Synthesis, bioactivity screening and docking analysis of thiazole derivatives containing quinoline moieties.

Abstract

Thiazole, the heterocyclic compound is an important scaffold of azaheterocycles family. Heterocyclic nucleus containing thiazole Schiff bases imparts an important function in medicinal chemistry and serves as a key template for the development of various therapeutic agents. In our present work, three thiazole Schiff base derivatives containing quinoline moieties 1b-3b were synthesized by two step reactions. Firstly, three thiosemicarbazone derivatives la-3a were synthesized using aldehydes substituted quinoline and thiosemicarbazide. Cyclization of la-3a with 3-chloroacetylacetone afforded the corresponding thiazoles Schiff bases 1b-3b. The synthesized analogs characterization was elucidated by spectral analyses (IR, 1H NMR, 13C NMR, COSY, HSQC and HMBC). All the synthesized compounds were screened for their antimicrobial activity towards three gram-positive bacteria Bacillus Cereus, Staphylococcus aureus and Bacillus magaterium, three gram-negative bacteria Klebsiella pneumonia, Pseudomonas aeruginosa and Escherichia coli and two fungal strains Trichoderma harzianum and Aspergillus niger were used in this study revealed that some compounds displayed moderate to good antimicrobial activities compared to standard Ampicillin & Amphotericin B in Agar disc diffusion technique. Compounds 1b & 3b revealed comparable antibacterial activities against S. aureus, B. Cereus, K. pneumonia and E. coli, compound 2b showed potential antibacterial activities against S. aureus, K. pneumonia, and E. coli with standard ampicillin. In antifungal screening, compounds 1b & 3b showed moderate to potential antifungal activities against the fungi Aspergillus niger with standard amphotericin b. From our research, we observed that compounds 1b & 3b might be used as potential antibacterial and antifungal drugs in future.