title: Nonnatural branched polysaccharides: synthesis and properties of chitin and chitosan having disaccharide maltose branches.
abstract: Synthesis and properties of chitin and chitosan derivatives having beta-maltoside branches at C-6 have been studied. Chitosan was first transformed into an organosoluble acceptor having a reactive group only at C-6, 3-O-acetyl-2-N-phthaloyl-6-O-trimethylsilylchitosan. Glycosylation with an ortho ester from d-maltose was performed successfully at room temperature in dichloromethane in the presence of trimethylsilyl trifluoromethanesulfonate as the catalyst. The degree of substitution could be controlled by the reaction conditions and was up to 0.56. Full deprotection gave chitosan with maltoside branches, and the subsequent N-acetylation resulted in the formation of the corresponding chitin derivative. The introduced disaccharide unit improved hydrophilic properties considerably compared to monosaccharide units as confirmed by high solubility in water and moisture absorption and retention ability. The enzymatic degradability and antimicrobial activity were moderate probably because of the bulky nature of the branches.
authors.affiliation: Department of Applied Chemistry, Faculty of Engineering, Seikei University, Musashino-shi, Tokyo 180-8633, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Kurita
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Akao
authors.forename: Jin
authors.initials: J
authors.lastname: Yang
authors.forename: Manabu
authors.initials: M
authors.lastname: Shimojoh
mesh_terms: D001673:Biodegradation, Environmental; D002236:Carbohydrate Conformation; D002686:Chitin / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000378:metabolism; D048271:Chitosan; D004187:Disaccharides / Q000737:chemistry; D006031:Glycosylation; D008320:Maltose / Q000737:chemistry; D009113:Muramidase / Q000378:metabolism; D011134:Polysaccharides / Q000138:chemical synthesis / Q000378:metabolism; D012995:Solubility
chemical_list: D004187:Disaccharides; D011134:Polysaccharides; D002686:Chitin; D008320:Maltose; D048271:Chitosan; D009113:Muramidase