1H-Nuclear magnetic resonance spectroscopy of reducing-residue anomeric protons of pertrifluoroacetylated carbohydrates
作者:Steven T. Summerfelt、Etienne J.-M. Selosse、Peter J. Reilly、Walter S. Trahanovsky
DOI:10.1016/0008-6215(90)80014-t
日期:1990.8
from the same carbohydrates when they were free or derivatized with other groups. Neither the location of anomeric proton peaks relative to each other nor the degree of spin-spin coupling between H-1 and H-2 varied greatly with type of derivatization. Spin-spin coupling, however, decreased for some beta-pyranose forms of xylobiose and the three trisaccharides. In all examples except some where H-2 was
八个单糖(L-阿拉伯糖苷,L-岩藻糖,D-半乳糖,D-葡萄糖,D-lyxose,D-甘露糖,L-鼠李糖和D-木糖),八个二糖(纤维二糖,龙胆二糖,异麦芽糖,乳糖,麦芽糖,用吡啶溶液中的N-甲基双-(三氟乙酰胺)衍生化了黑糖,槐糖和木糖以及三种三糖(异麦芽三糖,麦芽三糖和木三糖),形成三氟乙酰化衍生物。通过1H-nmr光谱法对它们进行分析,以确定光谱的特征和反应产物的分布。对应于还原残基异头质子的峰位于所有其他场的显着下场,并且当它们与其他基团游离或衍生时,通常来自相同碳水化合物的等价信号的场下限为0.4 ppm或更高。异头质子峰的相对位置和H-1和H-2之间的自旋-自旋偶联程度都不会因衍生化类型而有很大变化。但是,对于某些木糖和三种三糖的β-吡喃糖形式,自旋-自旋偶联降低。在所有实施例中,除了一些其中H-2相对于吡喃糖环赤道取向的实施例之外,通过三氟乙酰化提高或不改变α-吡喃糖的比例。