New quinoxalin-1,3,4-oxadiazole derivatives: Synthesis, characterization, in vitro biological evaluations, and molecular modeling studies

Abstract

A new series of quinoxalin-1,3,4-oxadiazole (10a-l) derivatives was synthesized and evaluated against some metabolic enzymes including human carbonic anhydrase (hCA) isoenzymes I and II (carbonic anhydrases I and II), cholinesterase (acetylcholinesterase and butyrylcholinesterase), and alpha-glucosidase. Obtained data revealed that all the synthesized compounds were more potent as compared with the used standard inhibitors against studied target enzymes. Among the synthesized compounds, 4-fluoro derivative (10f) against hCA I, 4-chloro derivative (10i) against hCA II, 3-fluoro derivative (10e) against acetylcholinesterase and butyrylcholinesterase, and 3-bromo derivative (10k) against alpha-glucosidase were the most potent compounds with inhibitory activity around 1.8- to 7.37-fold better than standard inhibitors. Furthermore, docking studies of these compounds were performed at the active site of their target enzymes.