Study of photopolymers. XVI. Novel syntheses of the polymers with azidonitrobenzoyl groups and their photochemical and thermochemical reactions

Poly-2-(2-azido-5-nitrobenzoyloxy)ethylmethacrylate (P-II-A) and poly-2-(4-azido-3-nitrobenzoyloxy)ethylmethacrylate (P-II-B) were synthesized from the reactions of 2-hydroxyethylmethacrylate with 2-chloro-5-nitrobenzoic acid and 4-chloro-3-nitrobenzoic acid, respectively, by substitution reactions of sodium azide with the corresponding chloronitrobenzoyl group. In addition, the degradation reaction of the 2-azido-5-nitrobenzoyl group in P-II-A and the transformation of the 4-azido-3-nitrobenzoyl group to 5-carboxylbenzofurazane-1-oxide ring in P-II-B by irradiation with ultraviolet (UV) light or by heating were investigated in detail. In the photochemical reaction the reaction of the azide group in P-II-A was affected by the presence of a spacer in the polymer chain. Moreover, in the thermochemical reaction the rates of the reactions of azide groups in P-II-A and P-II-B were controlled by the facility of molecular motion and the conformation of polymer chains.     

多孔有机含BINAP聚合物负载Rh催化剂在苯乙烯不对称氢甲酰化中的应用:柔性手性口袋对产物对映体选择性的提高作用

不对称氢甲酰化是合成具有单一光学活性物质(如光学活性的醛、α-氨基酸和醇等)最为重要的反应之一.尽管不对称氢甲酰化反应的研究超过40年,但仍然是催化体系中具有挑战性的课题.该反应涉及到产物的化学选择性、立体选择性和对映体选择性的优化.目前,在Rh催化体系中,使用磷-亚磷酸酯手性配体或双亚磷酸酯配体可以在不对称氢甲酰化反应中取得优异的催化性能.然而在Rh/手性双膦配体催化体系中,不对称氢甲酰化反应性能通常很低.以BINAP配体为例,负载Rh金属后,在催化苯乙烯不对称氢甲酰化反应中,产物的ee值只有25％.同时,由于均相催化体系存在催化剂回收和产物提纯等问题,因此有必要研究多相不对称氢甲酰化反应催化剂.本文使用乙烯基修饰的BINAP配体5,5'-divinyl-BINAP与具有不同结构的共聚单体二乙烯基苯或1,3,5-三乙烯基苯基苯共聚,得到具有不同孔结构的聚合物Poly-1和Poly-2.为了比较,利用线性共聚单体乙二醇二甲基丙烯酸甲酯与乙烯基BINAP共聚得到聚合物Poly-3.上述三种聚合物材料负载金属Rh后,用作苯乙烯不对称氢甲酰化反应的催化剂.固体13C核磁分析表明,三种聚合物材料负载金属后仍然保持较为稳定的C骨架结构.通过31p核磁可以看到,嵌入在材料骨架中的BIANP仍然保持未被氧化的状态.N2物理吸附结果发现Poly-1和Poly-2具有较大的比表面积和孔体积,而Poly-3的比表面积最小.热重分析显示,这些材料具有较高的热稳定性.在不同反应溶剂中催化剂活性差异较大.通过优化反应温度和合成气压力后,催化剂Rh/Poly-1在80℃和0.2 MPa下产物的对映体选择性可高达58.9％,支链醛与直链醛的比值为8.5;而在相同反应条件下,均相催化剂Rh-BINAP的ee值仅为35.3％,但高于Rh/Poly-3.这是由于三个多相催化剂骨架中BINAP周围环境不同所致.前两个催化剂中,BINAP与空间位阻较大的单体相连接,使得反应底物按照特定方向与催化活性位点接触,形成了类似于手性口袋的结构.而Rh/Poly-3中,BIANP周围是线性的共聚单体,不能形成有效的手性口袋结构.Rh/Poly-1重复使用7次后,催化活性没有显著下降.拓展X射线吸收精细结构表征结果表明,Rh/Poly-1催化剂使用前没有Rh-Rh键存在,但经重复使用后,Rh金属部分聚集,生成了Rh-Rh键.球差电镜照片也证实了这一点.     

Efficient syntheses and ring-opening reactions of trans- and cis-oxazoline-5-carboxylates

[formula: see text] cis- and trans-Oxazoline-5-carboxylates were synthesized efficiently from isopropyl trans-cinnamate utilizing the Sharpless AA reaction. trans-Oxazoline was much more reactive than the cis-isomer toward ring opening reactions. From ab initio molecular calculations, the cis-isomer was predicted to be less reactive than the trans-isomer by 2.7 kcal/mol. Both syn and anti acetylthio esters and anti diamino esters were synthesized from these cis- and trans-oxazoline-5-carboxylates.     

聚对苯二甲酸双酚丙烷酯的合成

聚酯的研究虽然早在1928年Carothers已开始进行,但是直到1941年Whinfield和Dickson发现聚对苯二甲酸乙二醇酯——涤纶——以后,才引起广泛的兴趣。由于大分子链中合有苯环,使绦纶具有高熔点和高结晶性,因而是一种优良的成纤材料。 如果继续增加主链中的苯环,可能得到热稳定性更高的高分子材料。本文郎报告聚对苯二甲酸双酚丙烷酯(Ⅰ)的合成和它的一些性能。KoptuaK等和Conix都会提到     

Solvent extraction of silver and thallium picrates with poly- and bis-(crown ether)s

Summary Solvent extraction of silver and thallium picrates by new poly- and bis(crown ether)s, which contain benzo-15-crown-5 or benzo-18-crown-6 moieties, was carried out in water-chloroform system. The poly- and bis(crown ether)s showed higher extractability for both metals than the corresponding monocyclic crown ethers.Especially poly- and bis(benzo-15-crown-5) were found to be quite effective extracting agents for Tl⁺.The extraction equilibrium constants and the complexation constants for the chloroform phase were also estimated.

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Lösungsmittelextraktion von Silber- und Thalliumpikraten mit Poly- und Bis-Kronenethern

Zusammenfassung Die Extraktion der Pikrate wurde in Wasser/Chloroform mit neuen Poly- und Bis-Kronenethern durchgeführt, die Benzo-15-Krone-5- oder Benzo-18-krone-6-Komponenten enthielten. Die Poly- und Bis-Kronenether wiesen für beide Metalle eine bessere Extrahierbarkeit auf als die entsprechenden monocyclischen Kronenether. Insbesondere Poly- und Bis(benzo-15-krone-5) erwiesen sich als wirkungsvolle Extraktionsmittel für Thallium(I). Die Extraktions-Gleichgewichtskonstanten und die Komplexbildungskonstanten für die Chloroformphase wurden bestimmt.

     

Syntheses of 4-(1-alkynyl)-2(5H)-furanones and coumarins via the palladium catalyzed cross-coupling reactions of potassium alkynyltrifluoroborates

An efficient synthesis of 4-(1-alkynyl)-2(5H)-furanones has been developed utilizing a palladium catalyzed coupling reaction of β-tetronic acid bromide with potassium alkynyltrifluoroborates in the absence of base. 4-Alkynylcoumarins were also synthesized using this method. The reactions are straightforward and the yields are excellent.     

Der Einfluss von D-Aminosäureresten auf das konformative Verhalten von Kollagenmodellpeptiden

The influence of D -amino acid residues upon the conformative behaviour of collagen model peptides. (L -Pro-L -Pro-Gly)₁₀ and (L -Pro-D (L )-Pro-Gly)₁₀ with 10 percent D -Prolin residues have been synthesized by the Merrifield technique. Further Poly-(Gly-Pro-Pro) and Poly-(Ala-Gly-Pro) with various amounts of D -amino acid residues have been synthesized by polycondensation of the proper tripeptides. The conformational behaviour of all these polypeptides has been studied by measurements at varying temperatures of optical rotation, circular dichroism and molecular weight. The results show that limited amounts of D -amino acid residues do not impedecollagen-like triple helical conformations. The denaturation temperatures, however, are considerably lowered by D -amino acid residues. The implications of these findings for the understanding of the properties of partially racemized degraded gelatins with relatively low gel melting points are discussed.     

The effect of fluorine atoms on gas transport properties of new polynorbornene dicarboximides

The new N-4-trifluoromethylphenyl-norbornene-5,6-dicarboximide (2a) and N-3,5-bis(trifluoromethyl)phenyl-norbornene-5,6-dicarboximide (2b) mixtures of exo and endo monomers were synthesized and polymerized via ring opening metathesis polymerization (ROMP) using bis(tricyclohexylphosphine) benzylidene ruthenium(IV) dichloride (I) and tricyclohexylphosphine [1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene][benzylidene] ruthenium dichloride (II) to produce the corresponding polynorbornene dicarboximides Poly-2a and Poly-2b, respectively. The transport of five gases He, N₂, O₂, CO₂ and CH₄ across membranes prepared from Poly-2a was determined at 35 °C using a constant volume permeation cell. The gas transport properties of the fluorine containing polymer Poly-2a were compared with those found for membranes from non-fluorinated poly(N-phenyl-exo-endo-norbornene-5,6-dicarboximide) (P-PhNDI). Gas permeability, diffusion and solubility coefficients of the fluorine containing polynorbornene Poly-2a were up to an order of magnitude larger than those of the non-fluorinated one. Poly-2a was found to have one of the largest gas transport coefficients reported to date in glassy polynorbornene dicarboximides.     

PAMPSLi/P(MMA-VAc)为基体的聚合物电解质

将聚(2-丙烯酰胺-2-甲基丙磺酸锂)(PAMPSLi)和聚(甲基丙烯酸甲酯-醋酸乙烯酯)[P(MMA-VAc)]与LiClO₄共混, 制备了复合聚合物电解质膜. 用FTIR, TG, XRD, DMA, SEM及电化学交流阻抗和机械性能测试对聚合物及其电解质膜的结构和性能进行了表征. 结果表明, PAMPSLi与P(MMA-VAc)共混后结晶状态发生变化, 交联网络变得密实, 提高了热稳定性和拉伸强度, 聚合物电解质膜含有较多微孔结构, 孔径为5~10 μm; 在20 ℃时, 当n(MMA)∶n(VAc)=2∶8, m(PAMPSLi)∶m[P(MMA-VAc)]=5∶95, m(LiClO₄)∶m(copolymer)=15∶85时, 聚合物电解质膜电导率可达到1.68×10^-3 S/cm, 且电导率未出现随LiClO₄含量的进一步增加而下降的现象. 将此电解质用于全固态电致变色显示器件表现出了优良的性能. 对加入PAMPSLi后聚合物电解质膜电导率和热稳定性提高的原因进行了初步探讨.     

Cycloaddition of oxetanes with heterocumulenes catalyzed by organotin iodide-lewis base complex

A series of 2-oxazinones 1-8 were synthesized from the cycloaddition reactions of oxetanes with isocya-nates by utilizing the complex of diphenyltin diiodide with hexamethylphosphoric triamide (HMPA) as a catalyst. Moreover, the reactions with carbodiimides proceeded under milder conditions with the same catalyst system, and gave 2-iminooxazines, 9 and 10 , in high yields.     

Liquid‐phase synthesis of mixture‐based bicyclic β‐lactam libraries

Five sets of 27‐membered combinatorial libraries of alicyclic β‐lactams were prepared via liquid‐phase Ugi 4‐center 3‐component reactions (U‐4C‐3CR) utilizing 3 different cis β‐amino acids, 3 different isonitriles and 5×3 sets of aldehydes. Through combinations of the building blocks of one of these libraries, all of the possible sublibraries were also generated. A few azetidinone derivatives were synthesized individually by parallel synthesis.     

Anionic templating: synthesis,structure, and characterization of novel three-dimensional mixed-metal oxychlorides Te(4)M(3)O(15).Cl (M = Nb(5+) or Ta(5+))

Two new three-dimensional oxychlorides are reported, Te(4)M(3)O(15).Cl (M = Nb(5+) or Ta(5+)). The isostructural materials were synthesized by chemical transport reactions utilizing TeO(2), M(2)O(5), and MCl(5) (M = Nb(5+) or Ta(5+)) as reagents. The compounds exhibit a three-dimensional cationic tunnel framework, with Cl(-) anions occupying the tunnels. Crystal data: monoclinic, space group C2/c, a = 18.9944(7) A, b = 7.8314(3) A, c = 21.1658(8) A, beta = 116.6400(10) degrees, Z = 8 (T = 295 K).     

Automated parallel investigations/optimizations of the reversible addition‐fragmentation chain transfer polymerization of methyl methacrylate

Poly(methyl methacrylate)s were successfully synthesized in a controlled fashion via reversible addition‐fragmentation chain transfer polymerizations utilizing an automated synthesizer. Sixteen polymers were synthesized in a parallel way utilizing the Chemspeed Accelerator? SLT100 to investigate the reproducibility and the control over the polymerizations. The obtained polymers were characterized by gel permeation chromatography (GPC) and automated MALDI TOFMS measurements, thereby proving the reproducibility and controllability of the investigated automated setup. Furthermore, temperature optimization reactions were performed utilizing an individually heatable reactor block. Moreover, to demonstrate the presence of active polymer chains in the reaction mixture, chain extension polymerizations were performed on the automated synthesizer. The results obtained from these chain extension experiments demonstrate the possibility to design well‐defined A‐b‐B block copolymers with different monomers as building units. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5775–5783, 2004     

Solvent extraction of alkaline earth metal picrates with poly- and bis(crown ether)s

Summary Solvent extraction of alkaline earth metal picrates with poly- and bis(crown ether)s containing benzo-15-crown-5- and benzo-18-crown-6 moieties was carried out in a water-chloroform system. The poly- and bis(crown ether)s showed larger extractability for the metal picrates than the corresponding monocyclic crown ethers. Especially, poly- and bis(benzo-15-crown-5), and bis(benzo-18-crown-6) were found to have relatively high extractability and selectivity for Ba²⁺ and Sr²⁺, respectively.

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Lösungsmittelextraktion von Erdalkalipikraten mit Hilfe von Poly- und Bis-Kronenethern

Zusammenfassung Poly- und Bis-Kronenether mit Benzo-15-krone-5- und Benzo-18-krone-6-Einheiten wurden zur Extraktion von Erdalkalipikraten im Wasser-Chloroform-System verwendet. Die genannten Ether zeigten eine bessere Extraktionsfähigkeit für die Pikrate als die entsprechenden monocyclischen Kronenether. Im Falle von Ba²⁺ und Sr²⁺ ergab sich eine besonders gute Extrahierbarkeit und Selektivität mit Poly- und Bis(benzo-15-krone-5)- und Bis(benzo-18-krone-6)-Ethern.

     

水溶性Fe3O4磁性纳米催化剂的合成及应用

利用对氨基苯磺酸氟硼酸重氮盐与Fe₃O₄磁性纳米粒子(MNPs)的偶联反应,非常方便地制备出表面含有磺酸基的Fe₃O₄磁性纳米粒子。 透射电子显微镜(TEM) 测试结果表明,粒子的平均粒径在 20 nm左右。 溶解性实验表明,该纳米粒子具有较好的水溶性,但不溶于常用的有机溶剂,因此可利用其磁性回收并循环使用。 将该纳米粒子用于催化羧酸与醇的酯化反应,产物酯的收率为71%~86%。 催化剂在酯化反应中的最优使用量为1.5%(质量分数)。 同时,该催化剂可催化果糖合成5-羟甲基糠醛(HMF),收率为32%。     

Cation-binding properties of poly- and bis(benzo-21-crown-7)derivatives

Summary Poly- and bis(crown ether)s which contain the relatively large crown ether ring of benzo-21-crown-7 were synthesized, and their cation-binding properties for alkali metal cations were elucidated by solvent extraction and also conductometrically. The cation-binding ability was found to decrease in the order Cs⁺>Rb⁺>K⁺>Na⁺. They can extract alkali metal cations more efficiently than the corresponding monomeric analogue. The binding behaviour for some organic cations such as alkyl ammonium and guanidinium is also described.

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Kationen-Bindungsvermögen von Poly- und Bis(benzo-21-krone-7)-Derivaten

Zusammenfassung Poly- und Bis-kronenether mit dem relativ großen Kronenetherring Benzo-21-krone-7 wurden dargestellt und ihr Bindungsvermögen für Alkaliionen wurde durch Lösungsextraktion und auch konduktometrisch untersucht. Es ergab sich, daß das Bindungsvermögen in der Reihenfolge Cs⁺>Rb⁺>K⁺>Na⁺ abnimmt. Diese Substanzen können Alkaliionen wirksamer extrahieren als die entsprechenden Monomeren Analogen. Das Bindungsvermögen für einige organische Kationen, wie z.B. Alkylammonium und Guanidinium, wurde ebenfalls untersucht.

     

Direct synthesis of the arylboronic acid analogues of phenylglycine via microwave-assisted four-component Ugi reaction

A four-component Ugi reaction (Ugi-4CR) utilizing formylphenyl boronic acids under mild condition was developed for the synthesis of arylboronic acid analogs. The reactions were performed in methanol and accelerated by microwave irradiation, which makes this strategy suitable for constructing boronic-containing chemical libraries. Two of the synthesized analogs were found to have cytotoxic activity against HepG2, MDA-MB231, and A549 cancer cell lines, demonstrating the potential application of this approach in developing novel boron-containing pharmaceuticals.     

Synthesis and cation-binding properties of poly-and bis(thiacrown ether)s

Poly- and bis(thiacrown ether) derivatives in which some oxygen atoms of benzocrown ether moiety are replaced by sulfur atoms have been synthesized. Their cation-binding abilities were investigated by using the solvent extraction method. The poly- and bis(benzothiacrown ether)s showed great affinity for silver ion, being more excellent in the affinity than the corresponding monocyclic analogs. They, however, possess very poor cation-binding ability for alkali and alkaline-earth metal ions. The poly- and bis(thiacrown ether)s also bind mercuric ions effectively, whereas the corresponding monomeric analogs do not at all.     

Synthetic study of carbapenem antibiotics I. (±)-2-cyclopropyl-6-(1′-hydroxyethyl)-1-carbapen-2-em-3-carboxylic acid

A synthetic scheme extensively utilizing silylation-desilylation reactions to achieve the total synthesis of 2,6-substituted carbapenem antibiotics from readily available azetidinones is reported. An epimeric pair of new 2,6-substituted carbapenems, (±)-2-cyclopropyl-6-(1′-hydroxyethyl)-1-carbapen-2-em-3-carboxylic acids were synthesized.     

Synthesis of sultam scaffolds via intramolecular oxa-Michael and diastereoselective Baylis-Hillman reactions

A divergent synthetic approach to new sultams utilizing intramolecular oxa-Michael and Baylis-Hillman reactions of readily prepared vinyl sulfonamides and suitably protected amino alcohols, is reported. A variety of seven- and eight-membered ring sultam scaffolds were synthesized using oxa-Michael pathways, whereas both five- and six-membered rings were synthesized using Baylis-Hillman methods. Baylis-Hillman reactions proceed with good to excellent levels of diastereoselectivity, and oxa-Michael reactions leading to eight-membered ring sultams provide empirical evidence validating 8- endo-trig cyclization pathways.