苯环

The purpose of this paper is to synthesize some phosphonium salts with PPh3 and some chiral quaternary ammonium salts with L-Valine. And we also use L-Valine and L-Phe-OMe to synthesize a new type catalyst —2,5-diketopiperazine , the simplest compound of cyclo-peptide.

本文利用廉价易得的三苯基磷和手性L-缬氨酸作为起始原料，合成了几种普通季鏻盐和手性季铵盐，并且利用L-缬氨酸与L-苯丙氨酸甲酯反应，合成了一种新型的相转移催化剂——2，5-二酮哌嗪环类的化合物。

An unstable important intermediate ,2- methoxymethyl-hydroquinone which is very easy to oxidize and polymerize, and its precursors were first synthesized, a...

第一、二条合成线路前人未见报导，从中得到了四个苯并呋喃类衍生物，并详细地探索了环化反应的条件。

Moreover, one novel photochromic compound: 3,3-bis(4-methoxybenzyl)-3H-naphtho[2,1-b]pyran has been synthesized, which may be used in optical lenses to protect human eyes from being damaged by ultraviolet lights.

该化合物具有较好的光致变色性质，其开环式的颜色与吡啶并苯恶嗪的颜色互补，这两种化合物相结合构成第二代Transitions镜片的基础。

In Chapter 5, we studied electronic structures of 11 types of non-classical thiophene, which composed by benzene, thiophene, pyrazine and thiadiazole, respectively.

在第五章中，我们对由苯、噻吩、吡嗪和噻重氮环组成的非经典噻吩分子与乙烯(共11种)的共聚物，进行了计算研究。

Four new types of pyrimidine derivatives introduced directly by nitrogen-containing benzoheterocycles were designed and synthesized.

设计并合成了四种苯并含氮杂环取代的嘧啶类新化合物，它们的结构经 MS，IR和1 H NMR分析得到确

Ten benzoylthiourea s containing substituted pyrimidine ring were synthesized,among them seven are new compounds.

合成了10种含不同取代嘧啶环的苯甲酰硫脲类化合物，其中7个为未见文献报道的新化合物。

With L-DOPA as the starting chiral phenylalanine derivatives, construction of the skeleton of Phthalascidin was studied. Firstly, starting from L-DOPA and 3,4-dimethoxyphenylalanine, an amide 〓 was obtained, and a modeling cyclization reaction was carried out but failed to give the anticipated product.

二、对由苯丙氨酸甲酯衍生物通过Bischler-Napieralski反应合成四氢异喹啉—3—甲酯进行了研究，通过研究首次发现，生成苄基噁唑的反应是正常的B-N反应的竞争性反应，并从机理上给予了解释，所得出的结论具有一定的规律性，在杂环的合成方面具有一定的应用价值。

The synthesis of the pentacyclic skeleton of Et-743 and the construction of the five chiral centers thereof.1. The core pentacyclic skeleton of phthalascidin was constructed with L-dopa as the starting material via thirteen steps. First, two basic synthons, the C-1 functionalized tetrahydroisoquinoline compounds 8 and N-protected Z-dopa derivative 9, were prepared from L-dopa. They were coupled via amide bond to form the dipeptide compounds 10, which were the first key intermediates. Then the primary hydroxyl groups were transformed into the corresponding amino aldehydes 11 via Swern oxidation. Followed by the intramolecular Pictet-Spengler cyclization, the pentacyclic compounds 12 were synthesized.

五环骨架的构建及五个正确手性中心的确立：1.1我们以L-多巴为起始原料，经过多步官能团保护和转化合成了基本结构单元8然后和苯丙氨酸衍生物9，通过缩合反应生成酰胺中间体10，经Swern氧化得到醛化合物11，然后再次利用分子内改良的Pictet-Spengler反应一步构建c，d两环，得到五环骨架化合物12，最后，实现了21-位羰基向氰基的转化，得到了C-1位官能化的化合物14，化合物14不但具有和Et-743一致的五环骨架，而且分子中五个手性中心立体构型也与其完全相同：其中，3，位和13，位的手性中心由原料L-多巴带入，而1，位，11，位和21，位手性中心则通过不对称诱导而确立。

At present, the industry widely used method hydrodesulfurization with a substituent of dibenzothiophene class of heterocyclic compounds of the desulfurization efficiency is very low.

目前，工业上广泛采用的加氢脱硫法对带有取代基的二苯并噻吩类杂环化合物的脱硫效率很低。

About 100% yield of cyclohexanemethanol could be obtained in the presence of triethylamine if adding more catalyst and prolonging the reaction time.

在三乙胺存在下，增大催化剂用量并延长反应时间，苯甲醛可以100％的收率转化为环己基甲醇，没有出现任何副产物。

We have no common name for a mime of Sophron or Xenarchus and a Socratic Conversation; and we should still be without one even if the imitation in the two instances were in trimeters or elegiacs or some other kind of verse--though it is the way with people to tack on 'poet' to the name of a metre, and talk of elegiac-poets and epic-poets, thinking that they call them poets not by reason of the imitative nature of their work, but indiscriminately by reason of the metre they write in.

索夫农 、森那库斯和苏格拉底式的对话采用的模仿没有一个公共的名称；三音步诗、挽歌体或其他类型的诗的模仿也没有——人们把&诗人&这一名词和格律名称结合到一起，称之为挽歌体诗人或者史诗诗人，他们被称为诗人，似乎只是因为遵守格律写作，而非他们作品的模仿本质。

The relationship between communicative competence and grammar teaching should be that of the ends and the means.

交际能力和语法的关系应该是目标与途径的关系。