(R)-4-氰基-3-羟基丁酸乙酯的合成

研究了一条新的路线用于他汀类药物的重要中间体(R)-4-氰基-3-羟基丁酸乙酯的合成. 以廉价、易得的L-(－)-苹果酸为起始原料, 经酯化、还原、溴代和氰化四步反应得到目标化合物(R)-4-氰基-3-羟基丁酸乙酯, 合成总收率为56.7%. 所有中间体和最终产物均由ESI-MS, 1H NMR和13C NMR光谱及比旋光度表征并与文献值比较. 该方法原料易得、操作简便、收率良好, 产物容易分离纯化, 是一条适合大规模制备(R)-4-氰基-3-羟基丁酸乙酯的新合成工艺路线.     

Total Synthesis of 3 (R)-Panaxynol

Panaxynol1,asacommonconstituentofmanyplantparts',wasfirstdescribedbyTakahashietal.2in1964asaconstituentofPanaxyginseng.C.A.MeyershowedinhisBioassayshowedthatpanaxynolhadselectiveinvitrocytotoxicityagainstL-1210',MKI,B-16,andL-929cancercelllinescomparedtonormalcellcultures4.TheabsoluteconfigurationhadbeenestablishedbyLarsenetal.5tobe3R.Hereinwereportthefirsttotalstereoselectivesynthesisofpanaxynol(l).C'-CIafragmentofpanaxynol1wasobtainedaccordingtothefollowingsequencefReagentsandconditio…     

(S)-2-乙氧基-3-(4-羟基苯基)丙酸乙酯的合成

(S)-2-乙氧基-3-(4-羟基苯基)丙酸乙酯的合成;二乙氧基乙酸乙酯;Horner Wadswordth Emmons反应;催化氢化;化学拆分;（S） 乙氧基（羟基苯基）     

Efficient Synthesis and Practical Resolution of 1-(Naphthalen-1-yl)ethanamine,a Key Intermediate for Cinacalcet

An efficient synthesis of 1-(naphthalen-1-yl)ethanamine ( RS -2) and its practical resolution to optically pure (1R)-(naphthalen-1-yl)ethanamine ( R -(+)-2), a key intermediate in the synthesis of cinacalcet hydrochloride (1), is described. The resolution of RS -2 using R-(?)-mandelic acid as a resolving agent in ethanol was established on an industrial scale to give pure R -(+)-2 with >99.8% ee after liberation of the amine from its mandelate salt. An efficient process for the racemization of undesired isomer S -(?)-2 is also provided to maximize the yield of desired enantiomer.     

IMMOBILIZATION OF Saccharomyces Cerevisiae USING POLY（ACRYLAMIDE） GEL FOR ASYMMETRIC SYNTHESIS OF R（-）-MANDELIC ACID

In this paper, the poly(acrylamide) hydrogel used to immobilize saccharomyces cerevisiae for asymmetric synthesis of R(-)-mandelic acid was prepared with free radical ploymerization in deionized water at room temperature under nitrogen atmosphere. The influence of the composition of hydrogel, loading amount of cells and culture conditions on the asymmetric synthesis was investigated. Results show that PAAm hydrogel is a feasible carrier for immobilization of cells which is a potential alternative method to prepare enantiomerically pure R(-)-mandelic acid.     

IMMOBILIZATION OF Saccharomyces Cerevisiae USING POLY(ACRYLAMIDE)GEL FOR ASYMMETRIC SYNTHESIS OF R(-)-MANDELIC ACID

1. INTRODUCTIONPoly(acrylamide) hydrogel (PAAm gel), which is able to swell, but cannot be dissolved in the aqueous environment, is a three-dimension network with repeating hydrophilic units -CONH2. Since PAAm gel has a good biocompatibility as well as a high mechanical strength, and can be easily separated from reaction medium, PAAm gel has often been employed to immobilize enzymes and cells so as to catalyze various of chemical and biochemical reactions [1,2]. So far, biosynthesis …     

Thermoanalytical Study of O,O'-dibenzoyl-(2R, 3R)-Tartaric Acid SMC

A non-isothermal experimental study using thermogravimetry (TG) and differential scanning calorimetry (DSC) was conducted for investigation the oxidation reactivity of natural phosphate and its demineralised products. The analyses were carried out in oxygen atmosphere and at different heating rate (5, 10, 20, 30, 50, 60°C min^-1) up to 1000°C. The results indicated that the material washed with HCl from the original phosphate, mainly apatite and carbonates of calcium and magnesium, as well as with HCl/HF, silicates minreals, had an inhibition effect during oxidation reactions of organic material. The increase of the heating rate shifted the reactions to higher temperatures. In addition, kinetic parameters were determined by assuming a single first-order kinetic model, using the Coats-Redfern method. The influences of demineralization process of natural phosphate and the heating rate were examined and discussed. This revised version was published online in August 2006 with corrections to the Cover Date.     

O,O'-Di-p-toluoyl-(2R,3R)-tartaric acid as supramolecular resolving agent

O,O'-di-p-toluoyl-(2R,3R)-tartaric acid (DPTTA) was investigated as supramolecular complex (SMC) forming resolving agent with three racemic alcohols (menthol, 4-methyl-2-pentanol, trans-2-iodo-cyclohexanol) by preparative scale experiments and thermoanalytical measurements. Despite the very small structural difference (two methyl groups) between the O,O'-dibenzoyl-(2R,3R)-tartaric acid (DBTA) and DPTTA, their SMC forming properties with water and racemic alcohols is very different. While DBTA forms SMC with all the three investigated alcohols, DPTTA forms SMC only with trans-2-iodo-cyclohexanol. DPTTA binds the guest compound less strongly and the stoichiometry of the SMC is also different. The weaker interactions resulted in less effective optical resolutions. The results of these investigations remind us, that in optical resolutions during the chiral discrimination process the weaker interactions have a determining role, since DBTA and DPTTA have the possibility to form the same strong (O-H···O and N-H···O) hydrogen bond network. This revised version was published online in August 2006 with corrections to the Cover Date.     

Synthesis of the Juvenoid (S)-(+)-Hydroprene from L-(-)-Menthol

The versatile chiral synthon methyl (R)-5,5-dimethoxy-3-methylpentanoate has been prepared for the first time via ozonolytic decyclization of (R)-4-menthenone, which is available from L-(-)-menthol. The optically pure juvenoid (S)-(+)-hydroprene can be prepared from the synthon     

重组大肠杆菌细胞不对称还原4-氯乙酰乙酸乙酯合成(R)-(+)-4-氯-3-羟基丁酸乙酯

 从赭色掷孢酵母(Sporobolomyces salmonicolor ZJU0105)中克隆出NADPH依赖型醛基还原酶基因,构建了重组大肠杆菌E.coli BL21(pET28-ALR0105), 该工程菌可以高效地表达醛基还原酶. 将重组细胞用于催化4-氯乙酰乙酸乙酯不对称还原,合成出具有光学活性的(R)-(+)-4-氯-3-羟基丁酸乙酯. 实验发现,在加入适量辅酶及辅酶再生酶的条件下,利用重组细胞催化还原反应可以获得比使用赭色掷孢酵母更高的转化率、产率和ee值,得到了几乎是光学纯的(R)-(+)-型产物,从而解决了酵母细胞催化此类反应ee值较低的问题. 考察了辅酶及共底物的添加、底物和产物的浓度、pH值、温度以及菌体密度等因素对还原反应的影响. 结果表明,不对称还原反应必须在辅酶NADPH和辅酶再生酶系及共底物葡萄糖的参与下进行; 底物和高浓度的产物对还原反应有一定的抑制作用; 当pH＞6.0时,反应的转化率及产率都显著降低; 高密度重组细胞可以减小底物的抑制作用.     

A NEW OPTICALLY ACTIVE POLYURETHANE DERIVED FROM CHIRAL(2R, 3R)(+)-DIETHYL L-TARTRATE AND DIISOCYANATE*

Optically active polyurethane was synthesized by the polyaddition of (2R, 3R)-(+)-diethyl L-tartrate (DET), 4,4'-diphenylmethane diisocyanate (MDI) and polyethylene glycol (PEG) with variousmolecular weights at 60℃in DMSO. The polymers were characterized by specific rotation, DSC and ~1HNMR spectra.     

Synthesis of (3S,4R)-bengamide E

（3S,4R）-Bengamide E（2） was synthesized starting from D-glucono-δ-lactone（3） and the key deoxygenation step from 13 to 15 was achieved by the application of NaBH₃CN and ZnI₂.Compared with natural bengamide E（1）,the synthetic compound（35,4R）-bengamide E（2） was inactive against the cell growth of HUVEC and cancer cells.These data represent the significance of the stereochemistry at C-3 and C-4 of bengamides for structural recognition and binding with the target（s）.     

(R)-2-羟基-4-苯基丁酸乙酯的合成

综述了血管紧张素转化酶抑制剂类治疗高血压和充血性心力衰竭药物的关键中间体（R）－2－羟基－4－苯基丁酸乙酯的合成方法。参考文献25篇。     

（2S,3R）—谷象虫聚集信息素的合成

（２Ｓ，３Ｒ）┐谷象虫聚集信息素的合成黄锦霞＊李焰马兴泉陈祖兴徐章煌（湖北大学化学系武汉４３００６２）关键词（２Ｓ，３Ｒ）－谷象虫聚集信息素，合成，不对称顺式醇醛缩合反应，Ｎ－莰烷－磺内酰胺１９９７－０７－１４收稿，１９９７－０９－２９修回湖北省自然...     

Asymmetric Synthesis of (R)-and (S)-Moprolol

A simple and effective procedure for the enantioselective synthesis of (R)-and (S)-moprolol was described.The key step was the asymmetric synthesis of enantiopure (R)-and (S)-guaifenesin,which were synthesized from enantioenriched (R)-3-chloro-1,2-propanediol and (S)-epichlorohydrin via kinetics of hydrolysis resolution of racemic epichlorohydrin by chiral Salen-CoIIII complex.The e.e.values of both the optical compounds were above 98%,and the chemical structures of the target compounds were confirmed by 1H NMR,13C NMR,IR,and MS.     

Rapid and Efficient Synthesis of (R)-Aryloxypropionic Acid Esters Under Microwave Irradiation

A series of (R)-(+)-ethyl aryloxypropionates (4a–4p) have been synthesized by the reaction of substituted phenols with ethyl (S)-(?)-tosyloxy lactate under the conditions of microwave irradiation and without solvents. The reaction conditions have been optimized. A good method for the preparation of (R)-(+)-ethyl aryloxypropionate was developed, with good yields, high enantiomer excess, short reaction times, easy workup, and simple procedure.     

除草剂中间体R-(+)-2-(4-羟基苯氧基)丙酸酯的不对称合成

报道了一种合成苯氧丙酸类除草剂重要中间体R－（＋）－2－（4－羟基苯氧基）丙酸乙酯（即R－（＋）－HPE）的方法，以L－乳酸为起始原料，先经酯化合成L－乳酸乙酯，再与对甲苯磺酰氯反应制备L－对甲苯磺酰乳酸乙酯，再与对苯二酚综合获得R－（＋）－2－HPE，产品的总收率为72.1%。通过元素分析和红外光谱测定，确定了所合成的R－（＋）－HPE的化学结构和纯度；由旋光度的测定，确定了所合成的R－（＋）－HPE的光学纯度为95.7%。     

(R)-2-硫代四氢噻唑-4-羧酸及其酯的合成

L-半胱氨酸盐酸盐与二硫化碳, 氢氧化钠在硝酸铅存在下进行成环反应得到(R)-四氢噻唑-2-硫酮-4-羧酸产率76% , 后者与 醇在硫酸铁水合物催化下反应得到(R)-四氢噻唑-2-硫酮-4-羧酸酯, 产率40～82% .     

CTAB透性化酵母细胞生物催化合成(S)-(+)-3-羟基丁酸乙酯

 利用十六烷基三甲基溴化铵(CTAB)透性化啤酒酵母细胞中高活性的脱氢酶,借助于辅助底物乙醇和葡萄糖,对3-羰基丁酸乙酯(EOB)不对称还原合成(S)-(+)-3-羟基丁酸乙酯((S)-(+)-3-EHB)进行了研究. 结果表明,CTAB透性化酵母细胞中的醇脱氢酶和6-磷酸葡萄糖脱氢酶的活性分别比未经处理的酵母细胞高482倍和6.5倍. 在相同条件下,CTAB透性化细胞对EOB的还原比未经处理的酵母细胞快. 细胞浓度对反应有明显影响,当透性化酵母细胞浓度＜90 mg/ml时,(S)-(+)-3-EHB的产率和对映体过量值都较低; 当酵母细胞浓度≥90 mg/ml,在最佳进料速率、最适温度和pH条件下,振摇速度为125 r/min时, (S)-(+)-3-EHB的浓度达到最大值314 mmol/L. 在反应开始的6 h内,(S)-(+)-3-EHB的产率可达94%,对映体过量值≥98%,但24 h后产率和对映体过量值分别降低到85%和91%.     

Asymmetric Synthesis of (R)-Fluoxetine: A Practical Approach Using Recyclable and in-situ Generated Oxazaborolidine Catalyst

A practical route for the synthesis of (R)-fluoxetine•HCl (ee＝96%) in 56% overall yield was described. The key intermediate (R)-3-chloro-1-phenyl-1-propanol was obtained by the asymmetric reduction of prochiral 3-chloropropiophenone using in-situ generated oxazaborolidine catalyst derived from (S)-α,α-diphenylprolinol. The chiral procatalyst (S)-α,α-diphenylprolinol was recovered quantitatively and recycled. An improved practical synthesis of (S)-α,α-diphenylprolinol was also discussed.