Synthetic applications of glucose isomerase: isomerisation of C-5-modified (2R,3R,4R)-configured hexoses into the corresponding 2-ketoses
摘要:
Immobilised glucose isomerase (EC 5.3.1.5) accepted various (2R,3R,4R)-configured hexoses such as 5-deoxy-D-ribo-hexose, 5-azido-5-deoxy-D-allose, as well as the corresponding epimer at C-5, 5-azido-5-deoxy-L-talose, as substrates. From the resulting azidodeoxyketoses, 5-azido-5-deoxy-D-psico- and -L-tagatopyranose, the powerful D-galactosidase inhibitors 2,5-dideoxy-2,5-imino-D-galactital and -D-altritol were obtained in one additional step. (C) 1999 Elsevier Science Ltd. All rights reserved.
据报道,在结构上与calystegines的糖苷酶抑制剂家族有关的多羟基化6-氧杂-正-托烷烷糖模拟物的制备。合成策略涉及5-脱氧-5-脲基-1-ID糖前体的呋喃糖→哌啶重排,然后涉及伯羟基的分子内糖基化。所得6-氧杂-(+)-calystegine B 2类似物在C-3处的构型反转允许进入难以捉摸的3 - epi -6-氧杂-(+)-calystegine B 2骨架。然而,观察到正二十烷的酸催化的开环,可以通过小心地中和反应混合物来避免。抑制结果表明(+)-calystegine B 2 衍生物和相应的C-3差向异构体可以分别看作是糖模拟物和半拟模拟物,指向该生物碱家族的1-氮杂糖作用方式。