含长链亚烷基桥的芳炔类共轭大环的合成

采用模板导向法高产率地合成了两个含长链亚烷基桥的芳炔类共轭大环. 通过四碘化合物与单保护双炔化合物的四重Hagiraha偶合反应构建了环化所需要的复杂前体. 通过相应的模板四炔衍生物的分子内Glaser 偶合反应环化得到大环. 大环的结构用NMR, GPC 及UV-Vis表征确证.     

芳炔大环的结构与超分子性质

芳炔大环是由芳(杂)环和炔键构成的具有规整多边形环状分子结构的化合物,自问世以来即受到化学家和材料学家的广泛关注。芳炔大环具有不会坍塌的刚性骨架,环上特定位置可带有柔性侧链或取代官能团,环平面上大的π电子共轭体系和环上灵活的结合点赋予芳炔大环独特而有趣的超分子性质。本文对芳炔大环的超分子性质作了综述,从大环在溶液中的缔合、热致液晶性质、一维超分子自组装及在基底表面或固-液界面二维自组装4个方面展开评述,介绍了研究方法,着重讨论了分子结构与物质性质的关系,并对芳炔大环的应用前景做了展望,为通过合理设计分子结构来制备满足尺寸、形状及功能要求的新型材料提供借鉴。     

1,1-二溴-2-取代苯基乙烯在环化反应中的应用

1,1-二溴-2-取代苯基乙烯是一种重要的有机合成中间体,该类化合物可以以芳醛为原料,通过Corey-Fuch法简便制备,并广泛应用于多取代烯烃、(E)-1-溴-2-取代苯基乙烯、芳炔、1,3-二炔(多炔)、芳炔溴化物和炔胺等化合物的合成。1,1-二溴-2-取代苯基乙烯中的(E)-Br和(Z)-Br存在明显的反应活性差异,因而适合于设计各种串联反应路线。近年来,利用其(E)-Br参与的Stille反应,Heck反应,Suzuki-Miyaura反应,Buchwald-Hartwig等各种偶联反应以及(Z)-Br和取代苯基邻位各种活性反应基团之间的环化反应,以1,1-二溴-2-取代苯基乙烯衍生物为底物合成了异香豆素类、茚类、吲哚类、异吲哚类、苯并噻吩和苯并呋喃类等多种具有重要生理活性或有合成价值的稠(杂)环化合物。本文从合成的化合物类别角度出发,对该领域近年来的研究进展进行了回顾和展望。     

液晶性直线型共轭芳炔衍生物的合成及电致发光性质

以苯胺和芳炔为基本构筑单元,通过Sonogashira偶联反应, 合成了一种新型含氨基的结构不对称π共轭线性芳炔化合物5-{(6-己氧基萘基)丁二炔}-2-{(4-氨基苯基)乙炔}苄醇。 通过化学修饰在芳炔类小分子端基引入氨基取代基,使其在无吸电子基团存在的条件下通过扭转态的形成实现分子内电荷的有效转移,从而提高芳炔类衍生物电-光转换效率。 同时,通过赋予芳炔类小分子液晶性,有效改善电子与空穴在器件中的电荷平衡,提高器件的效率。 基于氨基取代芳炔衍生物为掺杂发光材料制备的电致发光器件呈现黄绿光发射,器件开启电压较低(7.20 V),显示了较好的电致发光稳定性,器件17.65 V时达到最大亮度126 cd/m²,是一种潜在的电致发光材料。     

四炔的芳炔环加成反应简便合成芳胺

芳胺作为一种合成砌块广泛存在于天然产物、医药品及分子材料中.诸如一些亲核芳香取代、亲电硝化还原、及过渡金属促进的氨基化合物芳基化作用等作为合成策略在Caryl—N键形成领域被长期应用.本工作在无金属催化条件下通过四炔的芳炔环加成(Hexadehydro-Diels-Alder,HDDA)反应高效合成了芳胺化合物.该反应特征表现在无金属催化、无添加剂、无氧化剂、无导向基团前体,反应在温和条件下高产率地得到炔官能化二环化合物并表现了优越的区域选择性.所合成产物的结构经各种波谱手段表征确证,其中化合物3h的结构还通过X射线单晶衍射分析确认.     

联炔环化反应研究进展

联炔是一种具有较高反应活性的有机合成中间体,与单炔相比联炔具有共轭结构和更多的反应活性位点,既能够作为四合成子构建单环化合物,也能够发生串联环化反应形成多环化合物,因此成为有机化学家的研究热点。本文综述了近年来联炔环化反应的研究进展,并对该领域未来的发展方向进行了展望。     

结构多样的HIV-1整合酶抑制剂:过去、现在和未来

HIV-1整合酶是逆转录病毒复制的必需酶,它催化病毒DNA与宿主染色体DNA的整合,而且在人类细胞中没有类似物,因此成为治疗艾滋病的富有吸引力和合理的靶标.最近十年,一大批HIV-1整合酶抑制剂被鉴定出来,其中一些化合物显示选择性的抑制HIV-1整合酶和阻断病毒复制的活性,而最有影响的两类抑制剂是含邻苯二酚的多羟基芳环化合物和最近报道的芳基β-二酮酸类化合物.全面综述了用于HIV-1整合酶抑制剂研究以发展抗HIV新药的不同种类的化合物,包括苯并咪唑类衍生物、核苷类、多肽、羟基取代的芳环化合物及二酮酸类化合物等,并阐述了这些化合物中对抑制活性重要的结构特征.同时也介绍了HIV-1整合酶的结构、功能以及HIV-1整合酶抑制剂的设计原理和作用机制.     

均相催化中的结构研究(摘要)

在许多金属催化的有机反应中,能形成金属杂环化合物,举二类反应为例。 1.炔-烯的共齐聚反应炔类的环三聚反应,早已发现。一般用镍催化剂:但是,要使二份炔和一份烯及应而成环己二烯衍生物:则不易达到,因有一竞争反应,所得主要为三份炔的环聚物。有人假设这一反应的中间体是金属杂环化合物(Ⅰ):     

新型丁二炔-二酰胺大环化合物的合成及与TTF和DNP在溶液中的络合行为

由三甘醇和四甘醇出发,经炔丙基烷基化、Mitsunobu反应和Eglinton偶联反应3步合成了2个含均苯四甲酸二酰亚胺结构单元以及丁二炔结构单元的大环化合物,关环产率分别为81%和85%.大环化合物及中间体的化学结构经核磁共振氢谱、碳谱、低分辨质谱、高分辨质谱或元素分析等确认.通过氘代丙酮中1HNMR实验以及氯仿中紫外滴定实验研究了这类大环化合物与客体分子四硫富瓦烯(TTF)和1,5-二甲氧基萘(DNP)在溶液中的相互作用,结果发现,大环化合物的核磁化学位移及紫外光谱均发生变化.通过得到的主-客体间的络合常数可知,此类新型大环化合物与TTF和DNP之间有一定的络合作用.     

钯催化炔碘与有机锡化合物交叉偶联反应

以钯为催化剂,DMEDA为配体,实现了碱性条件下炔碘化合物与有机锡化合物的Stille交叉偶联反应,合成了一系列芳环上含有甲基、甲氧基及卤原子的中间炔烃。该方法底物适应范围广、产率高,为C—C键的构筑提供了一条新路径。     

带内取向柔性多醚链苯炔大环合成

采用分子间Glaser半环闭环法合成了带内取向柔性多醚链的苯炔大环.用1H NMR,13C NMR,HRMS,UV及PL(photduminescence)确证了目标大环结构,凝胶色谱测定了目标大环纯度.经偏光显微镜(POM)和差热分析仪(DSC)测试表明大环没有呈现预期的液晶性质,可能是由于环内柔性链过于拥挤,不能形成与环平面共面结构,以至于难于进行有序堆积的缘故.     

芳酰胺类大环一步高效合成及其成环机理研究进展

总结了最近发现的新型芳酰胺及芳酰肼大环一步合成反应,着重探讨了由分子内三中心氢键所引导的高效一步成环反应机理.这类反应是由未成环寡聚物前体的折叠构象所构筑,不仅高效,而且反应机理新颖,提供了传统成环反应难以得到的几类刚性大环的合成方法.这些大环化合物表现出对客体识别的高度专一性,并能形成具有高通量性的跨膜孔道.     

Rigidity versus amphiphilicity in transmembrane nanopore formation by cholate-based macrocycles

Amphiphilic macrocycles consisting of cholates and l-tryptophan were prepared by the copper-catalysed alkyne–azide cycloaddition. The macrocycles helped glucose permeate lipid bilayer membranes. The macrocycle with two cholates was significantly more active in the glucose transport than the one with three cholates. Inclusion of 30–50% cholesterol in the bilayer accelerated the glucose transport monotonously. The unusual cholesterol effect was explained by the hydrophobically driven pore formation, in which the associative interactions of the water molecules inside the macrocycles prompted the macrocycles to stack over one another to avoid unfavourable water–lipid hydrocarbon contact. Fluorescence quenching by water- and oil-soluble quenchers provided additional evidence for the better penetration of the dicholate macrocycle into the bilayers, consistent with the stacking model. Rigidity in the macrocycle structure was hypothesised to be the main reason for the higher transport activity and deeper membrane-penetration of the dicholate macrocycle compared with those of the tricholate.     

A Supramolecular Strategy for the Synthesis of Cyclic Oligomers and Polymers by Ring Expansion

Ring-opening metathesis polymerization (ROMP) of strained macrocycles is a key method to prepare diverse polymers. However, lack of ring strain in most macrocycles is an impediment to polymerization. In this paper, the polymerization/oligomerization of unstrained macrocycles was achieved using a supramolecular approach, leading selectively to cyclic products. Diphenyl thiourea and other guest molecules were used as additives to the ROMP reaction of unstrained macrocycles. An intermediate host-guest complex leads to the stabilization of the open form of the macrocycle after treatment with Grubbs catalysts, thereby favoring polymerization by inhibiting the ring-closing reaction back to the monomer. This proof-of-concept enables ring-expansion polymerization of unstrained macrocycles leading to cyclic polymers with molecular weights up to 6700 Da.     

Synthesis and properties of template-promoted switchable dithienylethenebased macrocycles

Three switchable macrocycles based on photochromic dithienylethene were synthesized under the template of dibenzylammonium hexafluorophosphate. Their structure were well-confirmed by NMR, ESI-MS and X-ray diffraction. Their photochromism indicated that they showed good reversibility in solution. Additionally, the theoretical calculation suggested that photoirradiation can change the cavity of macrocycles.     

Cyclooctapyrroles, novel macrocycles containing biladiene-a,c units

Cyclooctapyrroles, novel macrocycles containing two biladiene-a,c units, were synthesized in high yield from the condensation of 3,3′-dipyrromethanes with 5,5′-diformyl-2,2′-dipyrromethane under acidic conditions. These macrocycles form dinuclear complexes with zinc(II).     

Excimer‐Based On‐Off Bis(pyreneamide) Macrocyclic Chemosensors

A series of bis(pyreneamide) macrocycles, synthesized in two steps from THF, THP, oxepane and 1,4‐dioxane, are tested as chemosensors for a large range of mono‐, di‐ and trivalent cations. In their native states, these macrocycles exhibit a strong excimer fluorescence that is quenched upon the addition of the metal ions (alkaline, alkaline earth, p‐, d‐, and f‐block metals). UV‐Vis spectrophotometric titrations, cyclic voltammetry, excimer fluorescence quenching, and transient absorption spectroscopy experiments helped characterize the On‐Off changes occurring upon binding and demonstrate that the highest stability constants are obtained with divalent cations Ca²⁺ and Ba²⁺ specifically.     

Accessing Improbable Foldamer Shapes with Strained Macrocycles

The alkylation of some secondary amide functions with a dimethoxybenzyl (DMB) group in oligomers of 8-amino-2-quinolinecarboxylic acid destabilizes the otherwise favored helical conformations, and allows for cyclization to take place. A cyclic hexamer and a cyclic heptamer were produced in this manner. After DMB removal, X-ray crystallography and NMR show that the macrocycles adopt strained conformations that would be improbable in noncyclic species. The high helix folding propensity of the main chain is partly expressed in these conformations, but it remains frustrated by macrocyclization. Despite being homomeric, the macrocycles possess inequivalent monomer units. Experimental and computational studies highlight specific fluxional pathways within these structures. Extensive simulated annealing molecular dynamics allow for the prediction of the conformations for larger macrocycles with up to sixteen monomers.     

环芳酰胺的合成及自组装行为

本文主要综述了近年来由三中心氢键和远程位阻效应促进的环芳酰胺合成,以及利用该类化合物进行自组装行为的研究进展. 在研究一步高效成环的基础上,对合成不同孔径刚性大环的方法进行了探讨. 改变大环周边侧链的性质可以调控这类大环分子的自组装行为. 最后对环芳酰胺的应用进行了简单介绍     

Synthesis,isolation, characterization,and properties of small-size aromatic macrocycles for poly(arylene ether ketone)s

A series of macrocyclic arylene ether ketone oligomers from 4,4′-difluorobenzophenone, 2,4′-difluorobenzophenone and 1,3-bis(4′-fluorobenzoyl)benzene were prepared via aromatic nucleophilic substitution according to the pseudo-high dilution principle. Small-size aromatic macrocycles were isolated by silica gel column chromatography with cyclohexane/ethyl acetate as eluent. The chemical structures of these small-size macrocycles were characterized by matrix-assisted laser desorption ionization–time-of-flight–mass spectrometry (MALDI–TOF–MS), IR, ¹⁹F-,¹H-, and ¹³C-NMR, and GPC techniques. Molecular chain length and steric hindrance of monomers affected the product compositions. The NMR results show that there are different chemical shifts in the different ring-size macrocyclic poly arylene ether ketones in spite of having the same repeating unit. The crystallizability and thermal properties of small-size arylene ether ketone macrocycles were also investigated by DSC, WAXD, TGA, and the results suggest that the crystallization and thermal properties are related to their intrinsic chemical structures. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1957–1967, 1999