Synthesis, Characterization and Antidiabetic Studies of Sulfonamide Derivatives

Abstract

The treatment of 4-Amino-N-(5-methylisoxazol-3-yl)benzenesulfonamide (1) with substituted aromatic aldehydes and ketones in absolute ethanol with 2-3 drops of glacial acetic acid as a catalyst under reflux conditions afforded Schiff bases of sulfonamide derivatives (1a-1f) with yields ranging from 84% to 95%. Detailed structural analysis of the synthesized compounds was carried out using infrared, 1H, and 13C nuclear magnetic resonance spectroscopic techniques. For instance, the characteristic imine (HC=N-) proton signal in compounds 1a-1c, derived from aldehydes, was observed within a chemical shift range of 8.56 to 8.73 ppm in the 1H-NMR spectrum. In contrast, this signal was absent in compounds 1d-1f, which were derived from aromatic ketones. Similarly, in the 13C-NMR spectra, signals corresponding to the carbonyl groups of compounds 1a, 1d, 1e, and 1f were detected in the range of 169.3 to 171.7 ppm. The antidiabetic potential of these compounds was explored using both in silico and in vivo methods. Molecular docking was performed against dipeptidyl dipeptidase IV (DPP-IV) to select hit molecules for density functional theory calculations, ADMET assessment, and in vivo antidiabetic studies. Diabetes was induced in normoglycaemic rats with streptozotocin (65 mg/kg), and the hit molecules were administered. Based on the molecular docking and density functional theory calculations, 1d and 1e were selected as the hit molecules. Compounds 1d and 1e produced 88% and 79% hyperglycaemia-lowering activity, respectively, and were comparable (p > 0.05) with glibenclamide (5 mg/kg). Based on the in silico and in vivo results, the synthesised compounds (1d and 1e) may be promising drug candidates for the management of diabetes.