Electrochemical investigations on some potential antibacterials, I

Article abstract of DOI:10.1139/v95-026

Electrochemical behaviour of the medicinally important 4-(4'-sulphonamoyl)hydrazono-1-phenyl-3-methyl-2-pyrazolin-5-ones has been studied at d.m.e. and glassy carbon electrodes. At d.m.e., all six compounds exhibited a single, well-defined, four-electron wave in the pH range 2.5-12.0. Polarographic four-electron wave was found to be diffusion-controlled and irreversible. Similarly, cyclic voltammetry of these compounds at glassy carbon electrode exhibited a single peak. Peak potential sh ows shifts towards negative potential with pH, with linear-segments up to pH 8,2 and are practically pH independent at higher pH values. An anodic peak at far-off positive potential was observed in the reverse scan, indicating the irreversible nature of the electrode process. Controlled potential electrolysis and coulometric studies gave the value of n as 4.0 ± 0.1 in the pH range 2.5 to 10.0. Out of the two major end products formed, one was identified as sulphanilamide and the other as 1-phenyl-3-methyl-4-amino-2-pyrazolin-5-one on the basis of IR and NMR studies. On the basis of DCP, LSV, CV, CPE, coulometry and spectral analysis, a mechanism has been postulated for the reduction of these compounds at d.m.e. and glassy carbon electrodes.