Syntheses of Novel Chitosan Derivatives Soluble in Organic Solvents by Regioselective Chemical Modifications

Abstract

Regioselective chemical modifications of chitosan were successfully carried out in homogeneous solution under mild condition using phthalimido chitosan as a key starting material. Discrimination between the primary and secondary hydroxyl groups were also examined by O-tritylation or O-tosylation. As anticipated, the new chitosan derivatives exhibited a much improved solubility in common organic solvents.

A Biopolymer Chitosan and Its Derivatives as Promising Antimicrobial Agents against Plant Pathogens and Their Applications in Crop Protection

“…The preparation of O,O-didecanoyl chitosan was also reported through a protected N-phthaloyl chitosan as intermediate [176]. However, this method needs several steps for the protection and deprotection of the Nphthaloyl groups [177]. Some N-carboxyacyl chitosans were also prepared by reaction of chitosan with intramolecular carboxylic anhydrides including maleic, glutaric, phthalic, and succinic [115,165,178].…”

Synthesis and adsorption properties for metal ions of mesocyclic diamine-grafted chitosan-crown ether

“…Since chitosan has both hydroxyl and amino groups that can react with epoxide in nucleophilic substitution and opening of the epoxide ring, the most favorable nucleophilic center of chitosan is the amino group. 9,10 In order that the graft copolymerization of CTS can occur at the C6 position, the C2 amino group in chitosan was protected from the reaction of benzaldehyde and chitosan to form Schiff base chitosan. The basic reaction scheme is described in Figure 1.…”

A conjugate from a laminin-related peptide, Tyr-Ile-Gly-Ser-Arg, and chitosan: efficient and regioselective conjugation and significant inhibitory activity against experimental cancer metastasis

“…DCC-mediated coupling of peptide 1 with chitosan suspended in DMA failed to yield the peptide-chitosan conjugate, due to the heterogeneous conditions used. However, regioselective introduction of the peptide at the amino function of chitosan has been accomplished using an organosoluble chitosan derivative, 6-O-trityl (Trt)-chitosan, 17 which has a protective group at the reactive C-6 hydroxy function. 6-O-Trtchitosan was prepared as reported previously; 17 carbodiimide hydrochloride (WSCI, 1.2 equiv.…”