(S)-甘油醛缩丙酮的新合成方法

(S)-甘油醛缩丙酮是一种用来合成一些手性药物和具有光学活性的天然产物的重要前体,本文以L-抗坏血酸为原料,经高压氢化还原、缩合反应、氧化剂氧化等步骤合成(S)-甘油醛缩丙酮.同时考察了不同的反应条件对产品收率的影响.     

S-甘油醛缩丙酮的合成及其Wittig反应

以L-抗坏血酸为原料合成了S-甘油醛缩丙酮;研究了S-甘油醛缩丙酮的Wittig反应立体选择性.     

(+)-甘油醇缩丙酮合成工艺的研究

研究了以无水氯化锌为催化剂,D-甘露醇与丙酮缩合反应合成二异亚丙基缩合物的最适宜反应条件,产率可达65%。并通过NaIO4氧化断链,NaBH4还原得到(+)-甘油醇缩丙酮。分析了每步反应产物各组分的情况,发现副产物对目标产物的合成并无影响。     

昆虫信息素结构鉴定和合成的研究 ⅩⅥ.午毒蛾光学活性性信息素及其三个光学异构体的合成

本文报道的一条合成路线是以(+)-甘油醛缩丙酮(2)为原料,各经过9～10步反应可分别合成午毒蛾光学活性性信息素1a及其三个光学异构体1b～d,总得率达20～30％。     

由谷氨酸合成具有光学活性的齿小蠹二烯醇

齿小蠹二烯醇(Ipsdienol,2-甲基-6-甲叉基-2,7-辛二烯-4-醇,1)是手性昆虫信息素.S( )对映体,它首次从齿小蠹(Ips paraconfusus Lanier)的粪便中分离出来.后来又发现其它种小蠹虫的信息素也含有这种成份.R(-)齿小蠹二烯醇是另外一种齿小蠹(Ips pini)信息素的主要组份.Mori,Ohloff 等报道三种方法合成光学活性的齿小蠹二烯醇.所用手性原料为 R( )甘油醛缩丙酮、R( )羟基丁二酸及( )或(-)马鞭烯酮(verbenone).     

光学活性3-(1′-羟基乙基)-4-乙酰氧基-β-内酰胺的立体选择性合成

(1′R,3R,4R)-N-取代-3-(1′-羟基乙基)-4-乙酰氧基-β-内酰胺(3)是合成青霉烯和碳青霉烯类β-内酰胺抗生素的关键中间体.以廉价的L-抗坏血酸为原料,制得S-缩异丙氧叉甘油醛(5),与胺反应定量转变成相应的手性亚胺(6a～6d),6与双烯酮[2+2]环加成反应,高立体选择性地合成3(S)-乙酰基-β-内酰胺(Sa～8d),其非对映体过量由类似反应的80％提高到接近100％.8a经四步反应得到目标化合物3a.     

索非布韦核苷中间体异构体的合成

以S-甘油醛缩丙酮为原料,经Wittig反应、高锰酸钾氧化、磺酰化、氟化、水解、内酯化得索非布韦关键中间体的异构体 (3R,4R,5S)-3-氟-4-羟基-5-(羟基甲基)-3-甲基四氢呋喃-2-酮,优化反应条件：n(磺酰氯)/n(化合物3)=1.6/1.0,温度为-10℃,反应2 h;氟化试剂为TEAF(四乙基氟化铵),温度为100 ℃,反应3 h,制得5S-核苷的总收率为14.21%,化学纯度97.5%,ee值98.4%;经¹HNMR, MS(ESI)和IR表征。     

(±)-6,7-丙酮缩二醇-3-酮-庚酸乙酯合成研究

用对甲苯磺酸-2,3-丙酮缩甘油酯(2)与乙酰乙酸乙酯盐、碳酸二乙酯反应, 制备β-酮酯类衍生物1. 以(±)-1,2-丙酮缩甘油为起始物, 经对甲苯磺酰化、亲核取代、脱羧等反应, 方便、高产率地合成了6,7-丙酮缩二醇-3-酮-庚酸乙酯(1). 试图通过对甲苯磺酸-2,3-丙酮缩甘油酯(2)和乙酰乙酸乙酯双阴离子反应制备6,7-丙酮缩二醇-3-酮-庚酸乙酯(1)未获成功. 所合成的化合物经元素分析, IR, ¹H NMR, ¹³C NMR和MS光谱表征.     

棒丝氨酸的全合成研究 Ⅰ.从D-葡萄糖合成3-[(3′R,5′S)-7′-氧代-1′-氮杂-4′-氧杂双环[3.2.0]-庚-3′-基]-3-O-苄基-(2S,3S)-丝氨酸及其(3′R,5′R)-差向异构体

以D-葡萄糖为原料经侧链氨基酸合成,与β-内酰胺缩合,嗯唑烷环合和除保护基等反应合成了棒丝氨酸的O-苄基衍生物,3-[(3′R,5′S)-7′-氧代-1-氮杂-4-氧杂双环[3.2.0]-庚-3′-基]-3-O-苄基-(2S,3S)-丝氨酸(17)及其(3′R,5′R)差向异构体(18)。     

甾体化合物——XLVIII.以高锰酸钾使△~(5,16,20)-孕甾三烯-3β,20-二醇二乙酸酯羟基化

△~(5,16,20)-孕甾三烯-3β,20-二醇二乙酸酯(V)经高锰酸钾处理而获得一羟基化产物,此物的结构经初步推定为X,而不是前人所拟的VI.四醇化合物(VIII)用丙酮-高氯酸处理所得的缩丙酮化合物经证明为XII,而文献报导此反应生成XIII可能是不正确的.XIII已经另从IX合成.这些结果使我们怀疑其他一些具16α,17α,21-三羟-20-酮结构的甾体化合物与丙酮反应生成16,17-缩丙酮化合物的推定的正确性.     

Construction of Multi‐Substituted Benzenes via NHC‐Catalyzed Reactions of Carboxylic Esters

A carbene‐catalyzed ester activation reaction for the synthesis of multi‐substituted benzenes is developed. Tetra‐substituted benzene compounds are efficiently synthesized through this methodology. Compared with aldehyde substrates used in previous reports, the ester substrates used here are much more readily available and inexpensive. In addition, the TEMPO oxidant used here is more inexpensive than the quinones commonly used in related carbene‐catalyzed reactions.     

Exact solutions of lattice polymer models

We consider directed path models of a selection of polymer and vesicle problems. Each model is used to illustrate an important method of solving lattice path enumeration problems. In particular, the Temperley method is used for the polymer collapse problem. The ZL method is used to solve the semi-continuous vesicle model. The Constant Term method is used to solve a set of partial difference equations for the polymer adsorption problem. The Kernel method is used to solve the functional equation that arises in the polymer force problem. Finally, the Transfer Matrix method is used to solve a problem in colloid dispersions. All these methods are combinatorially similar as they all construct equations by considering the action of adding an additional column to the set of objects.     

Gas-phase optrode measurements of oxygen in calorimetric vessels

Simultaneous measurements of oxygen and heat rates are useful for the determination of thermodynamics and kinetics of metabolic and chemical reactions involving oxygen. Optrodes have not previously been used to measure oxygen inside calorimetric vessels. The optrode used in this study produces <2 μW and can be used to make measurements in both gaseous and aqueous systems. An external syringe injection of air was used to calibrate the optrode, and zinc–air batteries were used to evaluate the system. Data on maple leaf buds were collected to demonstrate application to respiration measurements.     

Compilation of an ESI-MS Library of β-Lactam Antibiotics for Rapid Identification of Drugs

β-Lactam antibiotics are among the most frequently used in clinical therapy. Thirty-three cephalosporin and eleven penicillin antibiotics frequently used in China have been used to create an ESI-MS library. A single-quadrupole mass analyzer was used for rapid identification. The product ions of these 44 β-lactam antibiotics were assigned to establish the fragmentation patterns and a standard ESI-MS library was established. Along with the specificity that product ion spectral information provides, the library provides another means to help identify β-lactam antibiotics. This is an important complement to the retention time from LC separations, and a valuable tool for confirming the identity of counterfeit drugs.     

On the understanding of the results of NMR spectra prediction using spectroscopic databases

Using spectroscopic databases for spectra prediction has become popular. Although most of the shifts predicted may be used as displayed there are some practical limitations. Some of these are suitable to distort results that are used without further consideration. Reasons and consequences of the most common aspects in this respect are discussed throughout this paper. Most critical effects are expected to rise from the presence of unrecognised data gaps and violation of the conventions used for structure coding for the database used. Any high standard deviation of predicted shift values or wide range of shift distributions indicate the need of further investigation. Looking up the reference data for the focus atom concerned can easily clarify most situations.     

Thermogravimetric Study of Volatile Precursors For Chemical Thin Film Deposition. Estimation of vapor pressures and source temperatures

Normal pressure thermogravimetry (TG) measurements were used to study the sublimation behavior of several volatile metal compounds, used as metal precursors in thin film fabrication by chemical vapor phase methods, like atomic layer deposition (ALD) and chemical vapor deposition (CVD). The results indicated that dynamic TG measurements may be used to find correct source temperatures to be used in an ALD reactor: a good correlation between the source temperatures used in ALD and temperatures corresponding to mass losses of 10 and 50% in TG was verified. It was also found that isothermal TG measurements offer a simple way for the vapor pressure measurements which otherwise are not trivial for solids with only moderate volatility. This revised version was published online in July 2006 with corrections to the Cover Date.     

汽车排放污染物的共振增强多光子电离光谱分析

汽车排放的主要污染物为CO,HC,NOx(x=1,2）,SO2,Pb,苯丙芘,固体颗粒等[1],其尾气的检测对维护人类自身健康具有十分重要的意义．共振增强多光子电离光谱（Resonant Enhanced Multi-Photonionization,REMPI）是一种超灵敏光谱检测技术,它的灵敏度比LIF（Laser InducedFluorescence）还要高．1979年,Brophy和Rentttner[2]提出了REMPI可以作为检测大气污染的方法．后来,不同的研究小组采用了不同的REMPI方案对大气污染类分子进行了测量研究［3-6]．由于采用可调谐染料激光器为光源,可以使用同一种染料对几种具有相近特征波长的分子进行同时测定．本文报     

化学废旧电池的环境污染和利用

本文就化学电池的种类、废旧电池的危害、电池工业的发展方向、国内外废旧电池的再生和利用情况进行了讨论,并对我国废旧电池的回收提出一些合理的建议。     

双波长光度法配合物组成和稳定常数的测定

利用双波长光度法的选择性这一特点，消除体系中有关物种的干扰，直接测定配体的平衡浓度，基于此结合溶液中物种的分布系数，建立了测定配合物组成和稳定常数的方法，手续简便可靠，试用于Ｃｕ（Ⅱ）－５－Ｂｒ－ＰＡＤＡＰ体系获得了满意的结果。