New prospects for the synthesis of N-alkyl phosphonate/phosphonic acid-bearing oligo-chitosanElectronic supplementary information (ESI) available. See DOI: 10.1039/c4ra02501f

• Main Authors: Illy, N, Couture, G, Auvergne, R, Caillol, S, David, G, Boutevin, B
• Format: Journal Article
• Language: English
• Published: 09.06.2014
• ISSN: 2046-2069
• DOI: 10.1039/c4ra02501f

N -phosphonomethylation reactions of oligo-chitosan were performed according to Moedritzer and Kabachnik-Fields conditions. The different Moedritzer reaction conditions used did not allow the phosphonomethylation. On the contrary, the Kabachnik-Fields reactions led to oligo-chitosan methyl phosphonated derivatives. In addition, novel dialkyl phosphoryl oligo-chitosan was synthesized in water at room temperature via epoxy-amine reactions of oligo-chitosan with dialkyl (3-(oxiran-2-ylmethoxy)propyl) phosphonates. This simple and efficient synthetic method provides a new approach for the preparation of phosphonated oligo-chitosan derivatives. Then, the hydrolysis of the phosphonated compounds to generate the phosphonic acid moieties was investigated. The mildest conditions were determined in order to avoid the chitosan backbone degradation. All the products were characterized by 1 H and 31 P NMR analyses. Water-soluble oligo-chitosan were functionalized with N -alkyl phosphonate/phosphonic acid groups via Kabachnik-Fields and epoxy-amine reactions.