SYNTHESES OF THE ANALOGUES AND THE KETOSIDE DERIVATIVES OF SIALIC ACID,KDO,AND KDN.

1. 采用氨基型Horner-Witting反应，合成了3-脱氧-d -甘露-2-辛糖酸（KDO）、3-脱氧-d -甘油-d -半乳糖-2-非纽糖酸（KDN）和5-乙酰氨基-3,5-二脱氧-d -甘油-d -半乳糖-2-非纽糖酸（n -乙酰神经氨酸，NANA）。在此基础上，还合成了3-脱氧-d -阿拉伯糖-2-庚糖醛酸和3-脱氧-d -葡萄糖-2-辛糖醛酸等乌糖醛酸类似物。该方法的优点是选择了镀液的氨基保护基团[如苯氧羰基（Cbz）和t-丁氧羰基（Boc）]。因此，我们可以选择所需的保护基团，对起始材料的羟基进行保护。利用稳定的Horner-Witting试剂的新方法将为大规模合成ulosonic酸衍生物提供一条途径。利用以上知识，我们还合成了5-epi-KDN衍生物，用于合成KDN和^<15>N -标记唾液酸（NANA）的C-5修饰类似物。

1. The biologically important terminal units of lipopolysaccharides, 3-deoxy-D-manno-2-octulosonic acid (KDO), 3-deoxy-D-glycero-D-galacto-2-nonulosonic acid (KDN), and 5-acetamido-3,5-dideoxy-D-glycero-D-galacto-2-nonulosonic acid (N-acetylneuraminic acid, NANA) were synthesized by the use of amino type Horner-Witting reaction. On the basis of above knowledge, ulosonic acid analogues such as 3-deoxy-D-arabino-2-heptulosonic acid and 3-deoxy-D-gluco-2-octulosonic acid were also synthesized. Merit of this method is to select the amino protecting group [such as benzyloxycarbonyl (Cbz) and t-butoxycarbonyl (Boc) ] of witting reagent. As a result, we can select the protecting group, which is needed, for the protection of hydroxyl group of starting materials. This newly developed methods by the use of stable Horner-Witting reagent will provide a route to large scale synthesis of ulosonic acid derivatives.2. By the use of the above knowleges, 5-epi-KDN derivative was also synthesized for synthesizing C-5 modified analogs of KDN and ^<15>N -labeled sialic acid (NANA).