Nakabayashi S, Warren C D, Jeanloz R W
Department of Biological Chemistry, Harvard Medical School, Boston, Massachusetts.
Carbohydr Res. 1988 Mar 15;174:279-89. doi: 10.1016/0008-6215(88)85097-3.
The heptasaccharide O-alpha-D-mannopyranosyl-(1----6)-O-[alpha-D-mannopyranosyl-(1----3)]-O- alpha-D-mannopyranosyl-(1----6)-O-[alpha-D-mannopyranosyl-(1----3)]-O-be ta- D-mannopyranosyl-(1----4)-O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)- (1----4)-2-acetamido-2-deoxy-D-glucopyranose, isolated from the urine of swainsonine-intoxicated sheep, was peracetylated and was converted into the glycosyl azide by three alternative procedures, the most successful of which was formation of peracetyl oxazoline by treatment with trimethylsilyl trifluoromethanesulfonate, followed by treatment with trimethylsilyl azide. Reduction of the glycosyl azide in the presence of Lindlar catalyst gave the glycosylamine derivative, which was coupled with 1-benzyl N-fluoren-9-ylmethoxycarbonyl-L-aspartate to yield a protected glycosylasparagine. The benzyl ester group was easily removed by hydrogenolysis to form an intermediate suitable for glycopeptide synthesis.
从苦马豆素中毒绵羊尿液中分离得到的七糖O-α-D-吡喃甘露糖基-(1→6)-O-[α-D-吡喃甘露糖基-(1→3)]-O-α-D-吡喃甘露糖基-(1→6)-O-[α-D-吡喃甘露糖基-(1→3)]-O-β-D-吡喃甘露糖基-(1→4)-O-(2-乙酰氨基-2-脱氧-β-D-吡喃葡萄糖基)-(1→4)-2-乙酰氨基-2-脱氧-D-葡萄糖进行了全乙酰化，并通过三种不同方法将其转化为糖基叠氮化物，其中最成功的方法是用三甲基甲硅烷基三氟甲磺酸酯处理形成全乙酰化恶唑啉，随后用三甲基甲硅烷基叠氮化物处理。在林德拉催化剂存在下还原糖基叠氮化物得到糖基胺衍生物，该衍生物与1-苄基N-芴甲氧羰基-L-天冬氨酸偶联生成保护的糖基天冬酰胺。苄酯基团通过氢解容易除去，形成适合糖肽合成的中间体。
