13319-32-9Relevant articles and documents
Catalytic Depolymerization of Chitin with Retention of N-Acetyl Group
Yabushita, Mizuho,Kobayashi, Hirokazu,Kuroki, Kyoichi,Ito, Shogo,Fukuoka, Atsushi
, p. 3760 - 3763 (2015/12/08)
Chitin, a polymer of N-acetylglucosamine units with β-1,4-glycosidic linkages, is the most abundant marine biomass. Chitin monomers containing N-acetyl groups are useful precursors to various fine chemicals and medicines. However, the selective conversion of robust chitin to N-acetylated monomers currently requires a large excess of acid or a long reaction time, which limits its application. We demonstrate a fast catalytic transformation of chitin to monomers with retention of N-acetyl groups by combining mechanochemistry and homogeneous catalysis. Mechanical-force-assisted depolymerization of chitin with a catalytic amount of H2SO4 gave soluble short-chain oligomers. Subsequent hydrolysis of the ball-milled sample provided N-acetylglucosamine in 53 % yield, and methanolysis afforded 1-O-methyl-N-acetylglucosamine in yields of up to 70 %. Our process can greatly reduce the use of acid compared to the conventional process.
Kinetics of hydrolysis of chitin/chitosan oligomers in concentrated hydrochloric acid
Einbu, Aslak,Grasdalen, Hans,Varum, Kjell M.
, p. 1055 - 1062 (2008/02/03)
The kinetics of hydrolysis in concentrated hydrochloric acid (12.07 M) of the fully N-acetylated chitin tetramer (GlcNAc4) and the fully N-deacetylated chitosan tetramer (GlcN4) were followed by determining the amounts of the lower DP oligomers as a function of time. A theoretical model was developed to simulate the kinetics of hydrolysis of the three different glycosidic linkages in the tetramers. The model uses two different rate constants for the hydrolysis of the glycosidic bonds in the oligomers, assuming that the glycosidic bond next to one of the end residues are hydrolysed faster than the two other glycosidic linkages. The two rate constants were estimated by fitting model data to experimental results. The results show that the hydrolysis of the tetramers is a nonrandom process as the glycosidic bonds next to one of the end residues are hydrolysed 2.5 and 2.0 times faster as compared to the other glycosidic linkages in the fully N-acetylated and fully N-deacetylated tetramer, respectively. From previous results on other oligomers and the reaction mechanism, it is likely that the glycosidic bond that is hydrolysed fastest is the one next to the nonreducing end. The absolute values for the rate constants for the hydrolysis of the glycosidic linkages in GlcNAc4 were found to be 50 times higher as compared to the glycosidic linkages in GlcN4, due to the catalytic role of the N-acetyl group and the presence of the positively charged amino-group on the N-deacetylated sugar residue.
Ring-opening glycosylation of a chitobiose oxazoline catalyzed by a non-chitinolytic mutant of chitinase
Sakamoto, Junji,Watanabe, Takeshi,Ariga, Yumiko,Kobayashi, Shiro
, p. 1180 - 1181 (2007/10/03)
Ring-opening glycosylation of a chitobiose oxazoline was exclusively achieved by catalysis of a mutated chitinase that is only active for the glycosylation and not for chitinolysis.