A facile microwave enhanced synthesis of sulfur-containing 5-membered heterocycles derived from 2-mercaptobenzothiazole over ZnCl ₂/DMF and antimicrobial activity evaluation

Abstract

An efficient and extremely fast procedure for the synthesis of 4-thiazolidinones 4a–j by the reaction of arylidene-[(2-benzothiazolylthio)-acetamidyl] 3a–j with thioglycolic acid in DMF in the presence of a catalytic amount of anhydrous ZnCl ₂ under microwave irradiation is described. A considerable increase in the reaction rate has been observed with better yield in microwave technique. All the compounds have been screened for their antifungal activity against Candida albicans (ATCC-64550), Candida krusei (ATCC-14243) and Candida parapsilosis (ATCC-22019) and antibacterial activity against Escherchia coli (Gram−ve) (ATCC-8739), Staphylococcus aureus (Gram+ve) (ATCC-6538) and Bacillus substilis (Gram+ve) (ATCC-6633). The structures of the synthesised compounds 4a–j have been characterized on the basis of their elemental analysis and spectral data.

Keywords:

• 4-Thiazolidinones
• Heterocyclization
• Microwave effect
• Antimicrobial activity
• Anhydrous ZnCl ₂/DMF

Acknowledgements

One of the authors (KGD) is thankful to the Head of Chemistry and Bioscience Department of Veer Narmad South Gujarat University, Surat; Gujarat Council On Science & Technology (Grant no. GUJCOST/200389/MRP/2003-04/10689), Gandhinagar for financial assistance and Central Drug Research Institute, Lucknow for spectral analysis.