苄型

The third part of this thesis is reactive simulating calculation In this section, some well-known auxiliaries are selected to compute in density functional theory B3LYP on Gaussian 03, from which the relationship between reaction active energies of transition states and enantiomeric excess of chiral products homoallylic alcohols isobtained based on relative reactive ratio theory. Using this relationship, calculations on the reaction of more than eight auxiliaries with four other aldehydes are carried out in AMI and MNDO, proving that N,N\'-dibenzyl tartamide has higher enantioselectivity than others in this reaction.

第三部分为计算化学部分，运用密度泛函理论B3LYP方法在Gaussian03软件上对已经报道的几种手性配体参与的醛不对称烯丙基化反应过程进行模拟计算，基于相对反应速率理论找出两种构型过渡态间活化能的差异与产物光学收率之间的关系；并以此为基础，用AM1和MNDO方法对上述合成的几种配体控制的反应过程进行量化计算，从而在理论上证实了N-苄基酒石酸二酰胺配体在醛的不对称烯丙基化反应中具有较高的立体选择性。

This Thesis consists of the following five pacts: Following a brief Introduction on the mechanism of reactions of coenzyme NADH models with activated ethylenic compounds is discussed. Pross-Shaik treatment is employed to analyze the results.

本论文研究了：(1)辅酶NADH模型物和活化烯烃氧化还原反应的机理，并运用Pross-Shaik构型混合模型分析了这些反应的机理；(2)用辅酶NAD~+／NADH模型物催化氧化一级和二级苄醇，还原α，β-环氧酮。

The intramolecular Reformatsky-type reaction of benzyl bromide and keto group is the key step.

其中关键步骤是苄溴与酮基的分子内Reformatsky型反应。

The synthetic route starts from penicillin G, peroxyacetic acid(8.5%) as Oxidizing Agent to get penicillin G sulfoxide; esterifided with p-nitrobenzyl bromine to synthesize penicillin G sulfoxide ester; we synthesize 3-exomethylenecepham sulfoxide ester with phthalimide potassium and 4A molecular sieve as acid scavenger to open the ring, SnCl_4 as catalyzation to close the ring. The yield is over 60%.

本研究采用的合成路线为：以青霉素G钾盐为原料，选用工业过氧化氢制备的过氧乙酸(22.3%)稀释至8.5%为氧化剂，氧化得青霉素亚砜；采用对硝基溴苄为酯化试剂，制备青霉素亚砜酯；以NCP(N-氯代邻苯二甲酰亚胺)为开环试剂，酞酰亚胺钾和4A型分子筛为酸清除剂，顺利开环；再经无水SnCl_4催化闭环得3-环外亚甲基头孢亚砜酯，最终产率在60%以上。

The present dissertation reviews the total synthesis of biotin, particularly on Hoffmann-La Roche\'s Lactone-Thiolactone approach. The Lactone-Thiolactone approach is presently the most competitive commercial route, which gives an excellent illustration of the gradual construction of the functionalized skeleton with the simultaneous solution of the stereochemical issues in a minimal number of steps.In 1970, Gerecke etc. of Roche Corp.

论文对生物素全合成的文献进行了综述，重点讨论了目前工业上最有竞争力的内酯—硫代内酯路线，展示了生物素是如何以最少的步骤去逐步构建目标产物的官能团骨架并同时解决立体化学问题的。1970年，Roche公司的Gerecke等报道了一条通过手性内酯，以较高收率并保持构型得到手性硫代内酯，从而直接合成d-生物素的方法后，该中间体内酯(3aS，6aR)-1，3-二苄基。

The intermediate product was trichloromethyl benzyl alcohols that further reacted with acetic acid to prepare the crystal rose.

结晶玫瑰化学名为醋酸三氯甲基苄酯，是花香型香精优良的定香剂[1]，它广泛应用于人们的生活和生产中。

A new unsymmetrical ONO tridentate chain ligand N-(2′-hydroxyl) benzyl-ethanolamine has been synthesized and characterized by elemental analysis, IR and 1NMR.

宗汉兴 ，林瑞森，寇福平，解永树合成了不对称氮氧杂链型配体N-（2′-羟基苄基乙醇胺，通过元素分析、IR和1H NMR等手段进行了表征。

A new tripodal aryl amide type ligand,1,1,1-tris{[(2′-benzylaminoformyl)phenoxyl]methyl}-p-toluene sulfonyl aminomethane,and its Eu(NO_3)_3,Tb(NO_3)_3 complexes have been synthesized.

合成了一个新的三足芳香酰胺型有机配体1，1，1-三[(2′-甲酰苄胺苯氧)甲基]对甲苯磺酰氨基甲烷，及其Eu(NO3)3和Tb(NO3)3的配合物，并通过元素分析、红外光谱、核磁共振氢谱和摩尔电导率进行了表征。

In the first part,we studied the nucleophilic addition reactions of aldehyde, amine,Zinc and benzyl bromide in one pot to afford homobenzyl and homoallyl amines in moderate to good yields.

第一部分的工作中，我们研究了Barbier型条件下醛，胺，锌粉，溴试剂一锅法的亲核加成反应。这种反应可以高效的得到高苄基和高烯丙基胺类化合物。

Structural differences among the three gelators are only in the varied amount of methyl groups on the benzene ring.

从分子结构的差异、亲溶剂作用、分子几何构型、相转变热焓以及溶剂极性等方面研究了三种亚苄基山梨醇衍生物凝胶剂在有机溶剂中的自组装和凝胶化机理。

Now, however, all children continue in "comprehensive" schools, and the eleven-plus determines which courses of study the child will follow.

然而现在，所有的孩子都要在综合学校继续学习，所以这次考试只是决定他们将要学习哪些课程。

Cultivatable land , and led to a general recognition that development must not be carried at the cost of agriculture .

城区的迅速扩大在很多情况下侵占了宝贵的可耕地，使人们普遍认识到发展不能以牺牲农业为代价。