Synthesis and properties of bioactive 2- and 3-amino-8-methyl-8H-quino[4,3,2-kl]acridine and 8,13-dimethyl-8H-quino[4,3,2-kl]acridinium salts

Cyclisation of 9-(benzotriazol-1-yl)acridine to the pentacycle 8H-quino[4,3,2-kl]acridine in a range of low-boiling solvents is mechanistically distinct from previously published photochemical (carbene) and thermolytic (radical) cyclisations. Fragmentation of the triazole ring of to a diazonium intermediate, and its subsequent heterolysis (-N(2)) and cyclisation is facilitated by solvation of intermediate zwitterionic species. Derivatives of 2- and 3-aminoquinoacridines methylated in the 8-position can be converted to 8,13-dimethylquino[4,3,2-kl]acridinium iodide salts with methyl iodide and were required for biological examination as potential telomerase inhibitors. The chloro group in 3-chloro-8-methyl-8H-quino[4,3,2-kl]acridine can be replaced efficiently by benzylamino, 4-morpholinyl and cyano substituents in palladium(0) mediated reactions.     

4-(2-羟基苯基)-亚胺基-戊-2-酮的晶体结构和谱学性质研究

通过邻氨基苯酚与乙酰丙酮反应,合成Schiff碱4-(2-羟基苯基)-亚胺基-戊-2-酮,获其单晶,测定晶体结构,用UV-Vis,IR,^HNMR谱对其进行了表征。其晶体属正交晶系,空间群P2~12~12~1,晶胞参数:a=0.8840(10)nm,b=1.05250(10)nm,c=1.12260(10)nm。V=1.0450(2)nm^3,Z=4,结构偏离因子R=0.0320,ωR=0.0669,吻合因子S=0.949存在较强的分子间氢键,O(1)与相邻分子的O(2)之间的平均距离为0.2640nm。晶体结构分析和谱学性质研究表明,化合物存在亚胺烯醇式和烯胺酮式两种异构平衡。     

Recognition Studies of a Pyridine-Pendant Calix[4]arene with Neutral Molecules: Effects of Non-covalent Interactions on Supramolecular Structures and Stabilities

A new calix[4]arene derivative containing hydrogen bond acceptors,5,11,17,23-tetra-tert-butyl-25,27-bis[(4-pyridylmethyl)oxy]-26,28-dihydroxycalix[4]arene (L), has been synthesized. ¹H-NMR titrations in chloroform-d werecarried out to investigate the host–guest chemistry ofL towards neutral molecules containing a widevariety of hydrogen bond donor groups such as aldehydederivatives of p-tert-butylcalix[4]arenes(compounds 3 and 4), acetylacetone,1,2-diaminoethane, 2,6-diaminopyridine, catechol,resorcinol, hydroquinone, phthalic acid, isophthalicacid and terephthalic acid. L can formcomplexes with resorcinol, phthalic acid and catecholin 1 : 1 (log K = 3.13), 1 : 1 (log K = 5.41) andpolymeric fashions, respectively. In addition, thesolution structures of these complexes have beenrevealed by NOESY experiments. L forms a 1 : 1complex with resorcinol by hydrogen bonding and vander Waals interactions resulting in a supramolecularframework. The phthalic acid molecule interacts withL via hydrogen bonding and is included into thelower rim cavity of L.     

对-二甲氨甲基杯[8]芳烃与DNA相互作用的紫外-可见光谱

被称为“第三代超分子化合物”的杯芳烃,是一类对位烷基苯酚与甲醛缩合的寡聚大环化合物,许多实验证实杯芳烃能通过超分子作用识别客体,这种方式类同于DNA与小分子的作用,     

一种苊并杂环有机小分子嵌入DNA的几何学模式研究

利用圆二色谱(CD)、紫外-可见吸收光谱以及荧光光谱等方法对苊并杂环化合物8-氧-8H-苊并[1,2-b]吡咯-9-腈(A1) 与小牛胸腺DNA(CT DNA) 的相互作用进行了研究. 结果表明, 随着n(A1)/n(CT DNA)的变化存在两种不同的几何学结合构型. 当n(A1)/n(CT DNA)值低于0.20时, A1分子与DNA的结合方式是不均一的, 化合物分子以多种角度嵌入到DNA碱基对之间. 表现为A1-DNA复合物的诱导圆二色光谱图上较小的正峰和紫外吸收光谱图缺省等吸收点. DNA的特征圆二色谱图表明, 在n(A1)/n(CT DNA)≤0.20范围内, CT DNA的构象从标准的B型转化为A-like型; 当n(A1)/n(CT DNA)>0.20时, 诱导圆二色光谱由正峰转变为强度大、波形复杂的负峰, 表明A1分子开始堆积到DNA螺旋的表面, 同时DNA的二级结构发生了进一步变化.     

A new oxime ligand in manganese chemistry: a [Mn8] and a [Mn6] cage from the use of 2-dihydroxy-2-phenylacetamidine

The use of phamidoxH(2) (phamidoxH(2) = 2-dihydroxy-2-phenylacetamidine) in manganese cluster chemistry led to the synthesis and characterization of a hexametallic and an octametallic Mn(III) cluster, both of which display a S = 3 ground state.     

[Ru(bpy)_2tpphz]~(2+)与Zn~(2+)形成的双核配合物的荧光性质研究

近年来,钌多吡啶配合物与DNA的作用得到了比较广泛的研究,并且发展了一系列具有特定功能的钌配合物犤1犦。如传统的DNA分子光开关犤Ru(bpy)2dppz犦2+和犤Ru(phen)2dppz犦2+犤2,3犦(bpy=2,2'-联吡啶,phen=1,10-菲咯啉,dppz=二吡啶犤3,2-a:2',3'-c犦吩嗪)。这些配合物与DNA具有较强的结合力,在水溶液中几乎不发光,但在DNA存在下则有强烈荧光发出。这是由于配合物插入DNA的碱基对之后,保护了dppz的吡嗪环上的N原子,使其免受水分子的进攻从而导致配合物荧光的恢复。但是对于大多数的多吡啶钌配合物来讲,由于其自身较强的背景荧光或与DN…     

含穿透配体Y—Y键的反夹心配合物[Y—C_8H_8—Y]~(2+)和L[Y—C_8H_8—Y]L (L=F,Cl,Br,I,Cp)的理论研究

对反夹心配合物[Y—C_8H_8—Y]~(2+)和L[Y—C_8H_8—Y]L(L=F,Cl,Br,I,Cp)进行了理论研究.计算结果表明,反夹心配合物的单态异构体为基态,异构化稳定性较好.[Y—C_8H_8—Y]~(2+)和L[Y—C_8H_8—Y]L(L=Cl,Br,I)中含有明显的穿透C_8H_8配体中心孔洞的Y—Y金属键,而在F[Y—C_8H_8—Y]F中Y—Y键较弱.此外,多层夹心配合物Cp[Y—C_8H_8—Y]Cp(Cp=C_5H_5)中也含有穿透中心配体的Y—Y金属键;另外,Y—Y键越强配合物的解离能越大,这种穿透配体的成键对于反夹心配合物的稳定性具有显著的贡献.     

Spectroelectrochemical Studies on the Interactions of Complexes of Cu(phen)_2~(2 ) and Cu(bpy)_2~(2 ) with DNA

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Binding Studies on the Control of the Conformation and Self-assembly of a Calix[4]arenedicarboxylic Acid through Hydrogen Bonding Interactions

A convenient method for measuring the dimerisation constant in solution of a calix[4]arenedicarboxylic acid is reported. This compound also co-crystallises with a bis(amidopyridyl)calix[4]arene as independent tubular calixarene stacks that are cross-linked via carboxyl–amidopyridyl hydrogen bonding and π-stacking of the amidopyridyl arms.     

Asymmetric Brønsted Base Catalyzed and Directed [3+2] Cycloaddition of 2‐Acyl Cycloheptatrienes with Azomethine Ylides

Conjugated cyclic trienes have the potential for different types of cycloaddition reactions. In the present work, we will, in a novel asymmetric cycloaddition reaction, demonstrate that the organocatalytic reaction of 2‐acyl cycloheptatrienes with azomethine ylides proceeds as a [3+2] cycloaddition, which is in contrast to the Lewis acid‐catalyzed reaction, in which a [3+6] cycloaddition takes place. In the presence of a chiral organosuperbase, 2‐acyl cycloheptatrienes react in a highly enantioselective manner in the [3+2] cycloaddition with azomethine ylides, providing the 1,3‐dipolar cycloaddition product in high yields and up to 99 % ee. It is also shown that the diene formed by the reaction can undergo stereoselective dihydroxylation, bromination, and cycloaddition reactions. Finally, based on experimental observations, some mechanistic considerations are discussed.     

Calix[4]Arene Cavitands: A Solid State Study on the Interactions of their Aromatic Cavity with Neutral Organic Guests Characterised by Acid CH3 or CH2 Groups

Abstract

To gain information on CH-π aromatic interactions involved in the formation of host-guest adducts, the geometrical parameters which define the solid state structures of the complexes of calix[4]arenes in the cone conformation with guests having acid CH₃ or CH₂ groups have been studied. Most of the data have been obtained from the CH₃CN and CH₂Cl₂ calix[4]arene complexes retrieved from the literature. To understand the effect of the acidity on these parameters, p-cyclohexylcalix[4]arene-biscrown-3 ? CH₃CN, p-tert-butylthiacalix[4]arene ? CH₃CN, p-tert-butylthiacalix[4]arene ? CH₃NO₂, 1,3-dipropoxy-p-tert-butylcalix[4]arene ? ClCH₂CN and 1,3-dipropoxy-p-tert-butylcalix[4]arene ? CH₂(CN)₂ complexes were prepared, crystallised and investigated in the solid state. CH₃X guests are bound preferentially by hosts having a C₄ symmetry. The interaction is directional, but it is independent from the basicity of the host and acidity of the guest, indicating that classic hydrogen bond do not play a major role. On the contrary CH₂XY guests find the best matching with hosts having a C_2v symmetry, interacting specifically with two diametrical aromatic rings. These interactions are directional and show a correlation between the acidity of the guest and the CH-π aromatic distance, thus supporting a stronger contribution of “classic” hydrogen bond in these latter complexes. These results are in agreement with the hypothesis that CH-π aromatic interactions derive from the superimposition of different types of intermolecular forces, whose contribution depends on several factors as the nature of the interacting partners.     

双核钼(O)配合物[(C2H5)4N]2[Mo2(CO)8(SCH2CO2(C2H5)2]的合成, 结构, 光谱和反应性能研究

Et4NI,NaSCH2CO2C2H5和Mo(CO)6在乙腈中反应制得一种新的双核钼(0)配合物[Et4N]2-[Mo2(CO)8(SCH2CO2Et)2](1), 电化学和反应性能研究指出1在电位～-0.43V发生一有趣的双电子一步氧化, 产生[Mo2(CO)8(SCH2CO2Et)2], 若氧化反应在配位溶剂中进行, 则其部分羰基被配位溶剂分子所取代成为[Mo2(CO)6(SCH2CO2Et)2L2](L=CH3CN).在1中, Mo…Mo不存在金属键以及MoS2Mo核骨架完全不同于氧化的产物Mo(I)配合物. 这结果完全证实了双电子一步转移是由于双金属中心的金属-金属键的形成或断裂伴随桥联双金属中心结构的重排而产生的推断.     

Studies on the Intramolecular Inclusion Complexes of Functionalized Calix[4]arenes with CH3X (X = CN,NO2)

Two functionalized calix[4]arenes in cone conformation L_2–3 have been synthesized and their intramolecular inclusion complexes (1:1) with organic neutral molecules CH₃CN and CH₃NO₂ have been prepared and characterized, respectively. The X‐ray crystallographic analysis shows that L₂ in L₂·CH₃CN. C₂H₅OH has C₄ symmestry and L₃ in L₃.CH₃NO₂ exhibits C₂ symmestry. The CH‐π aromatic interactions between the CH group of the guest and the phenyl rings of the calix backbond have been proved to be able to stabilize the intramolecular inclusion complexes formed. The interaction is directional, but it is independent of the acidity of the guest. To gain information on CH‐s interactions, suitable geometrical parameters have been calculated from the crystal data of intramolecular inclusion complexes. The results show that L₃.CH₃NO₂ with L₃ in C₂ symmestry can also be bound stably in the intramolecular inclusion complex, being consistent with the thermal analysis. The geometrical parameters and the results of the thermal analysis of L₁.CH₃CN and L₁.CH₃NO₂ were also given and discussed.     

[Ru(bpy)2tpphz]2+与Zn2+形成的双核配合物的荧光性质研究

The formation of heterobimetallic ruthenium(Ⅱ) complex was investigated by absorption and emission spectra. As an intercalator of DNA， the luminescent monometallic ruthenium(Ⅱ) complex [Ru(bpy)₂tpphz]²⁺ could coor-dinate with Zn²⁺ to form the nonluminescent heterobimetallic complex [Ru(bpy)₂(tpphz)Zn]⁴⁺. The emission in-tensity of complex decreased as increasing the amounts of Zn²⁺ and the luminescence was almost lost at the ratio of [Zn]/[Ru] of 1. After binding to DNA， the peripheral coordination site on the tpphz ligand remained accessible for Zn²⁺， the coordination occurred from the oppsite side of helix with respect to intercalated [Ru(bpy)₂tpphz]²⁺ and the nonluminescent heterobimetallic complex was formed. On the other hand， the [Ru(bpy)₂(tpphz)Zn]⁴⁺ also bound to DNA by intercalation and situated the region of the intercalated [Ru(bpy)₂tpphz]²⁺ between the base pairs of DNA. The complex looked like a molecular nut (the Zn²⁺) and bolt (the [Ru(bpy)₂tpphz]²⁺).     

Studies on the chromatographic behavior of nucleosides and bases on p-tert-butyl-calix[8]arene-bonded silica gel stationary phase by HPLC

The chromatographic behavior of some nucleosides, pyrimidines and purines on a new p-tert-butyl-calix[8]arene-bonded silica gel stationary phase (CABS) were studied by high performance liquid chromatography. Their retention behavior on CABS were compared with those on ODS. The influence of mobile phase variables, such as methanol content, pH and ionic strength on the retention behavior were studied. Some nucleosides, pyrimidines and purines on CABS were successfully separated. The results show that the calix[8]arene-bonded phase exhibits high selectivities for the above analytes in high aqueous mobile phases. According to the chromatographic data, it is indicated that hydrophobic interaction, hydrogen-bonding interaction, and dipole-dipole interaction are mainly responsible for the retention behavior. In addition, in some extent, the vertical stacking action of the analytes on CABS can also change the retention behavior. CABS was superior to ODS in the routine fast separation of nucleosides and bases.     

Studies on the pauson-khand reaction. Exclusive formation of angularly fused triquinanes from bicyclo[3.3.0]oct-2-ene and propargyl derivatives

Reaction of bicyclo[3.3.0]oct-2-ene with different hexacarbonyl dicobalt complexes of propargyl derivatives leads, under a great variety of experimental conditions, to the exclusive formation of angularly fused triquinanes, the corresponding reduced products being formed if the reaction is run at high temperature. The intermediacy of a π-allyl complex is suggested in order to account for these results, as well as for the presence of minor amounts of Diels-Alder adducts in the reaction mixture.