查询词典 ethyl acetoacetate

In our research on study chemical reaction of active methylene compounds and brom-acetophenone. Because of brom-acetophenone is compound that contain carbonyl and halogen ,which will take place electrophilic substitution and nucleophilic addition. When active methylene compounds are ethyl acetoacetate and β-diketone, controlling reaction condition, we have found that mono-substitution's production and di-substitution's. production is isolated; active methylene compounds are acetoacetanilide and acetoacetanilide derivate, pyrrolidin-2-one derivants were obtained by substitution and close-ring reaction .but there is no report about it.

本文是让活泼亚甲基类化合物与溴代苯乙酮发生化学反应，由于溴代苯乙酮是含有羰基的卤代烃结构，它可以发生亲电取代和亲核加成反应，当活泼亚甲基类化合物为乙酰乙酸乙酯和β-二酮时，控制反应条件可以发生单取代和双取代两种产物；当活泼亚甲基类化合物为乙酰乙酰芳胺类化合物来反应时，溴代苯乙酮中的羰基与氨基会发生分子内的关环反应生成吡咯烷-2-酮衍生物，这在以前的研究中是没有发现的。

Thus, 3 mol of Ethyl acetoacetate were treated with 2 mol of formaldehyde to yield 80% of I.

用2摩尔的甲醛处理3摩尔的乙酰乙酸乙酯可得到80%的I。

The condensation of 3-Ethoxyphthalide was also conducted with ethyl acetoacetate and ethyl cyanoacetate.

对3位延伸出一个和两个碳原子的胺类衍生物的质谱裂解规律进行了探讨。

When MAA yeast was used to catalyze other systems, such as reducing ethyl 4-chloroacetoacetate to ethyl-4-chloro-3-hydroxybutyrate and ethyl acetoacetate to ethyl-3-hydroxybutyrate, the yield also improved at various degrees.

用此酵母在水相中催化乙酰乙酸甲酯的还原，其得率较普通面包酵母要高。pH和温度对MAA酵母与普通面包酵母都有相同的影响。

For the α-arylation of ethyl acetoacetate, the product was α-aryl ethyl acetoacetates, rather than ethyl a-arylacetates which are the major products in other catalytic systems.

较为惰性的氯代芳烃在Pd2/L1的催化下，也能够跟1，3-二羰基化合物发生α-芳基化反应。

Optically active ethyl-3-hydroxybutyrate,a useful chiral synthon,was prepared by stereoselective reduction of ethyl acetoacetate of the bread yeast in organic solvent.

利用面包酵母在非水相中不对称还原乙酰乙酸乙酯，制备了光学活性的手性化合物S-3-羟基丁酸乙酯。

The optimum reaction conditions were: the molar ratio of ethyl acetoacetate to ethylene glycol was 1:1.8,the quantity of catalyst was equal to 2% ethyl acetaoacetate,amount of cyclohexane was 20mL,and the rea...

在优化条件下反应，苹果酯收率达到93.1%，选择性接近100%。实验表明，磺化炭是合成苹果酯的优良催化剂，与其他酸催化剂相比，它还具有活性高、用量少、无污染等突出的优点。

For the α-arylation of ethyl acetoacetate, the product was α-aryl ethyl acetoacetates, rather than ethyl α-arylacetates which are the major products in other catalytic systems.

较为惰性的氯代芳烃在Pd2/L1的催化下，也能够跟1，3-二羰基化合物发生α-芳基化反应。

Base played a crucial role in this reaction: in the Pd2/L1 catalyzed α-arylation of ethyl malonate, K3PO4 is the base of choice; in the α-arylation of ethyl acetoacetate, K2CO3 is the most effective base.

在这类催化反应中，碱的选择具有重要的影响：以K3PO4为碱， Pd2/L1催化体系在丙二酸二乙酯的α-芳基化中，富电子溴代芳烃显示较好的活性； Pd2/L1催化的乙酰乙酸乙酯α-芳基化时，以 K2CO3为碱，催化体系显示较好的活性，这个催化体系可控制反应得到α-芳基乙酰乙酸乙酯，而不是脱乙酰基的产物。

Methyl-l, 3-oxazine-2,4-dione are prepared from ethyl acetoacetate and ethyl carbamate at 140 for 6h, catalysted by zinc acetate, giving to 48.8% yields which is 33% more than the literature value.

选用醋酸锌作催化剂，使乙酰乙酸乙酯与氨基甲酸酯在140℃反应6h，合成6-甲基-1，3-噁嗪-2，4-二酮，产率达48.8％，较文献报道值高出了33％。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。