SYNTHESIS AND BIOCHEMISTRY OF ASCORBIC ACID ANALOGUES

抗坏血酸（维生素C）是人体健康的膳食必需品， 电子供体几种酶促作用，作为抗氧化剂， 并与宿主防御机制、内分泌功能和 视觉过程（透镜）。 生物化学最近重新引起人们的兴趣， 抗坏血酸的出现是因为人们认识到， 已知的是关于维生素所需的浓度， 这几个角色的最佳功能。 在酶的情况下， 反应，过程的最佳速率被定义为该浓度 使反应达到Vmax而没有毒性。 的一部分 程序来确定这些浓度，原位动力学测量 已经进行了某些维生素C相关的反应。 在 除了检查维生素C的功能作用，最近 有效转运机制的表征， 维生素C穿过细胞膜的重要性， 维生素对生物过程的影响 这些运输的动力学参数 机制也在确定中。 6-脱氧-6-卤代抗坏血酸转运抑制的动力学测定 酸类似物已经清楚地证明存在单独的 抗坏血酸和脱氢抗坏血酸的转运途径。 使用我们的路线6-芳氧基-抗坏血酸类似物，我们已经制备 放射性标记的官能化类似物， 与抗坏血酸转运蛋白的不可逆结合。 探讨 2-羟基对抗坏血酸活性的重要性，我们有 制备2-脱氧-抗坏血酸。 这种类似物将作为一个开始， 用于尝试制备未知2-脱氧-2-卤代 抗坏血酸，包括2-脱氧-2-氟-抗坏血酸，电子等排的 和等极性的、不可氧化的类似物。

Ascorbic acid (vitamin C), a dietary requirement for human health, is an electron donor several enzymatic actions, functions as an antioxidant, and is implicated in host defense mechanisms, endocrine function and the visual process (lens). Recent renewed interest in the biochemistry of ascorbic acid has been prompted by the realization that relatively little is known concerning the concentrations of the vitamin required for optimum functioning of these several roles. In the case of enzymatic reactions, optimal rate of a process is defined as that concentration that allows the reaction to reach Vmax without toxicity. As part of a program to determine these concentrations, in situ kinetic measurements have been carried out for certain vitamin C-linked reactions. In addition to examination of functional roles of vitamin C, recent characterization of efficient transport mechanisms that translocate vitamin C across cellular membranes has emphasized the importance of th vitamin to biological processes. Kinetic parameters of these transport mechanisms are also being determined. Kinetic measurements of transport inhibition of 6-deoxy-6-haloascorbic acid analogues have clearly demonstrated the presence of separate pathways for the translocation of ascorbic acid and dehydroascorbic acid. Using our route to 6-aryloxy-ascorbic acid analogues, we have prepared radiolabeled functionalized analogues having the potential for irreversible binding to the ascorbic acid transporter. To investigate the importance of the 2-hydroxyl group on ascorbic acid activity, we have prepared 2-deoxy-ascorbic acid. This analogue will be used as a starting material for the attempted preparation of the unknown 2-deoxy-2-halo ascorbic acids, including 2-deoxy-2-fluoro-ascorbic acid, an isosteric and isopolar, non oxidizable, analogue.