One-electron reduction of an "extended viologen" p-phenylene-bis-4,4'-(1-aryl-2,6-diphenylpyridinium) dication

One-electron reduction of the "extended viologen" dication 1 yields the red cation radical 2, characterized by strong near-IR absorption. It has been generated and studied by pulse radiolytic, electrochemical, redox titration, UV-visible, and electron paramagnetic resonance spectroscopic methods. All results are in agreement with a fully delocalized electronic structure for 2.     

Nonaqueous capillary electrophoretic assays of p-phenylene-bis-4,4'-(1-aryl-2,6-diphenylpyridinium) molecular wires

A nonaqueous CE system for separation and detection of novel electron-dopable molecular wires based on p-phenylene-bis-4,4'-(1-aryl-2,6-diphenylpyridinium) oligomers is described. The method is based on the coupling of CE separation in pure organic solvent, DMF with 50 mM acetic acid, and UV detection at 338 nm. The system offers a rapid measurement in less than 20 min for two priority nanowires and their impurities. Calibration data confirmed linear response for all compounds of interest in the concentration range 0.1-1.0 mg/mL. A highly stable response was observed for repetitive injections (RSD < or = 2.8%, n = 10).     

Synthesis and characterization of a highly reducing neutral "extended viologen" and the isostructural hydrocarbon 4,4''''-di-n-octyl-p-quaterphenyl

The molecule 4,4'-di-n-octyl-p-quaterphenyl was synthesized in one step by a nickel-catalyzed cross-coupling reaction. Powder X-ray diffraction shows that it crystallizes in a layered structure with the long axis of the molecule nearly perpendicular to the layer plane. Differential scanning calorimetry indicates a transition to a liquid-crystalline phase at 81 degrees C. Reaction of 4,4'-bis(4-pyridyl)biphenyl with 1-bromooctane yields the dication 2(2+) 2Br-, an "extended viologen" isostructural with 4,4'-di-n-octyl-p-quaterphenyl. Reduction of 2(2+) 2Br- with sodium amalgam in DMF yields 2, the first neutral extended viologen to be isolated. The molecule 2 is, to the best of our knowledge, the most reducing neutral organic molecule that has been synthesized. Single-crystal X-ray diffraction shows that a diradical form, either singlet or triplet, makes an important contribution to the electronic structure of 2. The broadened 1H NMR spectrum of 2 indicates the presence of a triplet, but it has not been possible to observe the triplet by ESR spectroscopy. The electronic structure of 2 appears to be closely related to that of a classic molecule, Chichibabin's hydrocarbon.     

First synthesis of 1-aryl-4,4-dichlorobut-3-en-1-ones. The electrochemical reduction of 1-aryl-4,4,4-trichlorobut-2-en-1-ones as a key step

The first method for the synthesis of 1-aryl-4,4-dichlorobut-3-en-1-ones is reported. Treatment of acetophenones with anhydrous chloral leads to 1-aryl-4,4,4-trichloro-3-hydroxybutan-1-ones in near quantitative yields. These compounds were efficiently dehydrated with either sulfuric or p-toluenesulfonic acid to give 1-aryl-4,4,4-trichlorobut-2-en-1-ones, which were selectively converted to the title compounds in fair to quantitative yields by electrochemical reduction. The X-ray crystallographic structure of 4,4-dichloro-1-(4-methoxyphenyl)but-3-en-1-one has been determined. The preferential formation of β,γ-unsaturated ketones with total exclusion of the corresponding α,β-unsaturated isomers has been discussed with the aid of HF and B3LYP density functional theory methods.     

Synthesis, modeling and evaluation of 3'-(1-aryl-1H-tetrazol-5-ylamino)-substituted 3'-deoxythymidine derivatives as potent and selective human mitochondrial thymidine kinase inhibitors

Based on the presumed binding mode of an earlier identified inhibitor, we herein report new 3'-modified nucleosides as potent and selective inhibitors of mitochondrial thymidine kinase (TK2). A series of thirteen 3'-amino-, 3'-guanidino- and 3'-tetrazole-containing nucleosides were synthesized and evaluated for their TK2 inhibitory activity. Within the tetrazole series, compounds with nanomolar inhibitory activity were identified. A homology model of TK2 allowed to elucidate the observed activities. Introduction of a 2-bromovinyl group on C-5 of the pyrimidine base of the most promising 3'-derivative further improved the inhibitory activity, and caused a significant increase in the selectivity for TK2 versus TK1. Interestingly, for the current series of analogues, a strong correlation was observed between TK2 and Drosophila melanogaster dNK inhibition, further substantiating the phylogenetic relationship between these two nucleoside kinases.     

New method for the synthesis of 6-amino-4-aryl-3,5-dicyano-3,4-dihydropyridine-2(1H)-thiones by recyclization of 4-aryl-2,6-diamino-4H-thiopyranes

Ammonium 6-amino-4-aryl-3,5-dicyano-1,4-dihydropyridine-2-thiolates were synthesized by recyclization of 4-aryl-2,6-diamino-3,5-dicyano-4H-thiopyranes in the presence of organic bases. On acidification of the products, the corresponding substituted 3,4-dihydropyridine-2(1H)-thiones were obtained which were used in the synthesis of 2-alkylthio-1,4-dihydropyridines, bis-(pyridyl-2)disulfides and thieno[2,3-b]pyridines.Deceased.T. G. Shevchenko Lugansk State Pedagogical Institute, Lugansk 348011. N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 117913. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 909–914, July, 1997.     

((3-(3-硅胶丙基)硫基)丙基)硫酸酯作为可回收催化剂用于合成4,4'-芳亚甲基-双(1H-吡唑-5-醇)(英文)

Sulfuric acid ([3-(3-silicapropyl)sulfanyl]propyl)ester is employed as a recyclable catalyst for the condensation reaction between aromatic aldehydes and 3-methyl-l-phenyl-5-pyrazolone. This condensation reaction was performed in ethanol under refluxing conditions giving 4,4'-alkylmethylene-bis(3-methyl-5-pyrazolones) in 74-90% yields. The heterogeneous catalyst was recycled and used in eleven runs for the reaction between benzaldehyde and 3-methyl-l-phenyl-5-pyrazolone without losing catalytic activity.     

Syntheses, structural characterization and properties of transition metal complexes of 5,5'-(1,4-phenylene)bis(1H-tetrazole) (H(2)bdt), 5',5'-(1,1'-biphenyl)-4,4'-diylbis(1H-tetrazole) (H(2)dbdt) and 5,5',5'-(1,3,5-phenylene)tris(1H-tetrazole) (H(3)btt)

The hydrothermal chemistry of a variety of M(II)SO(4) salts with the tetrazole (Ht) ligands 5,5'-(1,4-phenylene)bis(1H-tetrazole) (H(2)bdt), 5',5'-(1,1'-biphenyl)4,4'-diylbis(1H-tetrazole) (H(2)dbdt) and 5,5',5'-(1,3,5-phenylene)tris(1H-tetrazole) (H(3)btt) was investigated. In the case of Co(II), three phases were isolated, two of which incorporated sulfate: [Co(5)F(2)(dbdt)(4)(H(2)O)(6)]·2H(2)O (1·2H(2)O), [Co(4)(OH)(2)(SO(4))(bdt)(2)(H(2)O)(4)] (2) and [Co(3)(OH)(SO(4))(btt)(H(2)O)(4)]·3H(2)O (3·3H(2)O). The structures are three-dimensional and consist of cluster-based secondary building units: the pentanuclear {Co(5)F(2)(tetrazolate)(8)(H(2)O)(6)}, the tetranuclear {Co(4)(OH)(2)(SO(4))(2)(tetrazolate)(6)}(4-), and the trinuclear {Co(3)(μ(3)-OH)(SO(4))(2) (tetrazolate)(3)}(2-) for 1, 2, and 3, respectively. The Ni(II) analogue [Ni(2)(H(0.67)bdt)(3)]·10.5H(2)O (4·10.5H(2)O) is isomorphous with a fourth cobalt phase, the previously reported [Co(2)(H(0.67)bat)(3)]·20H(2)O and exhibits a {M(tetrazolate)(3/2)}(∞) chain as the fundamental building block. The dense three-dimensional structure of [Zn(bdt)] (5) consists of {ZnN(4)}tetrahedra linked through bdt ligands bonding through N1,N3 donors at either tetrazolate terminus. In contrast to the hydrothermal synthesis of 1-5, the Cd(II) material (Me(2)NH(2))(3)[Cd(12)Cl(3)(btt)(8)(DMF)(12)]·xDMF·yMeOH (DMF = dimethylformamide; x = ca. 12, y = ca. 5) was prepared in DMF/methanol. The structure is constructed from the linking of {Cd(4)Cl(tetrazolate)(8)(DMF)(4)}(1-) secondary building units to produce an open-framework material exhibiting 66.5% void volume. The magnetic properties of the Co(II) series are reflective of the structural building units.     

Synthesis,Structure, and Biological Activity of Magnesium(II), Zinc(II), Cobalt(II), and Copper(II) Bis(4-aryl-1-ethoxy-1-oxobutane-2,4-dionates)

Russian Journal of General Chemistry - The condensation of aryl methyl ketones with diethyl oxalate in the presence of metallic sodium or sodium hydride gave sodium...     

2,6-二[4-′(N,N-二苯基氨基)芪]苯并[1-2,4-5]二噁唑的合成与发光特性

通过对二苯氨基苯甲醛与2,6-二(4-氯甲基苯基)苯并[1-2,4-5]二唑之间的Wittig-Horner反应,设计并合成了一个2,6-二[4-′(N,N-二苯基氨基)芪]苯并[1-2,4-5]二唑新化合物,目的在于均二苯乙烯分子中同时引入空穴传输和电子传输结构单元,可望提高均二苯乙烯型发光材料的发光强度和光量子效率.采用UV-VisI、R1、HNMR和元素分析等分析方法对合成产物结构进行了确认,并考察了溶剂对其光致发光特性的影响.所合成化合物的相关分析数据表明:1)其分子中的两个均二苯乙烯基均为反式“芪”结构特征;2)随溶剂极性增高,其UV-Vis光谱和荧光光谱的λmax红移;3)可用作蓝色发光材料.     

Reaction of 5,5'-(1,4-Phenylene)bis(3-aryl-2-oxaspiro[5.5]undec-3-en-1-ones) with Methyl 1-Bromocyclohexanecarboxylate and Zinc

Russian Journal of Organic Chemistry - The reaction of 3,3'-(1,4-phenylene)bis(1-phenylprop-2-en-1-ones) with the Reformatsky reagent obtained from methyl 1-bromocyclohexanecarboxylate and zinc...     

Complexes of 2,6-Disubstituted 1-Oxa-4-thia-3,5-diazine 4,4-Dioxides with Symmetric Triazines as Supramolecular Systems. Preparation and Properties

Reactions of 2,6-disubstituted 1-oxa-4-thia-3,5-diazine 4,4-dioxides with substituted cyanamides in aromatic solvents (benzene, toluene, chlorobenzene, benzonitrile) furnished stable complexes including 1-oxa-4-thia-3,5-diazine4,4-dioxide, symmetric triazine, and solvent (or no solvent) in a ratio 2 : 2 : 1. The molecules involved in the complexes are joined by intramolecular forces into a unified energetically favorable supramolecular system.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 2, 2005, pp. 297–300.Original Russian Text Copyright © 2005 by Shishulina, Sazhina, Michurin.     

Synthesis and antiarrhythmic activity of 2,2-dialkyl-1'-(N-substituted aminoalkyl)-spiro-(chroman-4,4'-imidazolidine)-2',5'-diones.

A novel series of 2,2-dialkyl-1'-(N-substituted aminoalkyl)-spiro-[chroman-4,4' -imidazolidine]-2',5'-diones was synthesized and evaluated for antiarrhythmic activity in chloroform- or/and aconitine-induced ventricular arrhythmia in mice. Among these compounds, (-)-6-chloro-2,2-dimethyl-1'-[3-(4-hydroxypiperidino)propyl] -spiro-[chroman-4,4'-imidazolidine]-2',5' -dione was found to be more effective than reference agents and was selected for further development.     

Computational analysis of aza analogues of [2',5'-bis-O-(tert-butyldimethylsilyl)-beta-D-ribofuranose]-3'-spiro-5"-(4"-amino-1",2"-oxathiole-2",2"-dioxide) (TSAO) as HIV-1 reverse transcriptase inhibitors: relevance of conformational properties on the inhibitory activity

We have carried out a theoretical analysis of aza analogues of [2',5'-bis-O-(tert-butyldimethylsilyl)-beta-D-ribofuranosyl]-3'-spiro-5"-(4"-amino-1",2"-oxathiole-2",2"-dioxide) by a variety of computational tools, aimed to account for the effect of the endocyclic amino moiety N-2" on the inhibitory activity against HIV-1. Docking studies suggest that compounds substituted at the N-3 and N-2' ' positions present the same binding mode to the [2',5'-bis-O-(tert-butyldimethylsilyl)-beta-D-ribofuranosyl]-3'-spiro-5"-(4"-amino-1",2"-oxathiole-2",2"-dioxide)thymine prototype, where the endocyclic amino group remains mostly exposed to the solvent. A careful conformational analysis performed through different theoretical levels, from molecular mechanics to high-level quantum mechanical calculations, provides a rationalization based on conformational preferences, which appears as strongly determined by the substitution at N-2", and on electrostatic effects from the bulk water.     

Physicochemical study of binuclear copper(II), oxovanadium(IV), and iron(III) complexes with bis-1′-phthalazinylhydrazone of 2,6-diformyl-4-tert-butylphenol

Binuclear copper(II), oxovanadium(IV), and iron(III) complexes with bis-1′-phthalazinylhydrazone of 2,6-diformyl-4-tert-butylphenol have been prepared. An antiferromegnetic exchange interaction between the paramagnetic centers was found. Redox properties of the complexes were studied by the methods of cyclic and differential pulse voltammetry; the reduction of Cu(II) complexes was shown to proceed in two consecutive one-electron steps.     

Simple and efficient synthesis of 2,6-dialkyl-3,5-dialkoxycarbonyl-4-(3-aryl-1-phenyl-pyrazol-4-yl)pyridines using TPAP/NMO as a catalyst under mild conditions

Biologically important pyrazolylpyridines were synthesized in excellent yield by the oxidation of pyrazolyl 1,4-dihydropyridines (pyrazolyl 1,4-DHPs) using tetrapropylammonium perruthenate/N-methylmorpholine-N-oxide (TPAP/NMO) under mild conditions at 0 °C.