1,3,5-三[(4’-乙炔基苯基)乙炔基]苯的合成

设计了多种合成路线制备芳香炔基树枝状化合物中间体1,3,5-三[(4’-乙炔基苯基)乙炔基]苯,通过一系列的合成路线和反应条件的对比,发现多官能团的端基炔化合物与芳基溴化合物之间发生多重Sonogashira反应时,常会生成不同取代程度的极性相似化合物,因而难以分离.采用多官能团的端基炔化合物与芳基碘化合物反应可以避免这种情况.最终确定以1,3,5-三溴苯和2-甲基-3-丁炔-2-醇为原料,制得中间产物1,3,5-三乙炔基苯;再以对碘苯胺和三甲基硅乙炔为原料,经重氮化化、卤代反应制得4-三甲基硅乙炔基碘苯;后者与1,3,5-三乙炔苯经Sonogashira反应、裂解去保护反应,制得化合物1,3,5-三[(4’-乙炔基苯基)乙炔基]苯.用1H NMR,13C NMR,元素分析等表征手段确认了中间体及最终产物的结构.     

带有不同端炔保护基团的新型苯乙炔树枝状化合物的合成

以1,3,5-三溴苯为原料,通过Sonogashira反应,设计并合成了两种带有不同端炔保护基团的1,3,5-取代的苯乙炔树枝状化合物:1,3,5-三[3-(3-甲基-3-羟基-1-丁炔基)-5-(三异丙基硅乙炔基)苯基乙炔基]苯(B1)和1,3,5-三[3-(三甲基硅乙炔基)-5-(三异丙基硅乙炔基)苯基乙炔基]苯(B2),并对合成路线的选择进行了比较和讨论.用1H NMR,13C NMR,质谱,元素分析等表征手段确认了中间体及最终产物的结构.这两种苯乙炔树枝状化合物各自带有两类不同的周边端炔保护基团,可根据其脱保护条件的不同引入不同的周边功能基团.     

用基于苯并噻二唑衍生物的比率荧光化学传感器检测氟离子

研制了一种用于灵敏、快速地检测溶液中的氟离子的基于苯并噻二唑衍生物的荧光传感器.4,7-二溴-2,1,3-苯并噻二唑与三甲基硅基乙炔通过Sonogashira偶联反应得到二取代的三甲基硅基乙炔苯并噻二唑;将该化合物用于检测氟离子,分析了检测灵敏度和选择性.结果表明,在乙腈和水(V/V=9∶1)混合溶液中,合成的苯并噻二唑衍生物的最大发射波长峰值为455nm(激发波长为376nm);就所测试的F-,Cl-,Br-,I-,ClO4-,AcO-,NO3-,H2PO3-,CN-和HSO4-等阴离子而言,仅F-可以脱除三甲基硅保护基使得该化合物荧光最大发射波长蓝移至435nm,荧光强度降低60%,且最低检测限可达4.5×10-8 mol/L.因此,二取代的三甲基硅基乙炔苯并噻二唑应用于氟离子检测具有很好的灵敏度和选择性.     

3-炔基咪唑并[1,2-b]哒嗪的简便合成

以咪唑并[1,2-b]哒嗪为原料,与N-碘代丁二酰亚胺在三氟乙酸/二氯甲烷中于室温进行碘代反应制得3-碘咪唑并[1,2-b]哒嗪(3);3与三甲基硅基乙炔在Pd(OAc)_2催化下经Sonogashira偶联反应制得3-三甲基硅基乙炔基咪唑并[1,2-b]哒嗪(4);4在碳酸钾作用下脱除三甲基硅基合成了3-炔基咪唑并[1,2-b]哒嗪,总收率61.2%,其结构经~1H NMR和HR-MS确证。     

五苯基苯基硅化合物及其原料苯乙炔基硅化合物的合成

近年来,我们从事多苯基芳基类有机硅化合物的合成。并发现这类化合物对有机硅高聚物的热稳定性有一定的影响^[1.2]。本文研究了五苯基苯基硅化合物的合成。其主要方法是以苯乙炔基有机硅化合物与四苯基环戊二烯酮为原料,通过Diels-Alder反应来合成的。有的文献认为苯乙炔基硅烷由于电子效应与位阻关系,除苯乙炔基三甲基硅烷外,一般不容易与四苯基环戊二烯酮进行缩合^[3]。根据我们的实验却得到了较好产率的各种五苯基苯基有机硅化合物,而且产物也易于分离。同时我们还对原料苯乙炔基甲基二乙氧基硅烷的合成进行了研究。     

N-（ω-三丁基锡聚乙氧基醚）邻苯二甲酰亚胺的光诱导单电子转移成环反应

研究了N-（ω-三丁基锡聚乙氧基醚）邻苯二甲酰亚胺在甲醇溶剂中的光反应,并与文献报道的N-（ω-三甲基硅聚乙氧基醚）邻苯二甲酰亚胺在甲醇中的光反应结果进行了比较.发现光诱导单电子转移-脱三丁基锡成环反应过程比光诱导单电子转移-脱三甲基硅成环反应过程效率更高,表明提高离去基团的离去能力可以提高单电子转移成环反应的选择性和...     

聚(4-三甲基硅基)苯乙炔膜的气体透过性

合成了4-三甲基硅基苯乙炔(SPA)单体,采用核磁共振谱(1H-NMR)和傅里叶变换红外光谱(FT-IR)对其进行了表征.在Pd(PPh3)2Cl2和金属共催化剂催化下制备了聚4-三甲基硅基苯乙炔(PSPA).PSPA易溶于氯仿、甲苯等有机溶剂,成膜性较好,具有较高的强度和热稳定性.热重分析(TGA)表明其5%失重温度为300～310℃.PSPA膜对CO2气体透过系数达到848 Barrer,并具有较高的透过选择性,分离系数达到12.68,摆脱了"Robeson"上限的限制.     

2-乙酰基-6-三甲基硅基苯基三氟甲磺酸酯的合成

以2-三甲基硅基苯酚为原料,经甲酰化、酯化、亲核加成和氧化反应首次合成了3-乙酰基苯炔的前体——2-乙酰基-6-三甲基硅基苯基三氟甲磺酸酯,总收率35%,其结构经1H NMR和13C NMR确证。     

3-[P-(P-(P-甲氧基苯乙炔基)苯乙炔基)苯氧基]丙烯酸丙酯合成与表征

以对甲氧基苯乙炔、对溴苯酚、3-氯-1-丙醇和甲基丁炔醇等为原料,通过williamson反应、Sonogashina和酯化等反应合成3[P-(P-(P-甲氧基苯乙炔基)苯乙炔基)苯氧基]丙烯酸丙酯.用元素分析,IR和1HNMR等手段对产物的组成和结构进行了表征,并讨论反应物量、催化剂等因素对产率的影响.     

8-三甲基硅乙炔基-6-吡啶-2-基-4H-苯并[f]咪唑并[1,5-a][1,4]二氮杂-3-羧酸乙酯的合成

报道了GABA_A受体的α2/α3选择性配体(HZ-166)的关键中间体8-三甲基硅乙炔基-6-吡啶-2-基-4H-苯并[f]咪唑并[1,5-a][1,4]二氮杂-3-羧酸乙酯(HZ-165)的一种合成方法。该方法以4-溴-2-(2’-吡啶基羰基)苯胺为原料,经亲核加成、关环反应、Vilsmeier-Haack反应和Sonogashira反应合成得到目标产物,产物结构经¹H NMR和MS(ESI)确证。      

Synthesis and property of helical poly(phenylacetylene)s bearing chiral ruthenium complexes and real space imaging of meso- and nanoscopic structures by atomic force microscopy

Novel sets of helical poly(phenylacetylene)s bearing a chiral ruthenium (Ru) complex with opposite chirality (Δ and Λ forms) as a bulky pendant (poly- 1 and poly- 2 ) were synthesized through the polymerization of the corresponding optically pure phenylacetylenes with a rhodium catalyst, and their structures in solution and morphology on solid substrates were investigated with NMR, ultraviolet–visible, and circular dichroism (CD) spectroscopies and with atomic force microscopy (AFM), respectively. The obtained cis–transoidal polymers (poly- 1 and poly- 2 ) showed characteristic Cotton effects in the region of metal-to-ligand charge transfer of the chiral Ru pendants. Poly- 1 and poly- 2 were thought to have a predominantly one-handed helical conformation induced by the chiral pendants. However, the apparent Cotton effects derived from the helically twisted π-conjugated polymer backbone could not be observed, probably because of the strong chiral chromophoric pendants. However, in the AFM images, the helical polymers adsorbed on mica could be easily discerned as isolated strands, and the visualization and discrimination of the right- and left-handed helical structures of the chiral polymers were achieved by high-resolution AFM imaging. On the basis of the AFM observations together with the CD measurements and computational calculation results, possible structures of poly- 1 and poly- 2 were examined. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4621–4640, 2004     

Switching of macromolecular helicity of optically active poly(phenylacetylene)s bearing cyclodextrin pendants induced by various external stimuli

A series of novel phenylacetylenes bearing optically active cyclodextrin (CyD) residues such as alpha-, beta-, and gamma-CyD and permethylated beta-CyD residues as the pendant groups was synthesized and polymerized with a rhodium catalyst to give highly cis-transoidal poly(phenylacetylene)s, poly-1alpha, poly-2beta, poly-3gamma, and poly-2beta-Me, respectively. The polymers exhibited an induced circular dichroism (CD) in the UV-visible region of the polymer backbones, resulting from the prevailing one-handed helical conformations. The Cotton effect signs were inverted in response to external chiral and achiral stimuli, such as temperature, solvent, and interactions with chiral or achiral guest molecules. The inversion of the Cotton effect signs was accompanied by a color change due to a conformational change, such as inversion of the helicity of the polymer backbones with a different twist angle of the conjugated double bonds, that was readily visible with the naked eye and could be quantified by absorption and CD spectroscopies. The dynamic helical conformations of poly-2beta showing opposite Cotton effect signs in different solvents could be further fixed by intramolecular cross-linking between the hydroxy groups of the neighboring beta-CyD units in each solvent. The cross-link between the pendant CyD units suppressed the inversion of the helicity; therefore, the cross-linked poly-2betas showed no Cotton effect inversion, although the polymer backbones were still flexible enough to alter their helical pitch with the same handedness, resulting in a color change depending on the degree of intramolecular cross-linking.     

Poly(phenylacetylene)s bearing a peptide pendant: helical conformational changes of the polymer backbone stimulated by the pendant conformational change

Optically active, cis-transoid poly(phenylacetylene) derivatives bearing a poly(gamma-benzyl-L-glutamate) [poly(PBGAm)] or poly(L-glutamic acid) [poly(PGAm)] chain as the pendant were prepared by polymerisation of the corresponding macromonomer with a rhodium catalyst followed by hydrolysis of the pendant ester groups. Their conformational changes in solution, induced by a helix-coil transition of the pendant polypeptides, were investigated using circular dichroism (CD) and absorption spectroscopies. A series of macromonomers with a different peptide chain lengths was synthesised by the polymerisation of the N-carboxyanhydride of gamma-benzyl-L-glutamate with a phenylacetylene bearing an alanine residue as the initiator. The obtained macromonomers (PBGAm) were further polymerised with a rhodium catalyst in N,N-dimethylformamide (DMF) to yield novel poly(phenylacetylene)s [poly(PBGAm)] with a poly(gamma-benzyl-L-glutamate) pendant. The poly(PBGAm) exhibited an induced circular dichroism (ICD) in the UV/Vis region of the polymer backbone in dimethyl sulfoxide (DMSO), probably due to the prevailing one-handed helix formation. The Cotton effect signs of a DMSO solution of the poly(PBGAm) were inverted and accompanied by a visible colour change in the presence of an increasing amount of chloroform or DMF containing lithium chloride. The results suggest that poly(PBGAm) may undergo a conformational change such as a helix-helix transition with a different helical pitch responding to a change in the alpha-helix content of the poly(gamma-benzyl-L-glutamate) pendant. Moreover, a water-soluble poly(PGAm) also showed a similar, but dramatic change in its helical conformation with a visible colour change stimulated by a helix-coil transition of the pendant poly(L-glutamic acid) chains by changing the pH in water.     

Helical arrays of pendant fullerenes on optically active poly(phenylacetylene)s

Novel, optically active, stereoregular poly(phenylacetylene)s bearing the bulky fullerene as the pendant were synthesized by copolymerization of an achiral phenylacetylene bearing a [60]fullerene unit with optically active phenylacetylene components in the presence of a rhodium catalyst. The C60-bound phenylacetylene was prepared by treatment of C60 with N-(4-ethynylbenzyl)glycine in a Prato reaction. The obtained copolymers exhibited induced circular dichroism (ICD) in solution both in the main-chain region and in the achiral fullerene chromophoric region, although their ICD intensities were highly dependent on the structures of the optically active phenylacetylenes and the solution temperature. These results indicate that the optically active copolymers form one-handed helical structures and that the pendant achiral fullerene groups are arranged in helical arrays with a predominant screw sense along the polymer backbone. The structures and morphology of the copolymers on solid substrates were also investigated by atomic force microscopy.     

Synthesis and polymerization of oligo(oxyethylene) macromonomer bearing sodium sulfonate

Oligo(oxyethylene) macromonomers bearing sodium sulfonate group have been synthesized through four reactions: (1) ring-opening polymerization of oxirane, (2) etherification of monomethoxyl oligo(oxyethylene) and epichlorohydrin, (3) sulfonation of cycloxyl compound, and (4) end-capping of sodium oligo(oxyethylene) sulfonate by methacrylic group. A desired length of oligo(oxyethylene) in the macromonomers can easily be achieved by controlling the ratio of reactants in the ring-opening step. The structures of the products of each reaction were identified by IR, ¹H-NMR, and GPC. Polymers of the monomers were also characterized by GPC and DSC. © 1993 John Wiley & Sons, Inc.     

Synthesis of Hydroxy-Functional PMMA Macromonomers by Anionic Polymerization

Living anionic polymerization has been utilized to synthesize hydroxy end-functionalized PMMA macromonomers with styryl or allyl functionalities as the polymerizable end-groups. Protected hydroxy-functionalized alkyl lithium initiators have been used to initiate anionic polymerization of MMA. Subsequently the living chains with protected hydroxyl function have been terminated using 4-vinylbenzyl chloride (4-VBC) or allyl methacrylate (ALMA) to form α-hydroxy-ω-styryl and α-hydroxy-ω-allyl PMMA, respectively. These protected hydroxy-functionalized PMMA macromonomers have been characterized by GPC and ¹H-NMR. Termination using 4-VBC led to 50% functionalization, whereas that using allyl methacrylate led to 100% functionalization of the hydroxy-PMMA.     

Detection and amplification of a small enantiomeric imbalance in alpha-amino acids by a helical poly(phenylacetylene) with crown ether pendants

We have designed a novel stereoregular poly(phenylacetylene) bearing the bulky crown ether as the pendant (poly-1) for the amino acid binding site. The polymer forms a one-handed helix upon complexation with l-amino acid perchlorates, and the complexes exhibit an induced circular dichroism (ICD) with the same Cotton effect signs in the polymer backbone region through a significant cooperative interaction. Poly-1 is highly sensitive to the amino acid chirality and can detect an extremely small enantiomeric imbalance in alpha-amino acids (less than 0.005% enantiomeric excess of alanine, for example).     

Main-chain optically active riboflavin polymer for asymmetric catalysis and its vapochromic behavior

A novel optically active polymer consisting of riboflavin units as the main chain (poly-1) was prepared from naturally occurring riboflavin (vitamin B(2)) in three steps. The riboflavin residues of poly-1 were converted to 5-ethylriboflavinium cations (giving poly-2), which could be reversibly transformed into the corresponding 4a-hydroxyriboflavins (giving poly-2OH) through hydroxylation/dehydroxylation reactions. This reversible structural change was accompanied by a visible color change along with significant changes in the absorption and circular dichroism (CD) spectra. The nuclear Overhauser effect spectroscopy (NOESY) and CD spectra of poly-2 revealed a supramolecularly twisted helical structure with excess one-handedness through face-to-face stacking of the intermolecular riboflavinium units, as evidenced by the apparent NOE correlations between the interstrand riboflavin units and intense Cotton effects induced in the flavinium chromophore regions. The hydroxylation of poly-2 at the 4a-position proceeded in a diastereoselective fashion via chirality transfer from the induced supramolecular helical chirality assisted by the ribityl pendants, resulting in a 83:17 diastereomeric mixture of poly-2OH. The diastereoselectivity of poly-2 was remarkably higher than that of the corresponding monomeric model (64.5:35.5), indicating amplification of the chirality resulting from the supramolecular chirality induced in the stacked poly-2 backbones. The optically active poly-2 efficiently catalyzed the asymmetric organocatalytic oxidation of sulfides with hydrogen peroxide, yielding optically active sulfoxides with up to 60% enantiomeric excess (ee), whose enantioselectivity was higher than that catalyzed by the monomeric counterpart (30% ee). In addition, upon exposure to primary and secondary amines, poly-2 exhibited unique high-speed vapochromic behavior arising from the formation of 4a-amine adducts in the film.     

Metal-induced supramolecualr chirality in an optically active polythiophene aggregate

Chiral polythiophenes (PTs), in sharp contrast to other optically active polymers, exhibit optical activity in the pi-pi* transition region which is derived from the chirality of the main chain when they self-assemble to form a supramolecular pi-stacked aggregate with intermolecular interactions in a poor solvent or in a film. We now report that the regioregular, optically active PT poly[(R)-3-[4-(4-ethyl-2-oxazolin-2-yl)phenyl]thiophene] (poly-1) exhibits unique split-type induced circular dichroism (ICD) in the pi-pi* transition region of the main chain upon complexation with various metal salts such as trifluoromethanesulfonates of copper(I), copper(II), silver(I), and zinc(II), and iron(II) perchlorate in chloroform, which is a good solvent for poly-1. The appearance of ICD and slight changes in the UV/Vis spectra (no color change), except for the zinc salts, indicated that the chirality may not be induced by chiral pi-stacked aggregates of poly-1, but by the chirality of the main chain, for example, a predominantly one-handed helical structure induced by intermolecular coordination of the oxazoline groups to metal ions. The sign of the Cotton effect depends on the metal salt; most metal salts induced ICDs with similar Cotton-effect patterns, while zinc salts caused an inversion of the signs of the Cotton effect of poly-1 accompanied by a gradual red shift in the absorption of up to 125 nm. The changes in the conformation and the size of the poly-1 aggregates induced by different metal salts were also investigated by (1)H NMR titrations, static light scattering (SLS), atomic force microscopy (AFM), and membrane filtration. On the basis of these results, we propose a possible model for the chiral supramolecular aggregates of poly-1 with metal salts.     

Synthesis of helical poly(phenylacetylene)s bearing cinchona alkaloid pendants and their application to asymmetric organocatalysis

Four novel dynamic helical poly(phenylacetylene)s bearing cinchona alkaloids as pendant groups were synthesized starting from the commercially available cinchona alkaloids, cinchonidine, cinchonine, quinine, and quinidine, by the polymerization of the corresponding phenylacetylene monomers with a rhodium catalyst. These polymers exhibited an induced circular dichroism (ICD) in the UV–visible region of the polymer backbones in solution, resulting from the preferred‐handed helical conformation induced by the optically active cinchona alkaloid pendants. In response to the solvent used, their Cotton effect patterns and intensities were significantly changed accompanied by the changes in their absorption spectra probably due to the changes in their helical conformations, such as the inversion of the helical sense or helical pitch of the polymers. When these helical polymers were used as polymeric organocatalysts for the asymmetric conjugated addition and Henry reactions, the optically active products with a modest enantiomeric excess were obtained whose enantioselectivities were comparable to those obtained with the corresponding cinchona alkaloid‐bound monomers as the catalysts. However, we observed a unique enhancement of the enantioselectivity and a reversal of the stereoselectivity for some helical polymers, suggesting the important role of the helical chirality during the asymmetric organocatalysis. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011