Ultrasound-assisted synthesis of auxiliary pyrazoline integrated thiazole, thiazolone derivative and their biological evaluation

In this paper, we describe a simple catalyst-free protocol for the synthesis of thiazole, thiazolone integrated pyrazole derivatives, under ultra-sonication technique. Thiazolone derivatives (5a, 5e, 5i, 5d, 5h, 5l)were derived from [3+2] cyclocondensation reaction between carbothioamide pyrazoline (4a-c) as S-N bi-nucleophile with DMAD/DEAD. The target molecules (5b, 5f, 5j,5c, 5g, 5k)were synthesized by the reaction of (4a-c) with the substituted bromoethanone. Formation of the products was confirmed by FT-IR, 1H-NMR, 13C-NMR, LCMS analysis. Docking studies were carried out against the antimicrobial target (Acinetobacterbaumannii penicillin) to know the interaction of the molecules (ligands) with the docked target. Among the docked compounds thiazolone derivative (5d) showed theminimum binding energy of -9.08 kJ/mol with ligand efficiency of -0.23. All the synthesized compounds were examined primarily for their in-vitro antibacterial and antioxidant activity (IC50). Compound (5g)(18±0.0) and (5d)(19.5±0.5) showed significant bacterial inhibition against E.coli and S.aureus. Compound (5k) (16.57) showed substantially DPPH free radical inhibition activity as compared to the reference drug Ascorbic acid.