a mixture of diazotized sulfamethoxazole with six different phenolic and enolic compounds in an in situ reaction. The structural environment of synthesis of each molecule was confirmed by Fourier-transform infrared spectroscopy, proton nuclear magnetic resonance and elemental analysis. These derivatives were further screened in various biological assays in vivo for analgesic and antiinflammatory activities and in vitro for antioxidant and antimicrobial activities. When tested for analgesic activity at a dose of 50 mg/kg, compounds 4-((2-hydroxynaphthalen- 1-yl)diazenyl)-N-(5-methylisoxazol-3-yl)benzene sulphonamide (4d) and 4-((4-hydroxy-5-isopropyl-2- methylphenyl)diazenyl)-N-(5-methylisoxazol-3- yl)benzene sulphonamide (4f) showed 58.33 and 57.76 % of pain inhibition, respectively. These two molecules also exhibited significant antioxidant activity at 10 and 50 μg/μl. The compound 4-[(4-hydroxy-2-oxo-2H-chromen-3-yl)diazenyl]-N-(5-methylisoxazol- 3-yl)benzene sulphonamide (4a) exhibited antibacterial activity against Staphylococcus aureus resistance, Candida albicans and DescriptionCryptococcus neoformans at a concentration of 31.25 μg/ml. The analgesic action of these synthesised analogues was predicted in molecular docking experiments with a specific target protein, cyclooxgenase-2 of Mus musculus and results indicated all tested compounds to exhibit good binding interaction with the active site amino acid of the target enzyme.