With a view to facilitating prediction of the exocyclic bond to the pyranoside ring in higher carbon sugars, a model is advanced that relates the relative configuration of the three stereogenic centers comprised of the branchpoint and of the two flanking centers (C4–C5–C6 in aldoheptoses and higher and C5–C6–C7 in sialic and ulosonic acids) to that of the simple ring-opened pentoses. Assignment of a given stereotriad as arabino, lxyo, ribo, or xylo by inspection of the Fischer projection formulas permits prediction of conformation of the exocyclic bond by comparison with the known solution (= crystal in all cases) conformations of the simple pentitols. More remote stereogenic centers in the side chain, as in the 8-position of N-acetylneuraminic acid, have little impact on the conformation of the exocyclic bond. On the basis of this model the conformation of the exocyclic bond in ring I of 6′-homologated 4,5-disubstituted 2-deoxystreptamine class aminoglycoside antibiotics was predicted and was borne out by NMR analysis of newly synthesized derivatives in D₂O at pD5. The antiribosomal and antibacterial activity of these derivatives is briefly presented and discussed in terms of preorganization of the side chain for binding to the ribosomal decoding A site. It is anticipated that this predictive analysis will also find use in the prediction of the conformation of the exocyclic bonds in other 2-(1-hydroxyalkyl)-3-hydroxytetrahydropyrans and tetrahydrofurans.

中文翻译：

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高碳糖侧链构象的预测分析：应用于与细菌核糖体解码 A 位点结合的氨基糖苷环 1 侧链的预组织。

为了促进高碳糖中吡喃糖苷环外环键的预测，提出了一个模型，该模型将由分支点和两个侧翼中心（C4-C5-C6）组成的三个立体中心的相对构型联系起来。庚糖和更高的醛糖以及唾液酸和乌洛糖酸中的 C5-C6-C7）与简单的开环戊糖。通过检查费歇尔投影公式将给定立体三联体指定为阿拉伯、lxyo、核糖或xylo，允许通过与简单戊醇的已知溶液（=在所有情况下为晶体）构象进行比较来预测环外键的构象。侧链中更远的立体中心，如N-乙酰神经氨酸的 8 位，对环外键的构象影响很小。_{在此模型的基础上，预测了6'-同源4,5-二取代2-脱氧链霉胺类氨基糖苷类抗生素环I中环外键的构象，并通过新合成衍生物在D 2} O中pD5的NMR分析得到证实。。简要介绍并讨论了这些衍生物的抗核糖体和抗菌活性，并根据与核糖体解码 A 位点结合的侧链的预组织进行了讨论。预计该预测分析还将用于预测其他2-(1-羟烷基)-3-羟基四氢吡喃和四氢呋喃中环外键的构象。