Microwave effect for glycosylation promoted by solid super acid in supercritical carbon dioxide.
The effects of microwave irradiation (2.45 GHz, 200 W) on glycosylation promoted by a solid super acid in supercritical carbon dioxide was investigated with particular attention paid to the structure of the acceptor substrate. Because of the symmetrical structure and high diffusive property of supercritical carbon dioxide, microwave irradiation did not alter the temperature of the reaction solution, but enhanced reaction yield when aliphatic acceptors are employed. Interestingly, the use of a phenolic acceptor under the same reaction conditions did not show these promoting effects due to microwave irradiation. In the case of aliphatic diol acceptors, the yield seemed to be dependent on the symmetrical properties of the acceptors. The results suggest that microwave irradiation do not affect the reactivity of the donor nor promoter independently. We conclude that the effect of acceptor structure on glycosylation yield is due to electric delocalization of hydroxyl group and dielectrically symmetric structure of whole molecule.
Hinou
Hiroshi
H
Division of Advanced Chemical Biology, Graduate School of Life Science, Hokkaido University, N21, W11, Sapporo 001-0021, Japan.
Saito
Naohiro
N
Division of Advanced Chemical Biology, Graduate School of Life Science, Hokkaido University, N21, W11, Sapporo 001-0021, Japan.
Ogawa
Masato
M
Department of Technical Engineering, Faculty of Science, Hokkaido University, N10, W8, Sapporo 060-0021, Japan.
Maeda
Takahiko
T
Division of Advanced Chemical Biology, Graduate School of Life Science, Hokkaido University, N21, W11, Sapporo 001-0021, Japan.
Nishimura
Shin-Ichiro
SI
Division of Advanced Chemical Biology, Graduate School of Life Science, Hokkaido University, N21, W11, Sapporo 001-0021, Japan.
D000143:Acids / Q000737:chemistry*; D002245:Carbon Dioxide / Q000737:chemistry*; D006031:Glycosylation / Q000528:radiation effects; D017665:Hydroxyl Radical / Q000737:chemistry; D008872:Microwaves
D000143:Acids; D002245:Carbon Dioxide; D017665:Hydroxyl Radical