Synthesis and antimicrobial evaluation of some pyrazolo-thiazolyl alkoxy-1H-isoindole-1, 3(2H)-dione derivatives

Abstract

1,3-Thiazolidine-2,4-dione 2 has been synthesized by the cyclisation reaction of thiourea and chloroacetic acid in the presence of ethanol. The reaction of compound 2 with substituted aromatic aldehyde afforded the corresponding derivatives of substituted 5-benzylidene-1,3-thiazolidinone-2,4-dione 3a–d, which upon reflux with ω-bromoalkoxyphthalimide gave 2-{[-5-(substituted benzylidine)-2,4-dioxo-1,3-thiazolidine-3-yl]alkoxy} -1H-isoindole-1,3(2H)-dione 4a–i. Further, compounds 4a–i were treated with phenyl hydrazine and 2,4 dinitro phenyl hydrazine in the DMF to yield the title compound 2-[5-oxo-2,3-substituted diphenyl-2H-pyrazolo[3,4-d][1,3]thiazol-6(5H)-yl)alkoxy]-1H-isoindole-1,3(2H)-dione 5a–r. Structures of newly synthesized compounds were established based on elemental analysis, IR, ¹H NMR and mass spectral data. Synthesized compounds have been assayed for their antibacterial activities against B. subtilis, K. pneumoniae, P. aeruginosa and S. aureus and antifungal activities against A. fumigatus and C. albicans.

Keywords:

• 2-Iminothiazolidinones
• 5-Benzylidine-1,3-thiazolidinone-2,4-dione
• Pyrazolo[3,4-d] [1,3]thiazol
• Alkoxyphthalimides
• Bio-assay

Acknowledgements

The authors are thankful to The Head, Department of Chemistry, M. L. Sukhadia University, Udaipur for providing laboratory facilities, The Director, CDRI, Lucknow for providing spectral and analytical data and Incharge, Department of Biotechnology, M. L. Sukhadia University, Udaipur for antimicrobial studies. One of the authors (VKS) is thankful to CSIR, New Delhi for providing essential financial support.