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Methods: 2-ethyl aniline was used as starting material of the synthesis and was processed by acetic anhydride acylation, strong nitric acid nitraction at low temperature, and desacyl synthesis to produce 2-ethyl-5-nitro aniline. The product was then synthesized to 3-methyl-6-nitro-lH-indazole by using ring-closing reaction in the presence of NaNO2, and then ethylated to obtain 2, 3-diethyl-6- nitro-2H-indazole. The latter compound was then reduced by SnC12/Hcl to get target compound 2, 3-diethyl-6-nitro-2H-indazole.

以2-乙基苯胺为原料经醋酐酰化、浓硝酸低温硝化及去酰基保护合成2-乙基－5-硝基苯胺，后用亚硝酸钠关环得3-甲基－6-硝基－1H-吲唑，经硫酸二甲酯甲基化得2，3-二甲基－6-硝基－2H-吲唑，最后用氯化亚锡将其还原得到目标产物，通过1HNMR确定结构与目标产物一致。

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。

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％。

For the asymmetric reduction ofα-hydroxyacetophenone and ethyl 4-chloro acetoacetate,-1-phenyl-1,2-ethanediol and-ethyl 4-chloro-3-hydroxybutanoate were produced by the purified enzyme, with the 99% and 94.3% e.e. value respectively.

在纯酶水平验证了近平滑假丝酵母(Candida parapsilosis CCTCCM203011)对外消旋苯基乙二醇的拆分机理，整个去消旋过程是由-苯基乙二醇次级醇脱氢酶和羰基还原酶共同催化完成的。

OBJECTIVE:To establish the RP-HPLC method for determination of methyl hydroxybenzoate and ethyl hydroxybenzoate in oral liquid preparations METHODS:The Nova-Park C18 column(3 9mm×150mm,5μm)was used The mobile phase consisted of acetonitrile-water(25∶75)at a flow rate of 1ml/min,the detection wavelength was set at 254nm and the sensitivity was set at 0 01 AUFS RESULTS:The linear ranges of methyl hydroxybenzoate and ethyl hydroxybenzoate were 0 4 412～13 2 360μg/ml(r=0 9 999) and 0 6 672～20 0 160μg/m...

目的 ：建立内服液体制剂中羟苯甲酯和羟苯乙酯的反相高效液相色谱测定方法。方法：色谱柱：Nova -ParkC18 柱(3 9mm×150mm ，5μm)；流动相：乙腈-水(25∶75)；流速：1ml/min ；检测波长：254nm ；灵敏度：0 01AUFS。结果：羟苯甲酯浓度在0 4412～13 2360μg/ml范围内线性关系良好(r=0 9999)；羟苯乙酯浓度在0 6672～20 0160μg/ml范围内线性关系良好(r=0 9998)。结论：该方法简便、快速、准确，可用于医院制剂中防腐剂的检测。

In order to improve the thermal stability of yellow iron oxide pigments, a new balance precipitant coating silicon method with ethyl acetate as potential acid by controlling the dehydrolysis velocity of ethyl acetate was used.

为了改善铁黄颜料的耐热性，运用乙酸乙酯作为潜伏性酸试剂，研究了一种新的铁黄表面均匀包覆二氧化硅的方法，即通过控制乙酸乙酯的水解速率来实现在铁黄表面均匀包覆二氧化硅。

First, this paper reports measurements of surface tension of ionic liquid EMIES (1-ethyl-3-methylimidazolium ethyl sulfate) using the forced bubble method at 278.15 to 323.15 K and densities of EMIES using Westphal balance at 278.15 to

为此，本文以廉价工业原料合成的硫酸乙酯—1—甲基—3—乙基咪唑EMIES和对水、空气都稳定的离子液体BMIBF_4为主要对象，使用密度法和最大气泡法等实验方法对这两种离子液体及其EMIES的水溶液的性质作了如下研究工作：在278.15—338.15K范围内用Westphal天平测定了EMIES和BMIBF_4的密度，用最大气泡法测定了纯离子液体EMIES和BMIB_4的表面张力。

The results indicated that the Honeysuckle's Leaves extracts have extensive antimicrobial activities; The ethyl acetate re-extract possess the strongest antimicrobial activity; The MIC of ethyl acetate re-extract from Honeysuckle's Leaves was 0.38% against Staphylococcus aureus, which was 0.50% against Escherichia coli.

抑菌实验结果表明，金银花叶的乙醇提取物抗菌谱较广；乙醇提取物水溶液的乙酸乙酯萃取物抑菌效果最为显著；测得其对金黄色葡萄球菌和大肠杆菌的最低抑菌浓度分别为0.38%和0.50%。

By the time of its fall, most of the prisoners were writers who had written against the corruptions of the government.

到它被攻陷的时候，里面多数的犯人是写了反对政府贪污文章的作家。

The most obvious variation to ovum morphological character was that the color was changed from light green to sepiaceous in embryonic development, and all the ovums were almost hatched after 96h.

在胚胎发育过程中卵的形态特征最明显的变化是颜色从淡绿到深褐色，卵在发育96h后卵基本全部孵化。