Product diversity by changing the electrode potential. Synthesis, kinetic evaluation and antibacterial activity of arylsulfonyl-4,4'-biphenol and bis-arylsulfonyl-4,4'-biphenol derivatives

Abstract

The electrochemical synthesis of arylsulfonyl-4,4′-biphenol (ASB) and bis-phenylsulfonyl-4,4′-biphenol (BASB) derivatives was carried out via the electrochemical oxidation of 4,4′-biphenol in the presence of arylsulfinic acids as nucleophiles using a carbon anode. Our data demonstrate that the arylsulfinic acids participate in Michael type addition reaction with the electrogenerated 4,4′-diphenoquinone, converts it to the arylsulfonyl-4,4′-biphenol or bis-phenylsulfonyl-4,4′-biphenol derivatives depends on electrode potential. The arylsulfonyl-4,4′-biphenols were evaluated for their in vitro antibacterial activity against Escherichia coli (E. coli) ATCC 35218 (Gram-negative) and Staphylococcus aureus (S. aureus) ATCC 6538 (Gram-positive). It was found that the tested compounds were more active against gram-positive than gram-negative bacteria. It was also found that the antimicrobial activity of ASB derivatives to vary in the order ASB-CH3>ASB-Cl>ASB-H. Furthermore, based on the EC mechanism, the observed homogeneous rate constants (kobs) of the reaction of 4,4′-diphenoquinone with arylsulfinic acids were estimated by comparing the experimental cyclic voltammograms with the digital simulated results in various pH values.