MODIFIED NUCLEOSIDE STRUCTURE FUNCTION RELATIONS TRNA

两种细胞壁聚合物--阿拉伯半乳聚糖和阿拉伯半乳糖的生物合成 脂阿拉伯甘露聚糖，将用无细胞制剂进行研究 耻垢分枝杆菌和结核分枝杆菌H37Ra。在现在 该项目的阶段，正在使用化学合成来获得 戊糖D-阿拉伯糖的核苷二磷酸衍生物。这个 目的是测试这些衍生物作为D-阿拉伯糖的主要供体 生物合成过程中的残留物。首选的合成材料 该程序涉及D-阿拉伯糖的糖苷化为甲基 A-D-阿拉伯呋喃糖苷，将糖苷苯甲酰化为 2，3，5-三苯甲酸酯和将苯甲酸酯转化为受保护的 糖基氯和/或溴化物。然后，糖基卤化物将被 用尿苷二磷酸盐的四丁基铵盐和 鸟苷二磷酸d-阿拉伯呋喃葡萄糖。或者， 四丁基二苄基磷酸铵可与 受保护的阿拉伯糖氯或溴，且产品不受保护 得到D-阿拉伯呋喃1-磷酸。1-磷酸的反应 与二磷酸核苷的磷形态磷酸盐 利息应给出相应的核苷二磷酸 阿拉伯氟尿嘧啶。由于市场上所有或几乎所有的中间体 建议的合成和两个最终产品已经被描述。 在文献中，可以通过检查高值来监视操作 获得的每种化合物的1H核磁共振谱的分辨率。为 最终产物~(13)C和~(31)P谱也可能有用。一旦 用普通试剂建立了合成的可靠性， 将进行放射性样品的制备， 1-[14C]-D-阿拉伯糖作为标记的起始原料。

The biosynthesis of two cell-wall polymers, arabinogalactan and lipoarabinomannan, is to be studied with cell-free preparations of Mycobacterium smegmatis and M. Tuberculosis H37Ra. In the present phase of the project, chemical synthesis is being used to obtain nucleoside diphosphate derivatives of the pentose D-arabinose. The object is to test these derivatives as primary donors of D-arabinose residues in the biosynthetic process. The preferred synthetic procedure involves the glycosidation of D-arabinose to methyl a-D-arabinofuranoside, benzoylation of the glycoside to the 2,3,5-tribenzoate, and conversion of the benzoate into the protected glycosyl chloride and/or bromide. The glycosyl halides will then be treated with the tetrabutylammonium salts of uridine diphospate and guanosine diphosphate d-arabinofuranoses. Alternatively, tetrabutylammonium dibenzyl phosphate may be reacted with the protected arabinosyl chloride or bromide, and the product deprotected to give D-arabinofuranose 1-phosphate. Reaction of the 1-phosphate with the phosphormorpholidates of the nucleoside diphosphate of interest should give the corresponding nucleoside diphosphate arabinofuranoses. Since all or nearly all of the intermediates in the proposed syntheses, and two of the final products, have been described in the literature, operations can be monitored by examining the high resolution 1H NMR spectrum of each compound as it is obtained. For the final products 13C and 31P spectra may also be useful. Once the reliability of the syntheses is established with ordinary reagents, the preparation of radioactive samples will be undertaken, with 1-[14C]-D-arabinose as the labeled starting material.