An Improved Method for the Synthesis of N-Phenoxyacetylribonucleosides

N-phenoxyacetylribonucleosides were prepared efficiently from the reaction of ribonucleosides with phenoxyacetylchloride and 1,2,4-triazole(for adenosine and cytidine) or 1-hydroxybenzotriazole (for guanosine).     

An Improved Method for the Preparation of o-Quinodimethanes

The use of zinc/silver couple for preparation of the o-quinodimethane from 3, 6-dimethyl-1, 2-bis (bromomethyl) benzene, 1, is described.     

An Improved Method for the Conjugation of FAB' to B-D-Galactosidase from Escherichia coli

Abstract

An improved method for the conjugation of Fab' to B-D-galactosidase from Escherichia coli was developed. The enzyme with thiol groups was treated with excess of N, N'-o-phenylene-dimaleimide to introduce maleimide groups, and the maleimide-enzyme was reacted with thiol groups in the hinge of Fab' to form Fab'-B-D-galactosidase conjugate. Gel filtration of Fab' was required only once, and the recovery of Fab' in the conjugate was 71–81%, while in the previous method, gel filtration was required twice and the recovery was 31–38 %. Although the enzyme activity was decreased slightly (8–12%) by the dimaleimide treatment, the conjugate was as useful for sandwich enzyme immunoassay as that obtained by the previous method. 1gG also could be conjugated to B-D-galactosidase more efficiently in the present method than in the previous one.     

正戊醛合成方法的改进

正戊醛合成方法的改进刘瑞蓝，南志祥，郭治安（西北大学化学系西安７１００６９）关键词正戊醛，一步氧化法，共沸蒸馏，精馏醛类化合物的使用相当广泛，尤其在香料工业中越来越受到人们重视，但由于易氧化与易聚合，在加热条件下合成难度大，产率低，我们在过去研究工作...     

喹烯酮合成工艺的改进

以邻硝基苯胺为起始原料,经过氧化、Beirut反应、缩合反应3步合成产品喹烯酮,总收率73.4%.产品经HPLC分析,质量分数为98.5%.并通过m.P.、IR、1H NMR和13C NMR确证其结构.     

An Improved Method for the Preparation of 4,5-Diaminochrysazin

4,5-Diaminochrysazin was prepared from chrysazin by ethylation and nitration followed by reaction with hydroiodic acid (HI). Treatment of 1,8-diethoxy-4,5-dinitroanthraquinone with HI resulted not only in O-deethylation, but also in reduction of nitro groups with more than 95% yield. This is a unique finding and is reported for the first time with a definite improvement over literature methods and is suitable for scale-up.     

三氯苯达唑中间体合成方法的改进

以2,3-二氯苯酚与3,4-二氯-6-硝基苯胺为原料,在催化剂的存在下进行成醚反应,制备三氯苯达唑中间体。探讨和优化了合成条件,并采用液相色谱、红外光谱分析等手段确认了产物的结构。以经过改进后的中间体进行合成三氯苯达唑,最终产率达到了36.7%。     

An Improved Rapid Mixing Device for Time-Resolved Electrospray Mass Spectrometry Measurements

Time series data can provide valuable insight into the complexity of biological reactions. Such information can be obtained by mass-spectrometry-based approaches that measure pre-steady-state kinetics. These methods are based on a mixing device that rapidly mixes the reactants prior to the on-line mass measurement of the transient intermediate steps. Here, we describe an improved continuous-flow mixing apparatus for real-time electrospray mass spectrometry measurements. Our setup was designed to minimize metal–solution interfaces and provide a sheath flow of nitrogen gas for generating stable and continuous spray that consequently enhances the signal-to-noise ratio. Moreover, the device was planned to enable easy mounting onto a mass spectrometer replacing the commercial electrospray ionization source. We demonstrate the performance of our apparatus by monitoring the unfolding reaction of cytochrome C, yielding improved signal-to-noise ratio and reduced experimental repeat errors.     

对烷氧基苯甲醛合成方法的改进

对烷氧基苯甲醛合成方法的改进董恒山杨世琰＊殷元骐（中国科学院兰州化学物理研究所兰州７３００００）关键词对烷氧基苯甲醛，Ｗｉｌｉａｍｓｏｎ醚合成，Ｃａｎｎｉｚｚａｒｏ反应１９９６－０４－１８收稿，１９９６－０８－０９修回对烷氧基苯甲醛是合成液晶材料和有...     

酞菁氧钛的合成及晶型转化

酞菁氧钛以联环己烷为溶剂，以邻苯二脂及四氯化钛直接反应生成。其优点是便于分离及纯化。同时对各晶型的获得及晶型间的相互转化进行了研究，并以Ｘ－射线粉末衍射及ＦＴ－ＩＲ进行了表征，并记录了不同晶型的酞菁氧钛在室温硫化硅橡胶中的吸收光谱。     

合成FOX-7方法的改进

二氨基二硝基乙烯(FOX-7); 甲基咪唑; 合成;合成FOX-7方法的改进     

An Improved Method for the Syntheses of β-Substituted Cyclohexenones

An improved method for the preparation of β-substituted cyclohexenones is reported. Conditions were defined to effectuate the key desulfonylation-deketalization step in a mild manner. Several cyclohexenones bearing acid and/or base sensitive β-substituents were prepared by the modified method in moderate to good yields.     

An Improved Method for the Preparation of Energetic Aminotetrazolium Salts

A straightforward way for the preparation of the energetic 5‐aminotetrazolium and 1, 5‐diaminotetrazolium salts is reported. The energetic salts were readily synthesized by the reaction of 5‐aminotetrazolium nitrate or 1, 5‐diaminotetrazolium nitrate with ammonium 5‐nitroiminotetrazolate, ammonium 1‐methyl‐5‐nitroiminotetrazolate, bis(ammonium) ethylene bis(5‐nitroiminotetrazolate), and diammonium iminobis(5‐tetrazolate), respectively, in water under mild conditions. All products were recovered as highly crystalline materials in excellent yields and purities, and were fully characterized by IR spectroscopy, ¹H and ¹³C NMR spectroscopy, DSC measurements as well as elemental analyses.     

溶胶-凝胶固定葡萄糖氧化酶方法的改进

明胶;生物传感器;溶胶-凝胶固定葡萄糖氧化酶方法的改进     

一种改进的烯丙基缩水甘油醚的合成方法

烯丙基缩水甘油醚;环氧氯丙烷;烯丙醇钠;烯丙醇;合成     

An Improved Method for Micro-Fluorimetric Determination of 6-Mercaptopurine

Abstract

A sensitive and specific fluorimetric assay for 6-mercaptopurine (6-MP) is described. The method consists of enzymatic (xanthine oxidase) conversion of 6- MP to the oxypurine derivatives, followed by oxidation with acidic chromate to the corresponding 6-sulfonate. The fluorescent product has excitation and emission maxima at 330 and 400 nm, respectively. The good recovery and reproducibility were obtained. The sensitivity (the smallest amount detectables) was about 22 pg/ml for 6- MP in water. Different spiked serum samples containing 6-MP and azathioprine (AZA) were also analyzed and the sensitivity for 6-MP was about 2.2 ng/ml.     

电动流动分析的色谱分离研究

建立了一种基于增压电渗泵驱动、整体柱分离和紫外检测相结合的电动流动分析系统。研究了载流溶液中甲醇的体积分数对电渗泵空载流量、输出压强、移动相流量和分离度的影响。在4950V的外加电压下,以含0.5mmol/L六亚甲基四胺的45%甲醇溶液为泵载流,电渗泵的流量和输出压强分别为0.58mL/min和0.79MPa,以泵载流为流动相,该系统对苯和萘进行了反相色谱分离。电动流动分析系统设备简单、操作方便、功能多样。对苯和萘的分离结果表明,电动流动分析系统可用于样品的色谱分离。     

布帕伐醌的改进合成方法

布帕伐醌是一种治疗牛泰勒焦虫病的药物,其传统的合成工艺存在产率低、污染严重以及成本过高的问题。本文在目前布帕伐醌的合成工艺上进行了优化,以1,4-萘醌作为起始原料,经过4步转化合成得到布帕伐醌,反应总收率达到62%,产品纯度可达99%以上,该方法在布帕伐醌的大规模生产上具有很好的应用前景。     

An Improved Synthetic Method of Saquinavir

IntroductionThe human immunodeficiency virus(HIV)is thecausative agent of acquired immunodeficiency syndrome(AIDS).Since HIV protease is essential for the repli-cation and maturation of HIV,the inactivation of HIVprotease by either mutation or chemical in…     

Improved Method for the Preparation of Oxadiazoles from Diacyl Hydrazines

N-methylimidazole (NMI) is used as the base in the triflic anhydride (Tf₂O)–mediated formation of oxadiazoles from diacyl hydrazines. This reagent is superior to pyridine-derived bases in terms of cost and reaction profile.