EPA甲酯和DHA甲酯标准样品的制备和结构解析

从鱼油中分离制备得到二十碳五烯酸（EPA）甲酯和二十二碳六烯酸（DHA）甲酯,采用红外光谱、质谱、核磁共振波谱等手段对EPA甲酯和DHA甲酯的结构进行表征,提供了不饱和脂肪酸甲酯标准物质研制基础。样品的红外光谱（IR）、质谱（MS）、核磁共振谱图（1HNMR、13CNMR）所给出的结构信息与EPA甲酯和DHA甲酯的化学结构式相符,并通过DEPT谱和I3C-1H COSY化学位移相关谱（HMBC）对各共振峰进行了指认,样品的谱图数据与文献报道基本一致。     

胆酸甲酯(甲基)丙烯酰基衍生物的合成

以(甲基)丙烯酰氯为酰化剂,三乙胺做缚酸剂合成了分子中含有1~3个(甲基)丙烯酰基的胆酸衍生物。结果显示,以酰氯作酰化试剂,胆酸甲酯分子中3个羟基的反应活性顺序是:C3-OH>C12-OH>C7-OH。     

A Simple and Mild Procedure for the Preparation of Bile Acid Methyl Esters

Bile acid ester are useful intermediates in reaction schemes yielding bile alcohols^2–5 and other acid derivatives. Reported methods for the preparation of bi le acid methyl or ethyl esters consist of dissolving the bile acid in a large excess of absolute alcohol (ei ther methanol or ethanol) containing a catalytic amount of concentrated mineral acid (either hydrochloric or sul furic). Alternately bile acid methyl esters have been prepared using diazomethane thus avoid the use of strong mineral acids. This very simple methods, presented howe ver several drawbacks. In the former method, the use of strong mineral acids, expecially hydrochloric acid, on polyhydroxy steroids, such as bile acids, can often cau se the formation of undesirable side products.     

新的溶致液晶性高分子——N-马来酰化壳聚糖的合成与表征

新的溶致液晶性高分子——Ｎ┐马来酰化壳聚糖的合成与表征董炎明李志强（厦门大学化学系福建厦门３６１００５）壳聚糖（（１，４）－２－氨基－２－脱氧－β－Ｄ－葡聚糖）是甲壳素经脱乙酰化得到的一种生物高分子。它的原料是海产品加工厂的废料，因而来源十分丰富，作...     

除虫剂二氯菊酸甲酯的手性分离

在全甲基－β－环糊精（ＰＭＢＣＤ）,２,６－０－二丁基－３－０－丁酰基－β－环糊精（ＤＢＢＣＤ）,２,６－０－二壬基－３－０－三氟乙酰基－β－环糊精（ＤＮＢＣＤ）及混合固定相（ＰＭＢＣＤ＋ＤＢＢＣＤ）等５种手怀固定相上分离了除虫剂二氯菊酸甲酯（ＰＴ）的对映异构体,并测定了部分热力学数据。发现ＤＰＡＢＣＤ对ＰＩ的分离效果最好,且不同固定相对ＰＩ具有相同或相似分机理。     

Application of the Curtius Rearrangement in a Convenient Preparation of 3-Aminopyrazinecarboxylic Acid,Methyl Ester

An efficient and convenient synthesis of 3-aminopyrazinecarboxylic acid, methyl ester (7) has been achieved through the use of a Curtius rearrangement.     

Liquid Chromatographic Analysis of Bile Acid Methyl Esters

Abstract

Methods have been developed for the qualitative and quantitative analysis of hydroxy and keto derivatives of methyl cholanates utilizing a ¼″ by 1′ μPorasil column, various mixtures of hexane and ethyl acetate and a refractive index detector. The system has been calibrated for some of the methyl dihydroxycholanates using 3α;,7α-dihydroxy-12-oxocholanate as an internal standard and applied to the analysis of the mixtures of diols resulting from the reduction of methyl 3,12-dioxocholanate with NaBH₄ and with Raney nickel.     

4-叔丁氧羰酰胺基-呋喃-2-甲酸甲酯的合成

以呋喃甲醛为起始原料,经过5步反应合成了天然产物Proximicin A的     

A Practical Synthesis of 6-Acetylsalicylic Acid Methyl Ester

A new and efficient synthesis of the title compound is reported. The method includes a regioselective ortho-lithiation step in none polar solvents at an ambient temperature and the overall yield for 5 steps is more than 70% from a commercially available 3-hydroxyacetophenone.     

Acylation of Dibenzo-18-crown-6 with Alkali-metal Acetates in Polyphosphoric Acid

The acylation of dibenzo-18-crown-6 by lithium, sodium, and potassium acetates in polyphosphoric acid was studied. Complexes of dibenzo-18-crown-6 with the acetates were obtained. A new method is proposed for the production of mono- and diacetyldibenzo-18-crown-6 by the reaction of dibenzo-18-crown-6 complexes with metal acetates in polyphosphoric acid. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1146–1149, August, 2005.     

dl-六甲基化丹酚酸A甲酯的合成

以2,3二-甲氧基苯甲醛为原料,经还原、溴化、Wittig反应、在正丁基锂作用下醛基化、Knoevenagel反应生成四甲基化丹酚酸F(9),9再与草酰氯反应成酰氯后与甲基化丹参素甲酯反应得到dl-六甲基化丹酚酸A甲酯,其结构经1HNMR和MS表征,总收率44.7%。     

脂肪酸甲酯乙氧基化物的气相色谱分析

用0.5 mol/L KOH乙醇溶液水解脂肪酸甲酯乙氧基化物(FMEO),酯键断裂,其疏水基甲 酯化、亲水基硅醚化后分别用气相色谱法测定其组成,并采用峰面积归一化法进行了组分的 定量。成功测定了各种FMEO样品的疏水基组成和环氧乙烷(EO)加成数分布,方法简单,重复性 好,尤其是对原料为混碳脂肪酸甲酯的FMEO更有意义。     

Synthesis of 2,3-Seco-Derivatives of Dihydrobetulonic Acid and its Methyl Ester

Chemistry of Natural Compounds - 2,3-Secolupane aldehydonitriles with an isopropyl fragment were synthesized via Beckman fragmentation of ring A of triterpene α-hydroxyoximes obtained from...     

6-羧甲硫基-7-硝基庚酸甲酯二环己基铵盐的合成

生物素（即维生素Ｈ）是重要的维生素，对人体及家禽的生长起着重要的作用［１］。现在国内所用生物素均从日本进口，而且未见国内有合成及应用方面的报道，因此进行生物素合成的研究是非常必要的。我们采用了由己内酯出发经中间体６－羧甲硫基－７－硝基庚酸甲酯二环己基...     

2-氨基-6,7-二甲氧基-喹啉-3-甲酸甲酯的合成

以3,4-二甲氧基苯甲醛为起始原料,经硝化、缩合和还原反应合成了2-氨基-6,7-二甲氧基-喹啉-3-甲酸甲酯,其结构经UV,1HNMR,IR和MS表征。     

手性糖基锌卟啉对手性氨基酸甲酯的分子识别

合成了手性四糖基取代锌卟啉(Zn-A)的三种阻转异构体αβαβ-Zn-A、ααββ-Zn-A和αααβ-Zn-A以及一种单糖基取代锌卟啉(Zn-B), 并通过可见光谱滴定法和圆二色(CD)光谱滴定法研究了它们对手性氨基酸甲酯(L/D-LeuOMe, L/D-ThrOMe, L/D-ValOMe和L/D-PheOMe)客体的分子识别行为. 研究发现, 三种锌卟啉对L型氨基酸甲酯的缔合常数均要高于D型, 其中ααββ-Zn-A的对映体选择性(K_L/K_D)最高可达4.75, 可用于L型氨基酸甲酯的选择性识别. 不同的Zn-A 阻转异构体对手性氨基酸甲酯的缔合常数给出相同的顺序:K^θ(LeuOMe) > K^θ(ValOMe) > K^θ(ThrOMe) > K^θ(PheOMe);主体Zn-B对手性氨基酸分子的缔合常数顺序为K^θ(PheOMe) > K^θ(LeuOMe) > K^θ(ValOMe) > K^θ(ThrOMe). 同时, 以咪唑为探针分子研究了非手性分子对Zn-A构象的影响, 发现非手性分子咪唑与手性主体结合后, 也可对主体的构象产生影响. Zn-A的三种阻转异构体与氨基酸甲酯和咪唑类客体的缔合常数关系均为K^θ(ααββ-Zn-A) > K^θ(αβαβ-Zn-A) > K^θ(αααβ-Zn-A).     

Bile Acid Derivatives in the Preparation of New Synthetic Polymers

Bile acids are compounds stored in the gallbladder and help in the digestion of fats and lipids in the gastro-intestinal tract. These amphiphilic compounds can interact favorably with both hydrophilic and hydrophobic molecules. To improve the biocompatibility of the polymers used in biomedical and pharmaceutical applications, we have synthesized various derivatives of bile acids and used them in the preparation of new polymeric materials, including both polyaddition and polycondensation products. The use of the bile acid derivatives should improve the biocompatibility of the polymers, especially when they are used in the gastrointestinal tract. Even in case of decomposition, these derivatives are not expected to cause serious problems of toxicity. We have used bile acids in the preparation of both stable polymers (hydrogels) and degradable ones (polyanhydrides).     

反应性马来酸十二酯在苯丙乳液制备中的应用

马来酸酐与月桂醇反应合成了马来酸十二酯(1),以1为反应型乳化剂制备了苯丙乳液(2和2′).对2和2′的结构与性能进行了初步研究,探讨了聚合工艺、反应时间、单体转化率、温度等对2′性能的影响.制备2′的最佳反应条件为:w(1)=2.5%,用水量50%-60%,采用预乳化法,于75℃～80℃反应6 h,单体转化率96.2...     

Use of Sep-PakR C18 Cartridges for the Collection & Concentration of Environmental Samples

Abstract

High Pressure Liquid Chromatography (HPLC) is being increasingly employed in environmental analysis. However, HPLC is somewhat limited by the sensitivity of the detection systems commercially available. Many are not sensitive enough to cope with the lower levels being demanded by various governmental agencies. The purpose of this study is to show the efficiency of a simple sampling device, a SEP-PAK which not only allows efficient on-site sampling but offers the ability to concentrate samples down to a level where UV or fluorescent detection can determine trace quantities in the ppb range.     

脱氧胆酸类分子钳对氨基酸甲酯的手性识别

紫外光谱法;脱氧胆酸类分子钳对氨基酸甲酯的手性识别