乙酯

The ammonia was evaporated under decreasing pressure, and the precipitate was filtered off and the liquid was poured into hot saturated picric acid solution to get picrate with a yield of 85.0%. The optimum process starting from imidazole-4,5-dicarboxylic acid was: imidazole-4,5-dicarboxylic acid in acetic anhydride was refluxed to get imidazole-4-carboxylic acid, and the product was esterification in ethanol with a catalyzer of concentrated sulfuric acid to get ethyl imidazole-4-carboxylate, at last the compound above was reduced by LiAlH4 in ether at room temperature to get the target compound, the total yield of this route was 49.6%.

以4，5-二羧酸咪唑为原料的较佳工艺：1 脱羧反应：4，5-二羧酸咪唑40g，醋酐1200ml，回流10h，过滤并将滤液浓缩至干，所得固体加至50%的乙醇溶液回流，过滤并将滤液自然冷却过夜，过滤得固体；2 酯化反应：4(5)-羧酸咪唑50g，乙醇1000ml和浓硫酸60ml，加热回流2h，5%浓度NaOH溶液调节至pH＝8，减压浓缩至干，加入少量水回流，自然冷却过夜并过滤得固体；3 还原反应：LiAlH410g，乙醚300ml和4(5)-羧酸咪唑乙酯28g，常温反应1.5h，小心滴加25ml水后过滤，滤渣溶于300ml甲醇中并过滤，收集所得乙醚和甲醇滤液浓缩至干，将所得固体溶于300ml乙醇中加热回流，后将溶液浓缩至约30ml，冷却并过滤得固体，该路线总收率为49.6%。

Yields from chiral bisoxazolines (5a) with diethyl oxalate using NaOCH〓 as base for the first time. The structures of chiral multioxazolines and their intermediates, multi (β-hydroxylamide) s, were characterized by 〓H NMR, IR, mass spectra and elemental analysis. The catalytic activities and enantioselectivities of chiral multi (β-hydroxylamide) s (4) and chiral multioxazolines (5～8) were investigated by using acetophenone and β-acetonaphthone as former chiral ketone, KBH〓 or NaBH〓 as reductive reagent in chapter three.

在此基础上，对合成方法作了创新，以羧酸或酯为原料，在无催化剂的条件下与手性α-氨基醇反应，通过回流分水或脱醇的方法，一步反应合成了手性多噁唑啉（5～8），产率为89.2%～98.4%；以手性双噁唑啉（5a）为原料，在NaOCH〓的作用下，与草酸二乙酯反应，首次合成了呋喃类双嗯唑啉（6a），产率为72.9%～75.6%。

The target compound 1 was successfully prepared via esterification, reduction, bromization and cyanation processes by using L--malic acid (2), which is an inexpensive and easily available starting material. The overall yield was 56.7%.

以廉价、易得的L--苹果酸为起始原料，经酯化、还原、溴代和氰化四步反应得到目标化合物-4-氰基-3-羟基丁酸乙酯，合成总收率为56.7%。

F. which belongs to the Celastraceae Tripterygium plant, its extraction acetylacetic ester was used in clinic preparation, the primary component is epoxy terpenoid lactone.

为卫矛科雷公藤属植物，临床制剂使用的是雷公藤根的乙酸乙酯提取物，主要成分为环氧二萜内酯类化合物。

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%。

When diethyl carbonate was used as transesterification reagent,the convertion of phenol and the yield of DPC had improved,but the extant was small.

以碳酸二乙酯为酯交换试剂，苯酚的转化率和DPC的产率都有所提高，但提高的幅度不大。

Radiation-induced grafting of binary vinyl monomers of styrene/ maleic anhydride, St/ dimethylamino ethyl methacrylate and St/ vinyl acetate onto cotton cellulose was carried out byγ- radiation from a60 Co source at room temperature under nitrogen.

在氮气气氛下用γ线辐照的方法在棉纤维上接枝苯乙烯／来酸酐、乙烯／基丙烯酸二甲胺乙酯、乙烯／酸乙烯酯二元单体。

Radiation-induced grafting of binary vinyl monomers of styrene/maleic anhydride, St/dimethylamino ethyl methacrylate and St/vinyl acetate onto cotton cellulose was carried out by γ-radiation from a 60Co source at room temperature under nitrogen.

在氮气气氛下用γ射线辐照的方法在棉纤维上接枝苯乙烯/马来酸酐、苯乙烯/甲基丙烯酸二甲胺乙酯、苯乙烯/醋酸乙烯酯二元单体。

Radiation-induced grafting of binary vinyl monomers of styrene/maleic anhydride, St/dimethylamino ethyl methacrylate and St/vinyl acetate onto cotton cellulose was carried out by γ-radiation from a 60Co source at room temperature under nitrogen.

闫宇，伊敏，彭金粉，翟茂林*，哈鸿飞摘要：在氮气气氛下用γ射线辐照的方法在棉纤维上接枝苯乙烯/马来酸酐、苯乙烯/甲基丙烯酸二甲胺乙酯、苯乙烯/醋酸乙烯酯二元单体。

Anhydrous ethanol ; glacial aletic acid ; anhydrous aluminium ; ethyl acetate ; catalyzed esterize

无水乙醇；冰乙酸；无水三氯化铝；乙酸乙酯；催化酯化

Singer Leona Lewis and former Led Zeppelin guitarist Jimmy Page emerged as the bus transformed into a grass-covered carnival float, and the pair combined for a rendition of "Whole Lotta Love".

歌手leona刘易斯和前率领的飞艇的吉他手吉米页出现巴士转化为基层所涵盖的嘉年华花车，和一双合并为一移交&整个lotta爱&。

This is Kate, and that's Erin.

这是凯特，那个是爱朗。