碳环的

Over the past four decades, many dearomatization reactions have developed and applied for synthesis of alicyclic compounds con-taining six–membered carboncyclic moieties.

芳香族化合物稳定、易得，通过芳香族化合物的脱芳构化反应，制备官能化的脂肪六元碳环化合物，早以引起人们的广泛兴趣。

Like many of the molecular species that have been detected inthe interstellar medium, the singlet carbene cyclopropenylidene(C3H2), has been presumed too unstable to isolate in the laboratory.

一个名为cyclopropenylidene的三角形碳环分子过去只是在星际空间被探测到，现在一个研究小组在地球上的实验室中制造出了稳定的这种分子。

The results indicated that the ionization potential I(subscript p and band gap E(subscript g of the copolymers were reduced with an increase of the length of the alkyl chain.

结果表明，随噻吩环3位取代烷基碳链的增长，聚合物电离能I

To further explore tillage practices for improving soil structure, the effect of different tillage practices on the structure and organic carbon of tilth soils were investigated using routine method (Wet-sieving, Potassium dichromate volumetry and Core-cutting sampling).

为了寻求能够提高土壤结构稳定性的耕作模式，在陇中黄土高原半干旱区连续7年的定位试验研究基础上，采用常规分析方法(湿筛法、重铬酸钾容量法、环刀法)，研究了不同耕作方式对耕层土壤结构性能及有机碳含量的影响。

Their diasteroisomers were achieved because the group of alkoxy assaulted C_1 of 2-deoxyribofuranosyl chloride from different directions.

因烷氧基可从呋喃脱氧糖环的不同方向进攻1-位碳原子，因而所得到的烷基呋喃脱氧戊糖苷是一对非对映异构体。

The difference of chemical shifts of heterocyclic hydrogen and carbon resonance signals was produced by the inductive, conjugative, magnetic anisotropy, and stereo effects of substituents for different tropane compounds.

取代基的诱导效应、共轭效应、磁各向异性效应和立体效应对莨菪烷化合物杂环上氢核和碳核的化学位移有较大的影响。

Luzoniana collected from the South China sea were studied. A compound, isolated from the soft coral, was found to be a bicyclic diterpene alcohol with a rearranged dolabellane skeleton.

应用波谱和X-射线单晶衍射分析等方法确定Ⅰ为具有变形dolabellane型碳架的双环二萜醇：(3 E，5 S，7 E，11 S，12 S，14 Z)-11-甲基-15-降dolabella-3，7，14-三烯-5-醇(图1)。

Then the protected D-mannitol, mixed with lead tetraacetate, hippuric and acetic anhydride, were refluxed in THF for 18 h in a one-pot two step reaction to afford a chiral precursor-2-phenyl-4-[-2,3-O-]-propylidene-5(4H)-oxazolones.

产物与四乙酸铅、马尿酸、乙酐于THF中回流18 h完成一釜二步反应，纯化后得到含有手性碳原子的环丙烷氨基酸前体-2 苯基-4-[-2，3-O-]丙叉？

Three types of dyes derived from crown ether benzotellurazole (including telluracarbocyanine, polymethine styryl dye and merocyanine dye) are formed by the methods analogous to non-crown ether dyes.

本文系统研究了冠醚苯并碲唑的各种合成方法，探讨了杂环的季铵化反应，并进一步制备了对称冠醚碲碳菁及冠醚苯并碲唑衍生的多甲川苯乙烯菁、部花青染料。

It is consistent with our assignments that the first peak was mainly the excitations between oxygen and carbon rings.

这与TCDD光谱图中第一个峰是氧和碳环之间的电子跃迁相一致。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。