酯

Objective To determine the contents of residual acetone in acetoacetic ester,the raw material for the synthesis of Edaravone, by gas chromatography.Methods Sample solution was injected on a GDX column (0.18 mm～0.25 mm) with nitrogen as the carrier gas.The residue was calculated by the external standard method.

摘要］ 目的：用气相色谱法测定依达拉奉合成起始原料乙酰乙酸乙酯中丙酮的残留量方法：采用固定相二乙烯苯乙基乙烯苯型高分子孔小球（直径为0.18 mm～0.25 mm），氮气为载气，用外标法测定乙酰乙酸乙酯中残留丙酮的含量。

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 E-TOF will also be feasible and practical to assist chemists in screening the optimal reaction condition or evaluating the overall efficiency of different catalytic systems for a specific asymmetric reaction.4.For the first time,we explored chiralγ-hydroxy-α,β-acetylenic esters,which were prepared via asymmetric alkynylation,as key intermediates to the synthesis of chiralγ-butyrolactones. This convergent and enantioselective approach to chiralγ-butyrolactones is practical and easily handled with protecting group free.

这一概念包括反应产率、对映选择性、配体用量以及反应时间四个重要反应参数，不仅适用同一反应不同催化体系的横向综合性评价，而且适用于某一特定反应催化体系的优化过程，有助于研究人员选择最佳的反应条件。4、我们发展了以手性γ-羟基-α，β-炔酸酯为关键中间体完成了手性γ-丁内酯类天然产物的对映立体选择性全合成，该关键中间体能够以我们的催化体系方便的对映选择性合成，之后的官能团转换方法成熟，易于操作，无需进行繁琐的官能团保护和脱保护过程，绿色经济。

Conclution: Diester aconitum alkaloid can be changed to monoester aconitum and aconine alkaloids. Under the controled condition benzoylaconine is a major hydrolysis products.

双酯型的乌头碱可水解转化为单酯型乌头碱和乌头原碱；在控制条件下，苯甲酰乌头原碱为主要水解产物。

Determination of alantolactone and isoalantolactone in herb Inula racemosa Hook.f.by RP-HPLC.

RP-HPLC测定藏木香中土木香内酯和异土木香内酯含量。

Conclu sion: The ethyl acetate elution of ethyl acetate fraction extract of Alisma orientalis can significantly inhibit urinary calcium oxalate stone formation in rats and be the most effective constituent of Alisma orientalis .

泽泻醋酸乙酯浸膏的醋酸乙酯洗脱液能抑制实验性高草酸尿症大白鼠体内肾草酸钙晶体的形成，是泽泻抑制尿草酸钙结石形成的有效部位。

The chemical structure and applications of the alkoxy zirconates are completely analogous to those of the alkoxy titanates.

烷氧基锆酸酯的化学结构和应用完全与烷氧基钛酸酯类似。

ABSTRACT The thesis aims at the studies on the total synthesis of α-alkylidene -β-hydroxy-γ-butyrolactones.

本论文以α-亚烷基-β-羟基-γ-丁内酯类天然产物的全合成研究为主，包括三个部分：第一部分：文献综述：着重介绍了α-亚甲基-γ-丁内酯萜类，。。。

depart method suits Gao of the Z- in angelica this inside of the naphtha of angelica of fast preparation; of ester from emulsification small breast preparation is ameliorable among them Z- Gao this inside the instability of ester.

结论分离方法适合当归中Z-藁本内酯的快速制备；当归挥发油的自乳化微乳制剂可改善其中Z-藁本内酯的不稳定性。

Poly-[N-(2-hydroxyethyl)-L-glutamine] was then obtained by aminolysis of PBLG with 2-aminoethanol.

以L -谷氨酸为单体，经r -羧基的苄基保护，与光气/甲苯液反应制备L-谷氨酸苄酯的羧酸酐，均聚得L -谷氨酸苄酯，然后经由 2 -氨基乙醇胺解得聚 [N -( 2 -羟乙基)-L -谷酰胺 ] 。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。