(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.     

Convenient Synthesis of Bis（oxazoline） Dicarboxylate Derivatives

The synthesis of bis(oxazoline) dicarboxylate derivatives was investigated.Diethyl-aminosulfur trifluoride (DAST) was used as a convenient cyclization reagent in the synthesis of bis(oxazoline) dicarboxylate derivatives,which can not be obtained by the general method using MsC1 and Et3N as dehydrating cyclization reagent.     

Synthesis and Crystal Structure of aNovelPolythiotungstate Compound[PPh4]2[（S）2W（μ—S）2（O）W（THF）（μ—S）2W（S）2]

1 INTRODUCTION Polythiotungstate complexes can be prepared from the protonation of one sulfur atom of [WS4]2－ and subsequent intramolecular redox reactions[1,2]. For example, [(S)2W(m-S)2W(m-S)2W(S)2]2 was formed by the acidification of a diluted aqueous solution of (NH4)2[WS4] with dilute H2SO4[3]. When a diluted aqueous solution containing [WS4]2 was acidified with 0.1mol/L HCl, [(S)2W(m-S)2(O)- W(H2O)(m-S)2W(S)2]2 was formed[4]. [(S)2W- (m-S)2(S)W(m-S)2W(S)2]2 was form…     

A Convenient Synthesis of 6,8-Dimethoxy-3-[（2-（4-methoxyphenyl）ethyl）isocoumarin

6,8-Dimethoxy-3-[2-（4-methoxyphenyl）ethyl]isocoumarin was synthesized by condensation of 5,7-dimethoxyhompophthalic acid with 3-（4-methoxyphenyl）propanoyl chloride. The structure of the synthesized compound was confirmed by its mass spectrometric studies. The synthesized compound serves as a model for synthesis of DL-agrimonolide.     

Asymmetric Synthesis of （ － ）－（2R ,3R, 6S ）－Irnigaine

Asymmetric synthesis of irnigaine was achieved starting from an enantiopure β-amino ester 5 using the condensation of amino al-cohol 2 with acetylacetone and the subsequent intramolecular cycllzation as the key steps.     

Asymmetric Hydrogenation Synthesis of （S）-（＋）-2-（6＇-methoxyl-2-naphthyl） propionic Acid by Cinchona Modified Pd（0）-α-FeOOH Catalyst

Asymmetric hydrogenation of (6-methoxyl-2-naphthyl)-2-acrylic acid catalyzed by cinchona modified Pd(0)-α-FeOOH was reported and ee‘s of (S)-( )-2-(6‘-methoxyl-2-naphthyl)propionic acid ((S)-( )-naproxen) up to 98% was achieved firstly.     

A Novel Synthesis of （-）-10-epi-a-Cyperone

An alternative route for the synthesis of (-)-10-epi-ct-cyperone 1 starting from ( )-dihydrocarvone 2 is described by using an asymmetric Michael addition as a key step. The routefeatures more efficiently and can be performed in large scale.     

Study on the Stereoselective Synthesis of Carbapenem Sidechain （2S,4S）-4-Acetylsulphanyl-2- [（S）-l-phenylethylcarbamoyl]- pyrrolidine-l-carboxylic Acid 4-Nitrobenzyl Ester

A stereoselective and economic synthesis of the carbapenem sidechain (2S, 4S)-4-ace-tylsulphanyl-2- [ (S) 1-phenylethyl-carbamoyl] pyrrolidine-l-carboxylic acid 4-nitrobenzyl ester was developed. Due to the effect of spatial hindrance, only the (2S,4S) diastereomer 3 was obtained by coupling 1 and the inexpensive racemic 2 catalyzed by EEDQ.     

A Short and Stereoselective Synthesis of the （-）-（5R, 6S）-6-Acetoxy-hexadecane-5-olide

(-)-(5R, 6S)-6-Acetoxyhexadecan-5-olide 1, a natural mosquito attractant pheromone,was synthesized from readily available aldehyde 2 and cyclopentanone 3 using L-proline-catalyzed asymmetric aldol reaction as the key step.     

Synthesis and Crystal Structure of （2S,5S）-1-Aza-2-（2-pyridyl）-3-oxa-4,4-diphenylbicyclo [3.3.0] Octane

1 INTRODUCTION The catalytic asymmetric synthesis has been a challenging subject in organic synthesis. The deve- lopment of efficient enantioselective catalysts appli- cable to a wide range of carbon-carbon bond form- ing reactions represents a pivotal …     

An Enantioselective β-Lactam Synthesis Starting from L-(S)-Glyceraldehyde Acetonide

Complete diastereoselectivity is observed during the cyclocondensation of activated glycine derivatives with aldimines derived from L -(S)-glyceraldehyde acetonide. 3,4-cis-β-lactams are isolated in high optical and chemical yields. They are converted into key intermediates used in the syntheses of various mono- and bicyclic β-lactam antibiotics. A mechanism is suggested to explain this remarkable diastereoselectivity.     

(R)-甘油醛缩丙酮的合成及Wittig反应选择性

D-(R)-甘油醛缩丙酮是近年来研究的很多的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.用Lew is酸无水ZnC l2作为催化脱水剂,D-甘露醇与丙酮缩合反应合成二异亚丙基缩合物,然后用NaIO4氧化断键制备D-(R)-甘油醛缩丙酮,该方法具有产率高、价廉、环境友好等优点.主要研究了(R)-甘油醛缩丙酮W ittig反应的立体选择性.     

3-(吗啉吡啶基)-5-取代异噁唑类化合物的合成及抗菌活性研究

以6-氯-3-吡啶甲醛为原料, 通过多步反应合成了一系列3-(吗啉吡啶基)-5-取代异噁唑类化合物, 并用IR, 1H NMR, 13C NMR和MS进行了结构确证. 这些化合物均以异噁唑为母核, 具有近似的平面结构, 在异噁唑环的3-位引入吗啉吡啶基, 而在5-位引入酯基、取代氨基、三唑环和噁唑烷酮环. 研究了这些化合物对金黄色葡萄球菌、耐甲氧西林金黄色葡萄球菌、表皮葡萄球菌、粪肠球菌和大肠杆菌的抑制活性, 发现与噁唑烷酮类上市药物利奈唑胺相比, 目标化合物均显示出更低的抗菌活性, 最低抑制浓度(MIC)大于32 mg/L, 这些试验结果表明异噁唑母核的5-位缺乏sp3杂化结构, 可能会导致抗菌活性的显著降低.     

A Convenient and Stereospecific Synthesis of (Z)-Benzylidenephthalides

Several 3-benzylidenephthalides have been isolated from natural sources1-2. Some of them are known to possess useful biological activity1 and are also valuable intermediates3 for the synthesis of naturally occurring biologically active compound. Most of the natural 3-benzylidenephthalides exist in the (Z)-configuration. Synthe-tic methods for construction of a 3-benzylidene-phthalide skeleton have been developed4. Some of these methods for synthesizing highly oxygen-functionalized compound…     

Synthesis and Antibacterial Activity of New Cephalosporin Compounds

The fourth generation cephalosporin cefepime I exhibited potent antibacterial activity with board antibacterial spectrum1,2.Based on the structure of cefepime,we synthesized its analogs Ia having fluoro atom at the aminothiazolyl oxime moiety at the7-position of the cephem nucleus,and Ib possessing1-(2-fluoroethyl)pyrrolidium methyl group at the3-position.It was reported that cephalosporin derivatives with a quaternary ammonium moiety at the3-position of the cephem nucleus,showed enhanced ant…     

Synthesis and Antibacterial Activity of New Tetracyclic Triazolo-thiadiazino Fluoroquinolones

Since nalidixic acid1 was first clinically used as a potent antibacterial agent, many analogues, such as bicyclic ciprofloxacin2, tricyclic ofloxacin3, have become an important class of therapeutical compounds. Recently, novel tetracyclic fluoroquinolones having a thiazolooxazine ring with potent antibacterial activity against both G+ and G- have been reported4. In order to find better antibacterial agents for our urgent research of the multidrug resistant (MDR)5, we herein describe a facil…     

(S)-异丝氨酸的合成研究

以L -天冬氨酸为原料 ,经酯化、重氮化 -水解、氨解、Hofmann降解等反应合成了具有良好光学纯度的 (S) -异丝氨酸。总收率不低于35 %     

N-邻羟苄基氨基酸的合成、表征及抑菌活性

将水杨醛、溴代水杨醛及二溴代水杨醛分别与4种L-α-氨基酸进行缩合反应生成相应席夫碱,不经分离直接加硼氢化钠将其还原制得N-邻羟苄基氨基酸类化合物(3)。 化合物的结构经IR、¹H NMR和元素分析测试技术表征确认。 测得化合物3在质量分数为0.05%时,对金黄色葡萄球菌的抑菌率为100％,对白色念珠菌有较强的抑菌活性,对大肠杆菌有一定的抑菌活性。 氨基酸的碳链R的结构是影响化合物抑菌活性的关键因素,不同烷基R对白色念珠菌和大肠杆菌抑菌活性增强的顺序为CH(CH₃)₂＞CH₃,CH₂CH(CH₃)₂＞H,苯环上引入溴原子对目标化合物的抑菌活性影响不明显。     

Cu（Ⅱ）—Ln（Ⅲ）双核配合物的合成,磁性和抗菌活性

合成和表征了６种以草酰胺为桥联的异双核配合物Ｃｕ（ｏｘｅｎ）Ｌｎ（ｐｈｅｎ）２（ＣｌＯ４）３（ｏｘｅｎ代表Ｎ，Ｎ－双（２－氨乙基）草酰胺根阴离子；ｐｈｅｎ为１，１０－邻菲咯啉；Ｌｎ表示Ｙ，Ｌａ，Ｃｅ，Ｎｄ，Ｇｄ和Ｙｂ）测定了Ｃｕ（ｏｘｅｎ）Ｇｄ（ｐｈｅｎ）２（ＣｌＯ４）３．Ｈ２Ｏ的变温磁化率（４－３００Ｋ），并用最小二乘法和从自旋Ｈａｍｉｌｔｏｎｉａｎ算符Ｈ＝－２ＪＳ１。Ｓ２导出的磁方程拟合，求得     

由(S)-和( R )-天冬氨酸合成( R )-和(S)-(2-苄氧乙基)环氧乙烷的改良方法

苄氧乙基环氧乙烷;不对称合成;由(S)-和( R )-天冬氨酸合成( R )-和(S)-(2-苄氧乙基)环氧乙烷的改良方法