期刊
CARBOHYDRATE RESEARCH
卷 339, 期 7, 页码 1353-1360出版社
ELSEVIER SCI LTD
DOI: 10.1016/j.carres.2004.02.016
关键词
4-nitrophenyl beta-D-xylopyranoside acetates; lipase PS-30; regioselectivity; acetyl migration kinetics; acetylesterase assay
Di-O-acetates and mono-O-acetates of 4-nitrophenyl beta-D-xylopyranoside were prepared by use of lipase PS-30. Polarity of organic solvents and reaction time affected the regioselectivity of the di-O-acetylation as well as the yields of monoacetates. The kinetics of acetyl groups migration in these derivatives was studied in aqueous media using HPLC. Migration of the acetyl group strongly depended on pH. The highest rate of acetyl migration was observed from O-2 to O-3 in both 2,4-di-O-acetate and 2-O-acetate. On the contrary, acetyl exchange between O-3 and O-4 in both directions was slower than between O-2 and O-3. The 2,3-di-O-acetate and 4-O-acetate showed to be the most stable towards acetyl migration. The 3,4-di-O-acetate and 4-O-acetate were dominant in the corresponding equilibration mixtures. (C) 2004 Elsevier Ltd. All rights reserved.
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