Bazin H G, Capila I, Linhardt R J
Division of Medicinal and Natural Products Chemistry, University of Iowa, Iowa City 52242, USA.
Carbohydr Res. 1998 Jun;309(2):135-44. doi: 10.1016/s0008-6215(98)00118-9.
Sixteen delta 4-uronate monosaccharides were chemically synthesized. Their carboxy group was protected as a methyl or benzyl ester, the anomeric hydroxyl group as a benzyl glycoside and the 2 and 3 hydroxyl groups were protected with different substitution patterns as both ester and ether derivatives. Disaccharides containing delta 4-uronates were prepared from heparin layses. Their carboxy group was unprotected or protected as a benzyl ester and the two hydroxyls in the uronate moiety were free, as O-sulfo derivates or acylated. The conformation of these unsaturated uronate monosaccharide and disaccharide residues was studied using 1H NMR by examining interproton vicinal coupling constants. The delta 4-uronate residue adopted either the 2H1 or the 1H2 conformations. The equilibrium between these two conformers was shown to be controlled by substitution pattern.
十六种δ4-糖醛酸单糖被化学合成。它们的羧基被保护为甲酯或苄酯，异头羟基被保护为苄基糖苷，2位和3位羟基以不同的取代模式同时被保护为酯和醚衍生物。含有δ4-糖醛酸的二糖由肝素裂解酶制备。它们的羧基未被保护或被保护为苄酯，糖醛酸部分的两个羟基是游离的、为O-磺基衍生物或被酰化。通过检查质子间邻位偶合常数，利用1H NMR研究了这些不饱和糖醛酸单糖和二糖残基的构象。δ4-糖醛酸残基采用2H1或1H2构象。这两种构象体之间的平衡显示受取代模式控制。
