Stereoselective Synthesis of α-Aminonitril on Glucose Templates

Both proteinogenic and non proteinogenic α-amino acids are of particular interest as constituents of peptide factors, peptidomimetics and antibiotics for the construction of modern selective drugs. [1] Furthemore, α-amino acid derivatives are interesting building units for chiral-pool syntheses of enantiomerically pure natural products. [2] Numerous efforts in modern organic synthesis are centered on the synthesis of enantiomerically pure α-amino acids. [3] During the past three decades efficient methods of asymmetric synthesis of α-amino acids have been developed; most of them are based on electrophilic transformations of organometallic intermediates. [4] Using the concept that the chirality of the carbohydrates can be exploited for diastereoselective reactions, Kunz and his cooperator had developed a Strecker synthesis with glycosyl amines as chiral auxiliaries. [5]     

酚醛型氰酸酯与双酚A型环氧共固化反应的FTIR研究

在恒温固化条件下,通过FTIR跟踪方法,研究了酚醛型氰酸酯与双酚A型环氧共固化反应的路径及其反应机理.共固化体系的反应过程包括在150℃及其以下温度,主要发生的是氰酸酯的三嗪环化固化反应,其中三嗪环化固化反应由于环氧的加入,反应速率被极大地提高了;同时,酚醛型氰酸酯中的氨基甲酸酯类杂质与环氧发生开环聚合反应,引起环氧官能团产生弱而持续的消耗.但在此阶段,酚醛型氰酸酯与环氧之间没有化学反应发生;在180℃及其以上温度,三嗪环和环氧发生反应,异构为异氰脲酸环结构,并进一步反应生成唑啉酮环结构,由于该反应的发生,促进了环氧官能团的消耗速度,在环氧官能团的转化率-时间图中,出现倒S曲线;在三嗪环的转化率图中,出现一个极大值后再降落的曲线.反应温度的提高有利于促进酚醛型氰酸酯与环氧之间的共固化反应,特别是当反应温度为220℃时,氰酸酯官能团和环氧官能团的消耗、三嗪环和唑啉酮环的生成均以较快的速率进行,—OCN生成三嗪环的转化率可以较容易地达到1,而唑啉酮环的转化率不超过0.5.     

聚合物支载合成杂环化合物的研究进展

聚合物支载的反应与传统的经典液相反应相比，具有独特的优点，广泛应用于 杂环化合物的合成。综述了近年来杂环化合物的固相和液相合成研究。     

用Reichardt''''s Dye研究碳酸酯溶剂极性的经验参数ET(30)

使用2,6-二苯基-4-(2,4,6-三苯基-1-吡啶鎓)苯氧内盐染料(Reichardt's Dye)研究锂离子电池中非水电解质溶剂碳酸酯的极性,并测量极性经验参数ET(30)碳酸乙烯酯为48.6,碳酸丙烯酯为46.1,2,3-碳酸丁烯酯为45.7,碳酸二甲酯为39.0,碳酸甲乙酯为37.3,碳酸二乙酯为37.0.LiClO4加入到碳酸酯溶剂中,显色剂受到离子的盐效应影响,表现为溶液体系的ET(30)值增加,极性增大.由于溶液中粒子间的相互作用不同,环碳酸酯与链状碳酸酯极性变化趋势不同.极性大的溶剂易形成Ar-O-…solvent…Li+结构,起到缓冲作用,抑制了显色剂的酚氧基与Li+直接作用.     

从月桂烯合成梨圆蚧性信息素

梨圆蚧是对果林危害较大的害虫。该虫的性信息素包括三个组分:3-亚甲基-7-甲基-7-辛烯-1-醇丙酸酯(1)、(2Z)-3,7-二甲基-2,7-辛二烯-1-醇丙酸酯(2)和(2E)-3,7-二甲基-2,7-辛二烯-1-醇丙酸酯(3)。本文介绍了通过对月桂烯进行结构改造来合成梨圆蚧性信息素,从月桂烯到1,总产率为19%。工业上从月桂烯制龋萑花醇和香叶醇,再将橙花醇和香叶醇转变为相应的氯烯醇后再还原、丙酰化即得2和3,其总产率分别为30%和28%。(以橙花醇和香叶醇计)。月桂烯可从β-蒎烯裂解而得。我国有丰富的蒎烯资源,所以开辟从月桂烯合成梨圆蚧性信息素的新途径具有重要的意义。     

离子型溶液聚合化工操作的程序设计

离子型溶液聚合速度方程式一般可写成: r=-dM/dθ=kM~mC~n式中M,C分别代表溶液中单体与催化剂的浓度,m,n是两个动力学参数。为了控制聚合过程或设计适当的反应器,必须考虑体系的动力学特性与传热特性的紧密联系。本文 对恒温下分批式聚合操作的各种实施方案进行了讨论。     

乙酰基硫代甲酰芳胺合成二氢吡嗪的研究

报道了一种合成乙酰基硫代甲酰芳胺的方法. 合成的乙酰基硫代甲酰芳胺与1,2-乙二胺缩合生成5-(4'-取代苯胺基)-6-甲基-2,3-二氢吡嗪类杂环化合物.     

ＳRN 1 反应及某些SET引发的链式反应的新进展

本文综述了近几年来 S_(RN)1反应及某些 SET 引发的链式反应的研宄进展。包括四方面,即有机杂环化合物的 S_(RN)1反应;在 S_(RN)1反应中作为亲核试剂的各种有机负离子;金属离子对 S_(RN)1反应的催化作用以及 S_(RN)1在合成应用方面的进展。     

Syntheses, Structures and Characterizations of Two New Vanadium(V) Complexes: [PyH][VⅤO2(C14H9N2O3Br)] and [VⅤO(C14H9N2O3Br)(OCH3)]

The new oxovanadium (Ⅴ) complex, [PyH][VO2(L)] 1 (salicyladehyde 5-bromo salicyloylhydrazone is abbreviated as H2L; Hpy is protonated pyridine) was obtained from a refluxed solution of VOSO4 and H2L in acetonitrile-methanol-pyridine. Similarly, another new complex, [VO(L)(OCH3)] 2 was synthesized by refluxing VOSO4 and H2L in methanol-pyridine. Crystal data for 1: C19H15N3O5BrV, Mr = 496.2, monoclinic, P21/n, a = 7.1885(3), b = 9.2718(3), c = 28.803(1) (A), ( = 96.185(1)(, Z = 4 and V = 1908.6(1) (A)3; for 2: C15H12N2O5BrV, Mr = 431.1, monoclinic, P21/n, a = 12.202(2), b = 8.045(2), c = 16.604(3)(A), ( = 101.29(3)(, Z = 4 and V = 1598.4(2)(A)3. The structures of 1 and 2 have been determined by X-ray analyses and reveal that the coordination environments of V atoms in both complexes are of square-based pyramid. Three of the four based donor atoms are from the tridentate "ONO" donor ligand while the fourth is one terminal oxygen atom with the V(1)–O(3) distance 1.646(4) (A) for 1 and one -OCH3 group with the V(1)-O(3) distance 1.753(3)(A) for 2. The V(1)-O(4) terminals occupy the axial sites in both cases. The complexes are also characterized by IR and 1H NMR spectroscopies.     

Double Michael Addition Reaction of Bischalcone under Ultrasound

The Michael addition of 1,5-diaryl-1,4-pentadien-3-ones with active methylene compounds has been the subjects of many investigations. Ultrasound has increasingly been used in organic synthesis in the last three decades. Compared with traditional methods, this method is more convenient and easily controlled. A large number of organic reactions can be carried out in higher yield, shorter reaction time or milder conditions under ultrasonic irradiation. KF/Al2O3 as a useful solid supported catalyst has received considerable attention because of their high level of chemoselectivity and environmental compatibility as well as simplicity of operation and their ready availability at low cost. Herein we report the double Michael addition of dibenzalacetone with active methlene compounds such as dimethyl malonate, diethyl malonate,methyl cyanoacetate and ethyl cyanoacetate catalyzed by KF/Al2O3 under ultrasound irradiation.