title: Regioselective silylation of N-phthaloylchitosan with TBDMS and TBDPS groups.
abstract: N-Phthaloylchitosan represents a key intermediate for the regioselective modification of chitosan in organic media. Chemoselective protection of primary alcohols on N-phthaloylchitosan was achieved with tert-butyldimethylsilyl (TBDMS) and tert-butyldiphenylsilyl (TBDPS) groups in imidazole/DMF and DMAP/pyridine. Influence of experimental conditions such as solvent, choice of base, stoichiometry, temperature, and time of reaction was studied regarding the degree of substitution (ds) of silyl groups. TBDMS groups allow higher ds than TBDPS groups. Higher reaction temperatures in different conditions led to lower ds and incomplete substitution. However, regioselective silylation of N-phthaloylchitosan was realized with ds up to 0.92 at room temperature. Silylated derivatives were characterized by elemental analysis, IR, and CP/MAS 13C NMR spectroscopies.
authors.affiliation: Département de biologie, chimie et géographie, Université du Québec à Rimouski, 300, allée des Ursulines, Rimouski, Québec, Canada, G5L 3A1.
authors.forename: Alain
authors.initials: A
authors.lastname: Binette
authors.forename: Jonathan
authors.initials: J
authors.lastname: Gagnon
mesh_terms: D000438:Alcohols / Q000737:chemistry; D002686:Chitin / Q000031:analogs & derivatives* / Q000737:chemistry; D048271:Chitosan / Q000737:chemistry*; D046911:Macromolecular Substances; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008956:Models, Chemical; D008968:Molecular Conformation; D012821:Silanes / Q000737:chemistry*; D012833:Siloxanes / Q000737:chemistry*; D012995:Solubility; D012997:Solvents / Q000737:chemistry; D013055:Spectrophotometry, Infrared; D013343:Styrenes / Q000737:chemistry*; D013696:Temperature
chemical_list: C506477:4-(tert-butyldimethylsiloxy)styrene; D000438:Alcohols; D046911:Macromolecular Substances; C483239:N-phthaloylchitosan; D012821:Silanes; D012833:Siloxanes; D012997:Solvents; D013343:Styrenes; C103256:tert-butyldimethylsilane; D002686:Chitin; D048271:Chitosan