杂环原子

Generally speaking, the reaction types involvingα-oxoketene--acetals mainly include the regioselective addition-aromatization with organometallic reagents, conjugate addition-cyclization with nitrogen nucleophilicspecies, nucleophilic reactions ofα-carbon, acting as odorless dithiol equivalentsin thioacetalization, Michael additions and [5+1] annulation, as well as the synthetic applications based on the above reactions.

一般来说，基于α-羰基二硫缩烯酮化学的反应主要为：与金属有机试剂的选择性加成反应，与氮亲核体的共轭加成反应，α-碳原子的亲核性及相关反应，烷硫基作为硫醇的替代试剂的应用，α-羰基二硫缩烯酮在碳环、杂环化合物合成中的应用等。

A large number of bond-type complexes, as long as the hydrogen of the molecules covalently coupled to the molecular approach in an electronegative atom up, that constitutes a hydrogen bond, there are intramolecular hydrogen bonds and intermolecular hydrogen bonds of the points, will affect the formation of complex reaction carried out, such as in solution adding dioxa cyclohexane, or tetrahydrofuran, will reduce the alkylation reaction rate.

氢键型络合物为数众多，只要含氢的分子以共价键方式耦合到分子中一个电负性原子上去，即构成氢键，有分子内氢键和分子间氢键之分，络合物的形成将会影响反应的进行，如在溶液中加入二氧杂环己烷或四氢呋喃，都会降低烷基化反应速率。

The luminescent property of these materials was relative to the twisted angle between two benzene rings of the bridged biphenyl. The crystal structures of a series of seven-member heterocycle bridged biphenyls were determined by X-ray diffraction.

利用X射线单晶衍射仪确定了系列功能的七元杂环桥联联苯化合物的晶体结构，比较了桥联原子，6，6位取代基及分子间弱氢键对这类桥联联苯扭曲构象的影响。

It is the hotspot research in the field of synthesis of functional macromolecule materials at present.

利用咪唑啉含有两个氮原子的五元杂环化合物特殊结构，在其合成过程中对官能团"枝接"其他功能基团，使之成为具有特殊功能的化学品，是目前国际上合成功能高分子材料研究的热点。

Purine: Any of a class of heterocyclic compounds with a two-ring structure composed of carbon and nitrogen atoms.

嘌呤：嘌呤是对由碳、氮原子组成的双环结构的杂环化合物的统称。

Purine: Any of a class of heterocyclic compounds with a two-ring structure composed of carbon and nitrogen atom s.

嘌呤：嘌呤是对由碳、氮原子组成的双环结构的杂环化合物的统称。

Purine: Any of a class of heterocyclic compound s with a two-ring structure composed of carbon and nitrogen atoms.

嘌呤：嘌呤是对由碳、氮原子组成的双环结构的杂环化合物的统称。

Purine: Any of a class of heterocyclic compounds with a two-ring structure compose d of carbon and nitrogen atoms.

嘌呤：嘌呤是对由碳、氮原子组成的双环结构的杂环化合物的统称。

Pyrimidine: Any of a class of heterocyclic compounds with a ring structure of four carbon and two nitrogen atoms .

嘧啶：具有环状结构(由4个碳原子和2个氮原子组成)的一类杂环化合物。

Pyrimidine: Any of a class of heterocyclic compound s with a ring structure of four carbon and two nitrogen atoms.

嘧啶：具有环状结构(由4个碳原子和2个氮原子组成)的一类杂环化合物。

The labia have now been sutured together almost completely.The drains and the Foley catheter come out at the top.

此刻阴唇已经几乎完全的缝在一起了，排除多余淤血体液的管子和Foley导管从顶端冒出来。

To get the business done, I suggest we split the difference in price.

为了做成这笔生意，我建议我们在价格上大家各让一半。