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鐿催化的胺和乙酸乙酯的反應(yīng)，從而合成了乙酰苯胺類化合物九九视频热播。

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%.

三嗪酮類化合物的合成關(guān)鍵是中間體氨基三嗪酮国产亚洲精品ⅴa在线观看，本文以乙酸乙酯為起始原料，經(jīng)過酯的肼解曰批全过程免费视频在线观看直播、成環(huán)反應(yīng)亚洲一区免费视频、胺的烷基化作爱超A级黄色视频、酮和肼的縮合、酰胺的水解五步反應(yīng)合成中間體氨基三嗪酮亚洲国产一区二区三区，其收率達(dá)59.8%欧美爱性真人在线视。

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

由氰乙酸乙酯與氨反應(yīng)生成氰乙酰胺，再經(jīng)過消除反應(yīng)制得丙二腈8×8x永久华人免费网址入口。

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.

芳香醛與活潑亞甲基化合物如丙二腈啪啪啪试看乱码、氰基乙酸乙酯、氰基乙酰胺的縮合在室溫下即能順利進(jìn)行国产午夜精品理论免费视频，獲得了很高的收率网站大全色网站；而對于雜環(huán)芳醛、α大路色视频，β-不飽和的醛以及脂肪醛與活潑亞甲基化合物的縮合人人人色人人在线视频，需在50~65℃下進(jìn)行，也取得了很高的收率。av免费网站；對于脂肪酮www.99riav.1vip、芳香酮以及二元醛與丙二腈的縮合在75~85℃下也能順利地進(jìn)行，獲得中等以上的收率特黄毛片在线观看。

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.

動物組織樣品在堿性條件下用乙酸乙酯提取久草性爱中文黄片免播，經(jīng)碳酸鈉溶液液-液分配凈化，再用硅膠柱固相萃取凈化曰韩一级黄片，洗脫液均分成兩份后經(jīng)氮氣吹干色久悠悠中文字幕，分別用雙三甲基硅基三氟乙酰氨和七氟丁酸酐衍生，采用選擇離子監(jiān)測模式進(jìn)行測定无码精品日韩网站视频，外標(biāo)法定量精品自拍第2页在线。

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.

用石油醚提取低極性組分，經(jīng)硅膠柱層析分離得到游離脂肪酸视频一区视频在线；用乙酸乙酯提取酯溶性神經(jīng)酰胺及其衍生脂類私人福利影院，提取物和殘余的水溶性脂類分別經(jīng)鹽酸甲醇解，水解產(chǎn)物再用石油醚提取国产妇女。

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.

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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.

結(jié)構(gòu)的指定得到由光譜數(shù)據(jù)的支持，確認(rèn)結(jié)構(gòu)是通過原乙酸三乙酯和2-氰基-硫代乙酰胺合成得到的化合物亚洲一区二区三区久久精品视频。

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.

提出了以高氯酸為催化劑偷拍亚洲，分析純乙酸乙酯為介質(zhì)，乙趸粕悠翟谙呙夥压劭椿苹仆荆化法測定伯欧美一级婬片欧美人妻、仲醇的實驗條件，實現(xiàn)了對經(jīng)典方法的改進(jìn)午夜性爱视频在线，簡化了操作程

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

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