1,2,3-Triazoles based 3-substituted 2-thioquinoxalines: Synthesis, anti-bacterial activities, and molecular docking studies

Abstract

Abstract New 1,2,3-triazoles based on 3-Substituted 2-thioquinoxalines were synthesized via a copper-catalyzed click reaction. The new 1,2,3-triazoles were screened for their in vitro antibacterial activities and were subjected to molecular docking studies. The starting materials included, 3-substituted-2-propargylthioquinoxalines were prepared from 2,3-dichloroquinoxaline, aliphatic amines, sodium sulfide, and propargyl bromide. The click of 2-propargythioquinoxalines with aryl azides catalyzed by copper(II) salen complex afforded novel 1,2,3-triazole-linked thioquinoxalines derivatives. The use of salen copper(II) complex as a catalyst, increased the reaction rate and reduced the loading of the toxic copper species. Results obtained from the in vitro anti-bacterial activities of the synthesized compounds revealed that compounds 7e, 7g, and 7k are active against Bacillus subtilis and Micrococcus luteus bacteria. Furthermore, in silico molecular docking results stipulated a sign of good correlation between experimental activity and calculated binding affinity. Docking studies proved 7e as the most potent compound. In addition, the binding maps exhibited activities that may attribute to the existence of electron donating and lipophilic group at para position of phenyl ring and hydrophobic interactions and hydrogen bond with the protein active sites.