Preparation of C-6 substituted chitin derivatives under homogeneous conditions.
Tosylation of chitin under homogeneous conditions was achieved by the reaction of tosyl chloride with chitin in a DMAc/LiCl solvent system. The resultant tosyl-chitin was fully N-acetylated with acetic anhydride in methanol. The fully acetylated tosyl-chitin was subsequently reacted with the sodium salts of ethyl p-hydroxybenzoate, diethyl malonate, and diethyl phosphite in DMAc to give the corresponding chitin derivatives of 6-O-ethyl benzoate-chitin, 6-deoxy-diethyl malonate-chitin, and 6-(deoxydiethyl) phosphite-chitin, respectively. Subsequent hydrolysis of the chitin-ester derivatives with tert-butoxide in dimethyl sulfoxide (DMSO) generated 6-O-carboxyphenyl-chitin and 6-(deoxydicarboxy)methyl-chitin. The structures of the chitin derivatives were assessed by FT-IR, (13)C NMR, and (31)P NMR, while the degree of substitution of the S(N)2 reaction was estimated by elemental analysis. All the chitin derivatives were found to be soluble or swellable in water, DMAc, or DMSO.
Zou
Yuquan
Y
Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543.
Khor
Eugene
E
D002240:Carbohydrate Sequence; D002686:Chitin / Q000031:analogs & derivatives* / Q000138:chemical synthesis*; D008969:Molecular Sequence Data; D014105:Tosyl Compounds / Q000138:chemical synthesis
D014105:Tosyl Compounds; D002686:Chitin