N.M.R.-spectral studies of 2-linked glycosides: 2-O-glycosylation shifts of 2-O-glycosylated α- and β-l-arabinopyranosides
作者:Kenji Mizutani、Akiyo Hayashi、Ryoji Kasai、Osamu Tanaka、Naoko Yoshida、Terumi Nakajima
DOI:10.1016/0008-6215(84)85376-8
日期:1984.3
observed for the 2- O -glycosylated α- l -arabinopyranoside moiety, indicating an increase in the contribution of the 1 C 4 conformation of the glycosylated α- l -arabinopyranoside in these cases. On the other hand, no remarkable variation in the signals of C-3, -4, and -5, or in the 3 J H1,H2 and 1 J C1,H1 values, was found for 2- O -α- l -rhamnosylation, except for 4-epihederagenin-3-yl 2- O -α- l -rhamnopyranosyl-α-
摘要有时观察到2- O-β-d-glycopyranosyl(或-β-d -xylopyranosyl)的C-1(异头碳原子)和C-2(糖基氧基化碳原子)信号的异常糖基化位移值-β-d-吡喃葡萄糖苷,而在这些情况下未观察到其他糖碳信号的显着位移。由于2-O-糖基和1-O-糖苷基(或-糖)基团之间强烈的空间相互作用,这可以用糖基键的方向变化来解释。合成了各种2-O-糖基化的α-和β-1-阿拉伯吡喃糖苷。在α-1-α-吡喃果糖苷的情况下,2-O-β-d-葡糖基化,-β-d-木糖基化和-α-1-α-阿拉伯糖基化的过程导致了C-3的意想不到的高场移动,- 4和-5信号,以及C-1和-2共振的位移。此外,还观察到2-O-糖基化的α-1-α-吡喃吡喃糖苷部分的3 J H1,H2和1 J C1,H1的值发生了显着变化,表明其1 C 4构象的贡献增加。在这些情况下,糖基化的α-1-阿拉伯吡喃糖苷。另一方面