Manger I D, Rademacher T W, Dwek R A
Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, U.K.
Biochemistry. 1992 Nov 10;31(44):10724-32. doi: 10.1021/bi00159a012.
Incubation of reducing sugars in ammonium bicarbonate was found to be a simple procedure for the formation of beta-D-glycosylamines of purified complex oligosaccharides in 70-80% yield. These provide valuable intermediates for the synthesis of a wide range of oligosaccharide probes and derivatives by acylation of the 1-amino function. The 1-amino function showed different rates of reactivity with different reagents. In general, interactions with large ring systems such as the fluorophores dansyl chloride and carboxyfluorescein gave 10-20% yields of products, which consisted of mixtures of both anomeric forms, whereas smaller acylating reagents gave near-quantitative yields of the desired beta-D-derivatives. Steric effects may explain differences in reactivity. N-Chloroacetamido derivatives could be obtained in high yield with retention of the beta-anomeric configuration. Subsequent ammonolysis of the chloroacetamido function afforded the corresponding N-glycyl beta-derivatives. The linker thereby introduced retains the amino function, possesses the useful properties of fixed anomeric configuration, improved stability, and uniform reactivity with a variety of reagents, and is structurally analogous to an asparagine side chain. The potential therefore exists for the generation of oligosaccharide derivatives tailored for different applications.
研究发现，在碳酸氢铵中孵育还原糖是一种简单的方法，可用于以70-80%的产率形成纯化复合寡糖的β-D-糖基胺。这些为通过1-氨基官能团的酰化反应合成多种寡糖探针和衍生物提供了有价值的中间体。1-氨基官能团与不同试剂的反应速率不同。一般来说，与大环状体系（如荧光团丹磺酰氯和羧基荧光素）相互作用得到的产物产率为10-20%，产物由两种异头物形式的混合物组成，而较小的酰化试剂则能得到接近定量产率的所需β-D-衍生物。空间效应可能解释了反应性的差异。可以高产率获得保留β-异头构型的N-氯乙酰氨基衍生物。氯乙酰氨基官能团随后的氨解反应得到相应的N-甘氨酰β-衍生物。由此引入的连接子保留了氨基官能团，具有固定异头构型、提高稳定性以及与多种试剂具有均匀反应性的有用特性，并且在结构上类似于天冬酰胺侧链。因此，存在生成针对不同应用量身定制的寡糖衍生物的潜力。
