Synthesis, Characterization and Biological Evaluation of Novel 2,4-Dioxothiazolidine Derivatives as Potential Antimicrobial Agents

Objective:  To develop a series of 2,4-dioxothiazolidine derivatives of aryl substituted cinnamic acid, characterization by elemental and spectral (IR,  1 H-NMR) studies and antimicrobial study. Method:  All compounds were synthesized from pure & standard substrates. Reactions were monitored by TLC & Melting points were determined by decibel melting point apparatus. The IR spectra were recorded on Perkin Elmer IR spectrophotometer using KBr pellets. Proton nuclear magnetic resonance spectra ( 1 H NMR) were recorded on Brucker Avance II 400 NMR spectrophotometer. Antimicrobial activity was performed by measuring zone of inhibition. Results:  All the synthesized compounds were purified and give very good spectra of IR & NMR. Compunds were studied for their antimicrobial activity in comparison to the standard drugs. Thz 9 was found the most active compound in this series, where Ciprofloxacin was used as a standard drug for antibacterial activity and Clotrimazole for antifungal activity. Conclusion:  Compound Thz9 exhibited highest antimicrobial activity due to substitution of aryl ring by electron releasing methoxy groups at -ortho and -para position. Compound Thz9 was found more active than all other dimethoxy substituted compounds, the reason behind it may be that dimethoxy substitutions at - ortho  and - para  position on aryl ring enhanced the binding of molecule with the target. Almost in all compounds propyl ester has higher activity than methyl, ethyl esters, which means that heavy carbon chain ester increase the antimicrobial activity.