查询词典 dibenzyl

The auxiliary can be recovered in high yield (81%) only by filtering and recrystallization. Besides, some other aldehydes have been chosen to test the enantioselectivity of N,N\'-dibenzyl tartamide, in comparison with two other allylaborates reagents developed previously by Roush and Brown, respectively. The results show that %e.e. of homoallylic alcohol is superior to that of the former, and approaches the Brown reagent.

产物经S_N2反应得瑞格列萘中间体-甲基烯丙基-2-氯苯基-叠氮甲烷(17)；同时，将筛选出的新型手性配体N-苄基酒石酸二酰胺用于其他几种醛(正丁醛，异戊醛和环己醛)的不对称烯丙基化反应，并与广泛应用的Roush配体(22)和Brown配体(27)相比较，发现其立体选择性优于Roush配体，并接近Brown配体，但明显具有可回收利用的优势。

In the second part of the thesis, we discussed a L-proline-catalyzed direct Aldol reaction between L-amino acid-derived N,N-dibenzyl -amino aldehydes 15 and acetone, cyclopentanone or hydroxyacetone, which afforded (-amino--hydroxy- or (-amino-,(-dihydroxy-ketones in good to excellent yields (up to 94%) and diastereoseletivities (up to 94.9%).

发现许多情况下，反应的产率和de值超过90%。接着，在碱性条件下，我们将L-亮氨酸衍生的N，N-二苄基--氨基醛15g与羟基丙酮反应得到的主要产物(，-二羟基-γ-氨基酮171d与次溴酸钠反应，得到了具有抗肿瘤活性的天然产物PM-94128的氨基酸片断184。

Benzyl bromide was synthesized from dibenzyl ether and hydrobromic acid with SO42-/ TiO2 as catalyst and cyclohexane as dehydrant.

以二苄醚和氢溴酸为原料，SO42-/TiO2为催化剂，环已烷为带水剂，合成了溴化苄。

This method is simple, rapid, accurate and effective for testing the impurity dibenzyl-(2-chlorophenyl) methanol in Clotrimazole and Betamethasone Dipropionate cream and for its content determination.

所建方法准确、简便、快速，适用于克霉唑倍他米松乳膏中克霉唑和二丙酸倍他米松的含量测定和杂质二苯基-（2-氯苯基）甲醇的含量测定。

The photodegradation of dibenzyl sulfone catalyzed by semiconductor TiO2 particles under UV irradiation was investigated.

以半导体TiO2为催化剂，对二苄基砜（ASO2A）进行光催化降解，研究降解二苄基砜的反应条件，讨论了TiO2为催化剂降解ASO2A的实质，初步确定反应机理。

Benzyl acetate was synthesized with dibenzyl ether and carboxylic anhydrides as raw material and solid super acid SO 2-_4/TiO_2 as catalyst.

以固体超强酸SO2 -4/TiO2 为催化剂，二苄醚和乙酸酐为原料合成乙酸苄酯，并考察了影响反应的主要因素。

Dibenzyl sulfoxide and dibenzyl sulfone were synthesized from dibenzyl sulfide oxidated with H 2O 2 without catalyst.

在无催化剂条件下利用过氧化氢氧化二苄基硫醚合成了二苄基亚砜和二苄基砜。

Two monomers,bispmpargyl ether of bisphenol-Aand 4,4'-biphenyl dibenzyl azide were synthesized and characterized with FT-IR,1H-NMR and elementary analysis.

合成了两种单体双酚A二炔丙基醚与4，4′-联苯二苄叠氮，研究了一种新的低温聚合体系——双酚A二炔丙基醚与4，4′-联苯二苄叠氮在烘箱中的本体聚合行为。

The calibration curve was linear (r=0.9999) within the range of 5.096×10-3~0.2038 μg/mL for dibenzyl-(2-chlorophenyl) methanol. The average recovery was 99.83% with repeatability precision RSD=1.26%(n=9). The limit of dibenzyl-(2-chlorophenyl) methanol was 2.00%.

，平均回收率为100.34%，RSD=0.95%（n=9）；杂质二苯基-（2-氯苯基）甲醇在5.096×10-3~0.2038 μg/mL范围内线性关系良好（r=0.9999），平均回收率为99.83%，RSD=1.26%（n=9），限度为不得大于克霉唑标示量的2.00%。

This work, concentrated on the asymmetric allylation of aldehydes controlled by different chiral auxiliaries prepared from rotational pure tartaric acid, can be divided into three parts.The first part aims to review the developments of chiral drugs and asymmetric synthesis, from which derived the present research topic backgrounds and works.Synthesis and applications of allylation from aldehydes are the second part of the thesis. By optimizing the reaction conditions, such as solvents, temperature, time and chiral auxiliaries like N,N\'-dibenzyl tartamide, N,N\'-p-dimethylphenyl tartamide, N,N\'-o-dimethylphenyl tartamide, N,N\'-o-dichlorophenyl tartamide, N,N\'-a-dinaphyl tartamide, N,N\'-dicyclohexyl tartamide and N,N\'-diphenyl tartamide, ideal experimenttal conditions are obtained according to HPLC monitoring, as well as the auxiliaries\' recoveries experiments. Starting from benzaldehyde and 3-bromopropaldehyde, N,N\'-dibenzyl tartamide is considered the best auxiliary in this reaction.

本文介绍了醛的不对称烯丙基化反应，以光学纯酒石酸为原料，研究了不同构型手性配体在醛的烯丙基化反应中的立体选择性，全文共分三部分十个章节：第一部分对当前手性药物和手性技术进行了概述，并由此展开了本文的研究背景和任务；第二部分为有机合成部分，对醛的不对称烯丙基化反应进行了深入探讨，以苯甲醛为原料对反应条件进行优化，在优化的反应条件下对制备的七种可回收手性酰胺配体(N-苄基酒石酸二酰胺、N-对甲苯基酒石酸二酰胺、N-邻甲苯基酒石酸二酰胺、N-邻氯苯基酒石酸二酰胺、N-a-萘基酒石酸二酰胺、N-环己基酒石酸二酰胺和N-苯基酒石酸二酰胺)进行筛选，优化配体回收实验条件，最终确定出N-苄基酒石酸二酰胺在苯甲醛的不对称烯丙基化反应中具有较大优越性，结晶回收的手性配体光学纯度保持不变。

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。