Novel chitosan derivatives of 2-imidazolecarboxaldehyde and 2-thiophenecarboxaldehyde and their antibacterial activity

Abstract

Chitosan was synthesized from chitin; extracted from prawn shells’ powder via deacetylation and physicochemical properties were studied. Novel chitosan derivatives of 2-imidazolecarboxaldehyde and 2-thiophenecarboxaldehyde were synthesized by refluxing equimolar quantities of respective aldehyde with chitosan. These functionalized chitosan derivatives were characterized by Fourier transform infrared (FTIR), ¹³C-nuclear magnetic resonance (¹³C-NMR) spectroscopy, elemental analysis, X-ray diffraction (XRD), thermogravimetric analysis (TGA) and differential thermal analysis (DTA) and their antibacterial activity was explored. Chitosan derivative of 2-thiophenecarboxaldehyde was found active against Escherichia coli.

GRAPHICAL ABSTRACT

Keywords:

• Antibacterial activity
• chitosan-imidazole
• chitosan-thiophene
• ¹³C-NMR spectroscopy
• FTIR
• TGA

Acknowledgments

The authors gratefully acknowledge Indian Institute of Science, Bangalore, India for providing solid state ¹³C-NMR spectra and Jawaharlal Nehru University (JNU), India for providing XRD and TGA analysis data. Indian Institute of Technology (IIT), Chennai, India is acknowledged for providing elemental analysis and also XRD data. The authors are grateful to Dr. Bishnu P. Marasini, Department of Biotechnology, National College, Kathmandu, Nepal for antibacterial assay of the synthesized compounds. We are also thankful to Mr. Tara Dutta Bhatta, Department of Plant resources, Thapathali, Kathmandu, Nepal for providing FTIR spectra of the synthesized compounds.