Main author: Sankar Rathinam
Institution or Company: University of Iceland
Co-Authors, Institution or Company:
Martha Á Hjálmarsdóttir, University of Iceland. Mikkel B. Thygesen, University of Copenhagen. Már Másson, University of Iceland.
Introduction: “Click chemistry” is a term which was first described by K. B. Sharpless. To describe reactions that afford products in high yields and in excellent selectivity by carbon-hetero bond formation this methodology is an eco-friendly reaction. Chitosan is derived from chitin and it is an abundant, renewable polysaccharide which exhibits attractive biopolymer properties for many biomedical applications such as non-toxicity, biocompatibility, and biodegradability.
Methods: Design and synthesis of a new class of chitosan derivatives where all C-2 primary amino groups have been converted to aromatic 1,2,3-triazoles (Chitotriazolan). The chitosan amines were converted to azide and then reacted with terminal alkynes in the presence of Cu (II) catalyst and sodium ascorbate. The derivatives were characterized by FT-IR, 1H, and 2D NMR techniques as well as SEC-MALS to determine the molecular weight. Derivatives were tested against bacteria.
Results: We have synthesized chitotriazolan products by two pathways, with and without protection of hydroxy groups with TBDMS (C-3 and C-6 position). In the current work we were successful in obtaining full conversion to obtain the first water soluble chitotriazolan’s. Eleven chitotriazolan’s were synthesized through two routes and five of the structures had good water solubility. These structures were characterized by 1H-NMR and IR spectroscopy. The antibacterial activity was evaluated against S. aureus and E. coli at pH 7.2.
Conclusion: Chitotriazolan’s synthesized via copper catalyzed azide-alkyne cycloaddition reaction and were investigated the antibacterial activity. The degree of azidation to 1,2,3-triazole was more than 90%, as confirmed by 1H-NMR. The quaternized cationic chitotriazolan’s had good antibacterial activity whereas the anionic chitotriazolan’s were inactive.
