Microwave Assisted Synthesis, Characterization and Antimicrobial Screening of Thiazolidin-4-one Substituted Pyrazole Derivatives

Background: This paper describes the synthesis of novel thiazolidin-4-one substituted pyrazole derivatives from the condensation reaction of hydrazide with acetophenone derivatives. Herein we describe the synthesis of fourteen compounds by microwave irradiation method. The synthesized compounds are in excellent yield by utilizing microwave irradiation heating. Objective: Compounds using different aromatic or heteroaromatic compounds should be synthesized and screened for their antibacterial activity to explore the possibility of pyrazole substituted thiazolidin- 4-ones as a novel series of antimicrobials. Methods: Synthesis of thiazolidin-4-one substituted pyrazole derivatives was carried out under microwave radiation. Results: These compounds were identified on the basis of melting point range, R-f values, IR, 1H-NMR and mass spectral analysis. These compounds were evaluated for their in vitro antimicrobial activity and their Minimum Inhibitory Concentration (MIC) was determined. Among them Comp. 4b and Comp. 4k possess appreciable antimicrobial and antifungal activities. Conclusion: A novel series of Thiazolidin-4-one substituted pyrazole were synthesized under microwave irradiation method and identified on the basis of melting point range, Rf values, IR, 1H-NMR, mass spectral data and elemental analysis. The compounds were subjected to in vitro antimicrobial screening and their Minimum Inhibitory Concentrations (MIC) were determined. Among all the tested compounds, two compounds 4b and 4k exhibited moderate to significant activity against all the tested strains of bacteria and fungus were found to have appreciable antimicrobial activities. The results of antibacterial activity showed that compounds containing electron withdrawing groups were found to be more active than the compounds containing electron releasing groups.