乙酰乙酸乙酯

And then we found that ytterbium trifluoromethethanesulfonate is a powerful catalyst for the reaction of amine and ethyl acetate.

然后研究了三氟甲磺酸镱催化的胺和乙酸乙酯的反应，从而合成了乙酰苯胺类化合物。

The synthesis of the intermediate amidetriazinone was a crucial step in the synthesis of triazinone. Ethyl acetate was used as the initial material then was carried out for five steps hydrazine hydrate, triphosgene, chloroacetone, hydrazine hydrate respectively with the yield of 59.8%.

三嗪酮类化合物的合成关键是中间体氨基三嗪酮，本文以乙酸乙酯为起始原料，经过酯的肼解、成环反应、胺的烷基化、酮和肼的缩合、酰胺的水解五步反应合成中间体氨基三嗪酮，其收率达59.8%。

The propanedinitrile is synthesised from ethyl cyanoacetate by amination and elimination reaction.

由氰乙酸乙酯与氨反应生成氰乙酰胺，再经过消除反应制得丙二腈。

The condensation of aromatic aldehydes with active methylene compounds like malononitrile, cyanoacetamide and ethyl cyanoacetate has been found to proceed very efficiently at room temperature giving excellent yields, but the condensation of heteroaromatic,α,β-unsaturated and aliphatic aldehydes with active methylene compounds proceeded smoothly in 50~65℃ with good yields and the reactions of aromatic, aliphatic ketones as well as p-phthalaldehyde with malononitrile also proceeded in 75~85℃ with moderate yields.

芳香醛与活泼亚甲基化合物如丙二腈、氰基乙酸乙酯、氰基乙酰胺的缩合在室温下即能顺利进行，获得了很高的收率；而对于杂环芳醛、α，β-不饱和的醛以及脂肪醛与活泼亚甲基化合物的缩合，需在50~65℃下进行，也取得了很高的收率；对于脂肪酮、芳香酮以及二元醛与丙二腈的缩合在75~85℃下也能顺利地进行，获得中等以上的收率。

College of Veterinary Medicine, China Agricultural University, Beijing 100094, China Abstract: A method has been developed to determine residual stilbenes such as diethylstilbestrol, dienestrol and hexestrol in animal tissues using solid phase extraction and gas chromatography-mass spectrometry.

动物组织样品在碱性条件下用乙酸乙酯提取，经碳酸钠溶液液-液分配净化，再用硅胶柱固相萃取净化，洗脱液均分成两份后经氮气吹干，分别用双三甲基硅基三氟乙酰氨和七氟丁酸酐衍生，采用选择离子监测模式进行测定，外标法定量。

The free fatty acids were extracted with petroleum ether and were separated on silicon gel column chromatography. The ethyl acetate-soluble lipid fraction and water-soluble lipid fraction were subjected to hydrochloric acid-catalyzed methanolysis, then were extracted with petroleum ether, respectively.

用石油醚提取低极性组分，经硅胶柱层析分离得到游离脂肪酸；用乙酸乙酯提取酯溶性神经酰胺及其衍生脂类，提取物和残余的水溶性脂类分别经盐酸甲醇解，水解产物再用石油醚提取。

A GC headspace injection method for the determination of residual organic solvents such as methanol, ethanol, acetonitrile, dichloromethane, ethylacetate, 4 methyl 2 pentanone, toluene, DMF, chloroform and tetrahydrofuran in tazobactam was established.

建立了气相色谱顶空进样法测定三唑巴坦中甲醇、乙醇、乙腈、二氯甲烷、乙酸乙酯、甲基异丁基酮、甲苯、N ，N′-二甲基甲酰胺、氯仿和四氢呋喃等有机溶剂的残留量。

The structural assignment of Ⅱwas supported by spectral data and was confirmed by the identification of the compound as the product obtained by synthesis from triethyl orthoacetate and 2- cyanot hioacetamide.

结构的指定得到由光谱数据的支持，确认结构是通过原乙酸三乙酯和2-氰基-硫代乙酰胺合成得到的化合物。

The experimental condition of acetylating method for determining priminary alcohol and secondary alcohol catalyzed by perchloric acid in the medium of analytically pure ethylacetate is proposed.

提出了以高氯酸为催化剂，分析纯乙酸乙酯为介质，乙酰化法测定伯、仲醇的实验条件，实现了对经典方法的改进，简化了操作程

Methods: M-acetaminphen was used as an internal standard, and alkalinized samples of plasma were extracted with ethyl acetate.

以间乙酰氨基酚为内标，血浆样品经碱化后，用乙酸乙酯提取。

The objective is to subjugate and discourage the people, because that allows the elite to continue to rule unopposed.

其目的是压制和打击人民的积极性，因为这可以让实权派继续统治不会沦为反对派。

GOD,this is the second time you vanquished me!

天啊，这是第二次你打败了我！