1-Ethyl-1,4-dihydro-4-oxo-7-(pyridinyl)-3-quinolinecarboxylic acids. I. Synthesis of 3- and 4-(3-aminophenyl)pyridine intermediates

A series of substituted 3- and 4-(3-aminophenyl)pyridines has been prepared as intermediates for the synthesis of some 1-alkyl-1,4-dihydro-4-oxo-7-pyridinyl-3-quinolinecarboxylic acids. The Hantzsch, Hauser and other pyridine syntheses were used. 4-(3-Aminophenyl)pyridine was prepared via 3-(4-pyridinyl)-2-cyclohexen-1-one using the Semmler-Wolff reaction.     

Oxidative opening of the 2,5-dihydroxy-3,4,6,7-tetrachlorocoumaran ring

A method has been developed for the synthesis of (3,5,6-trichloro-1,4-benzoquinone-2-yl)chloroacetaldehyde by the oxidative ring opening of 2,5-dihydroxy-3,4,6,7-tetrachlorocoumaran with nitrogen oxides. The ion-radical salt of (3,5,6-trichloro-1,4-benzoquinone-2-yl)chloroacetaldehyde with N,N,N,N-tetramethyl-p-phenylenediamine (11) has been synthesized. The reaction of 2,5-dihydroxy-3,4,6,7-tetrachlorocoumaran-3-yl) with pyridine gave N-(2,5-dihydroxy-4,6,7-trichlorocoumaran-3-yl)pyridine chloride, which is also formed from the opening of the coumaran ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 892–895, July, 1990.     

Structural and spectral investigation on the Co complexes with 1,4-diazacycloheptane (DACH) functionalized by heterocyclic pendants

A series of penta-coordinated Co^II complexes of 1,4-diazacycloheptane (DACH) functionalized by additional imidazole or pyridine donor pendants, [CoL¹Cl](ClO₄)·H₂O (1), [CoL²Cl](ClO₄) (2) and [CoL³Cl](ClO₄)·CH₃OH (3), where L¹=1,4-bis(imidazole-4-ylmethyl)-DACH, L²=1,4-bis(N-1-methylimidazol-2-ylmethyl)-DACH and L³=1,4-bis(pyridyl-2-ylmethyl)-DACH have been synthesized and characterized by elemental analyses, IR and UV–Vis spectra. In all the mononuclear complexes, each Co^II center is penta-coordinated to four nitrogen donors of the ligand and one axial chloride anion. The crystal structure of complex 2 has been determined by X-ray diffraction analysis, which forms a one-dimensional linear structure through inter-molecular C–HCl and C–HO hydrogen-bonding.     

Investigation of heterocycles containing nitrogen or sulfur. 48. Derivatives of 1-morpholinooxalyl-1,2-dihydrothiazolo-[5,4-b]pyridine,their structure,and reactions

The structures of the products of reactions of 1-N-morpholinooxahi-1,2-dihydrothiazolo-[5,4-b]pyridine have been studied by IR, NMR, UV, and mass spectroscopy. Geometric (cis-anti) and rotational (about the CO-N amide bond) isomers of 1-N-morpholinooxalyl-2-propionyi-5-chloro-1,2-dihydrothiazolo-[5,4-b]pyridine oxime have been observed and studied. Treatment of 1-N-morpholinooxalyl-2-propionyl-5-chloro-1,2-dihydrothiazolo[5,4-b]pyridine with ethanolic alkali gave 2-propionyl-5-chlorothiazolo-[5,4-b]pyridine, while treatment with concentrated H₂SO₄ gave 1,2-dioxo-ethylidene-7-chloroxazolidino[3,2-f]pyrido[2,3-b]1,4-thiazine.For Communication 47 see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1133–1138, August, 1993.     

Investigation of heterocycles containing nitrogen or sulfur. 47. Reactions of 1,2-dioxo-3a-alkyl-4,7-dichloroxazolidino [3,2-f]pyrido[2,3-b]-1,4-thiazines with saturated cyclic amines. synthesis and structure of derivatives of 1,2-dihydrothiazolo[5,4-b]pyridine

It has been established spectroscopically that 1-N-oxalamides of 2-acyl-5-chloro-1,2-dihydrothiazolo[5,4-b] pyridine are formed in the reaction of 4,7-dichloroxazolidino[3,2-f]pyrido[2,3-b]-1,4-thiazines with morpholine, piperidine and pyrrolidine. The products are a mixture of amide conformers in solution. The reaction intermediate 2-(1-chloro-2-oxobutylthio)-3-pyrrolidinooxamoyl-6-chloropyridine has been isolated and characterized. A proposed reaction scheme is presented.For Communication 46 see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1125–1132, August, 1993.     

An umpolung approach to the hydroboration of pyridines: a novel and efficient synthesis of N-H 1,4-dihydropyridines

The first inverse hydroboration of pyridine with a diboron(4) compound and a proton source has been realized under simple basic and catalyst-free conditions. This process consists of a formal boryl anion addition to pyridine, which produces an N-boryl pyridyl anion complex, and the subsequent protonation of the anion complex. This process enables a simple and efficient method for the synthesis of multi-substituted N-H 1,4-dihydropyridine (1,4-DHP) derivatives that are difficult to prepare using established methods. Furthermore, this method allows for facile preparation of 4-deuterated 1,4-DHPs from an easily accessible deuterium ion source. This inverse hydroboration reaction represents a new mode for pyridine functionalization.

Umpolung of pyridine hydroboration was achieved by the reaction between pyridine and diboron(4) with a base and a proton source.     

Some nitro derivatives of 1,4-benzodioxino[2,3-b]pyridine. Crystal and molecular structure of 2,7,8-trinitro-1,4-benzodioxino[2,3-b]pyridine

The electrophilic nitration of 1,4-benzodioxino[2,3-b]pyridine 1 with nitric acid in sulfuric acid has been studied. Some of the products of nitration including 7 - and 8 -nitro derivatives 2a and 2b , respectively, 7,9-, 7,8- and 6,8-dinitro derivatives 3a , 3b and 3c , respectively, and 2,7,8-trinitro derivative 4 have been isolated and characterized. The structure of isomers have been assigned for derivatives 3b and 4 while tentative structures have been proposed for the other products. The cyclopentadienyliron complex of 1 gives the same reaction products under similar conditions while for some other milder nitrating reagents no reaction was observed. 2,7,8-Trinitro-1,4-benzodioxino[2,3-b]pyridine 4 crystallizes in the monoclinic system, space group P2₁/c; the dihedral angle between the planes of outer rings was found to be 174.65(8) degrees. The planes of the nitro groups have been found to be rotated with respect to the appropriate pyri-dine and benzene ring planes by 11.13(11) degrees for the 2-nitro group and 47.56(9) and 29.80(9) degrees for the 7-nitro and 8-nitro groups, respectively.     

Synthesis and some heterocyclization reactions of new diethyl (1,1-difluoro-3,3-dicyano-2-trifluoromethylallyl)phosphonate and ethyl 3,3-dicyano-2-[(diethoxyphosphoryl)difluoromethyl]acrylate

A new CF₂X-analogue of 1,1-bis(trifluoromethyl)-2,2-dicyanoethylene (X = P(O)(OEt)₂), diethyl (1,1-difluoro-3,3-dicyano-2-trifluoromethylallyl)phosphonate, has been synthesized from diethoxyphosphoryl pentafluoroacetone 1. A similar phosphoryl analogue of ethyl 3,3-dicyano-2-trifluoromethylacrylate, ethyl 3,3-dicyano-2-[(diethoxyphosphoryl)difluoromethyl]acrylate, has been obtained from ethyl 3-(diethoxyphosphoryl)-3,3-difluoro-2-oxopropionate 2. By heterocyclization of these new ethylenes with 3-methyl-2-pyrazoline-5-ones, 3(5)-aminopyrazoles, dimedone, 2-aminopyridines, 1-aryl-3-methyl-5-aminopyrazoles, 1,3,3-trimethylisoquinolines, as well as by condensation with anilines and ketones, the difluoromethylphosphonate-substituted derivatives of 1,4-dihydropyrano[2,3-c]pyrazole, 4,5-dihydropyrazolo[1,5-a]pyrimidine, 5,6,7,8-tetrahydro-4H-chromene, 2H-pyrido[1,2-a]pyrimidine, 4,7-dihydro-1H-pyrazolo[3,4-b]pyridine, 1,4-dihydropyridine, 4,5,6,7-tetrahydro-1H-[1]pyrindine, 1,4,5,6,7,8-hexahydroquinoline, and 6,7-dihydro-2H-pyrido[2,1-a]isoquinoline have been obtained in one stage.     

Snapshots of a metamorphosing Cu(II) ground state in a galactose oxidase-inspired complex

The novel ligand 2,6-bis[S-(3,5-di-tert-butyl-2-hydroxyphenyl)sulfanylmethyl]pyridine (H(2)L1) and its copper(II) complex Cu(L1), 1, were synthesized with the aim of constructing a model of the active site of the enzyme galactose oxidase (GOase). Cyclic voltammetry studies show that 1 undergoes ligand-based quasi-reversible oxidations (phenolate/phenoxyl) and reversible metal-based reduction [copper(II)/copper(I)] similar to those of GOase, but at potentials much higher and lower, respectively, than those found for the enzyme. At room temperature, spectrophotometric titrations show that 1 binds strongly to 1 equiv of pyridine. In frozen solutions (77 K), 1 quantitatively binds both pyridine and ethers (e.g., 1,4-dioxane) as assessed by X- and Q-band EPR spectroscopy. Profound shifts in the pattern of g values result, from rhombic (g(1) > g(2) > g(3)) in toluene to either inverted axial patterns (g(1) = g(2) > g(3)) in the presence of ethers or a near-axial pattern (g(1) > g(2) > g(3)) in the presence of pyridine. Crystallographic analyses of the parent complex 1.MeCN, the dioxane-bridged dimer [(Cu(L1))(2)((mu-1,4)-1,4-dioxane)].(Me(2)CO)(2) (2), and the pyridine complex [Cu(L1)(pyridine)] (3) show that the pyridine and ether ligands bond to copper at a sixth octahedral position left vacant by the pentadentate NO(2)S(2) coordination mode of L1(2-) and induce perturbations of its geometry. Hybrid DFT calculations based on the crystallographic coordinates combined with perturbation theory expressions for the g values of a d(9) system correlate the results from EPR spectroscopy to the proportions of d(x)(2)(-)(y)(2) and d(z)(2) character in the relevant copper-centered unoccupied molecular orbital. The combination of spectroscopic, structural, and computational results for this set of copper(II) complexes provides a demonstrative example of the physical phenomena underlying rhombic EPR spectra of d(9) systems.     

Bivalent and trivalent iron complexes of acyclic hexadentate ligands providing pyridyl/pyrazine-amide-thioether coordination

Acyclic pyridine-2-carboxamide- and thioether-containing hexadentate ligand 1,4-bis[o-(pyridine-2-carboxamidophenyl)]-1,4-dithiobutane (H(2)bpctb), in its deprotonated form, has afforded purple low-spin (S = 0) iron(II) complex [Fe(bpctb)] (1). A new ligand, the pyrazine derivative of H(2)bpctb, 1,4-bis[o-(pyrazine-2-carboxamidophenyl)]-1,4-dithiobutane (H(2)bpzctb), has been synthesized which has furnished the isolation of purple iron(II) complex [Fe(bpzctb)].CH(2)Cl(2) (4) (S = 0). Chemical oxidation of 1 by [(eta(5)-C(5)H(5))(2)Fe][PF(6)] or [Ce(NO(3))(6)][NH(4)](2) led to the isolation of low-spin (S = 1/2) green Fe(III) complexes [Fe(bpctb)][PF(6)] (2) or [Fe(bpctb)][NO(3)].H(2)O (3), and oxidation of 4 by [Ce(NO(3))(6)][NH(4)](2) afforded [Fe(bpzctb)][NO(3)].H(2)O (5) (S = 1/2). X-ray crystal structures of 1 and 4 revealed that (i) in each case the ligand coordinates in a hexadentate mode and (ii) bpzctb(2-) binds more strongly than bpctb(2-), affording distorted octahedral M(II)N(2)(pyridine/pyrazine)N'(2)(amide)S(2)(thioether) coordination. To the best of our knowledge, 1 and 4 are the first examples of six-coordinate low-spin Fe(II) complexes of deprotonated pyridine/pyrazine amide ligands having appended thioether functionality. The Fe(III) complexes display rhombic EPR spectra. Each complex exhibits in CH(2)Cl(2)/MeCN a reversible to quasireversible cyclic voltammetric response, corresponding to the Fe(III)-Fe(II) redox process. The E(1/2) value of 4 is more anodic by approximately 0.2 V than that of 1, attesting that compared to pyridine, pyrazine is a better stabilizer of iron(II). Moreover, the E(1/2) value of 1 is significantly higher (approximately 1.5 V) than that reported for six-coordinate Fe(II)/Fe(III) complexes of the tridentate pyridine-2-carboxamide ligand incorporating thiolate donor site.     

Preparation of Pseudo-Arsonolipids: Dl-2,3-Diacyloxybutane-1,4-Bis(Arsonic Acids)

Abstract

The title pseudo-arsonolipid with palmitoyl side chain has been prepared in ～70% yield from its parent DL-2,3-dihydroxybutane-1,4-bis(arsonic acid) after reduction of the As(V) to As(III) by thiophenol, acylation with palmitoyl chloride in the presence of pyridine and catalytic amounts of 4-(dimethylamino)pyridine, and reoxidation of As(III) to As(V) by hydrogen peroxide. In CDCl₃/CD₃OD esterification of the –AsO₃H₂ groups was detected by ¹H NMR.     

吡啶桥联的聚酰亚胺的合成与性能研究

以3,4-二甲基苯乙酮与3,5-双(三氟甲基)苯甲醛为原料,通过Chichibabin反应制备了吡啶桥联的四甲基化合物,该化合物再经氧化、脱水反应制备了主链含有吡啶环、侧链带有双三氟甲基取代苯侧基的新型含氟芳香族二酐单体,2,6双(3′,4′-二羧基苯基)-4-(3″-,5″-双三氟甲基苯基)吡啶二酐(6FDAPA).FT IR、NMR、质谱以及元素分析等测试结果表明,6FDAPA的结构与预期的相符.利用6FDAPA与另外一种不含氟的二酐单体2,6双(3′,4′二羧基苯基)4苯基吡啶二酐(DAPA)分别与含氟二胺单体,1,4双(2三氟甲基4氨基苯氧基)苯(6FAPB)通过两步热亚胺化法制备了两种聚酰亚胺(PI)薄膜.测试结果表明,6FDAPA6FAPB(PI2)与DAPA6FAPB(PI1)相比具有相近的耐热性能,玻璃化转变温度为280℃,起始热分解温度为580℃、700℃时的重量保持率64.5%.同时PI2具有更为优良的透光性,紫外可见光谱(UV Vis)测试表明,PI2与PI1薄膜在450nm处的透光率分别为85.7%与69.4%.     

Highly selective and turn-on fluorescence probe with red shift emission for naked-eye detecting Al3+ and Ga3+ based on metal-organic framework

A novel ZnⅡ-based metal-organic framework with the formula of {[Zn2(BBIP)2(NDC)2]·H2O}n (JXUST-5)derived from 3,5-bis(benzimidazol-1-yl)pyridine (BBIP) and 1,4-...     

Synthesis of Quaternized poly(4-Vinyl Pyridine) and the Study of its Ion Exchange Property

Lightly cross-linked poly(4-vinyl pyridine) has been synthesized from 4-vinyl pyridine and a small amount of ethylene glycol dimethacrylate (EGDMA) in aqueous medium through micelle technique. The polymer is then quaternized with 1,4-dibromobutane to develop an anion exchange resin with high selectivity and ion exchange capacity at a wide range of pH and temperature. The material exhibits high ion exchange capacity and reverse anion selectivity order compared to commercially available anion exchanger. A method has been designed to separate chromate and sulfate using the synthesized material.     

Effect of the solvent nature on the course of quaternization of 3,5-diethoxycarbonyl-2,6-dimethyl-4-(3-pyridyl)-1,4-dihydropyridine

The effect of the solvent nature and temperature on the quaternization of 3,5-diethoxycarbonyl-2,6-di- methyl-4-(3-pyridyl)-1,4-dihydropyridine by lipophilic alkyl bromides has been investigated. By comparison of the solvent effect (acetone, acetonitrile, and 2-butanone) on the alkylation of the pyridine fragment of 3,5-diethoxycarbonyl-2,6-dimethyl-4-(3-pyridyl)-1,4-dihydropyridine it was established that conducting the reaction in acetonitrile at 81 °C is the most optimal.     

Binuclear ruthenium macrocycles formed via the weak-link approach

The "weak-link approach" for the synthesis of metallomacrocycles has been used to synthesize a series of novel Ru(II) macrocycles in high yield. RuCl2(PPh3)3 has been reacted with two different phosphino-alkyl-ether hemilabile ligands, 1,4-(PPh2(CH2)2O)2C6H4 and 1,4-(PPh2(CH2)2OCH2)2C6H4. The hemilabile bidentate ligand coordinates to Ru(II) centers through both the P and O atoms to form bimetallic "condensed intermediates". The weak Ru-O bonds have been selectively cleaved with CO, 1,2-diaminopropane, and pyridine to yield large open macrocycles. This is the first example of the weak-link approach employed to synthesize macrocycles with Ru, and metal centers in general that have more than four coordination sites.     

Reaction of diketene with cyanothioacetamide: A convenient and regioselective method for the preparation of new 4(1H)-pyridone derivatives

The reaction of diketene with cyanothioacetamide in dry dioxane in the presence of triethylamine gives triethylammonium 3-cyano-6-methyl-4-oxo-1,4-dihydro-2-pyridinethiolate. The regioselective S-alkylation of this thiolate is a convenient method for the preparation of substituted 4(1H)-pyridones and also derivatives of thiazolo[3,2-a]pyridine and thieno[2,3-b]pyridine. The action of 2-amino-1,1,3-tricyanopropene on this thiolate leads to its transformation into a new heterocyclic system, namely, 5H-pyrido[2′,3′:4,5]thiopyrano[2,3-b]pyridine; treatment with iodine yields the oxidation product, namely, the corresponding bis(2-pyridyl) disulfide. The structure of isopropyl (3-cyano-6-methyl-4-oxo-1,4-dihydro-2-pyridinyl)thioacetate was confirmed by X-ray diffraction structural analysis. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 716–725, May, 2007.     

Structure and properties of bivalent nickel and copper complexes with pyrazine-amide-thioether coordination: stabilization of trivalent nickel

Acyclic pyrazine-2-carboxamide and thioether containing hexadentate ligand 1,4-bis[o-(pyrazine-2-carboxamidophenyl)]-1,4-dithiobutane (H(2)bpzctb), in its deprotonated form, has afforded light brown [Ni(II)(bpzctb)](1)(S=1) and green [Cu(II)(bpzctb)](2)(S=1/2) complexes. The crystal structures of 1.CH(3)OH and 2.CH(2)Cl(2) revealed that in these complexes the ligand coordinates in a hexadentate mode, affording examples of distorted octahedral M(II)N(2)(pyrazine)N'(2)(amide)S(2)(thioether) coordination. Each complex exhibits in CH(2)Cl(2) a reversible to quasireversible cyclic voltammetric response, corresponding to the Ni(III)/Ni(II)(1) and Cu(II)/Cu(I)(2) redox process. The E(1/2) values reveal that the complexes of bpzctb(2-) are uniformly more anodic by approximately 0.2 V than those of the corresponding complexes with the analogous pyridine ligand, 1,4-bis[o-(pyridine-2-carboxamidophenyl)]-1,4-dithiobutane (H(2)bpctb), attesting that compared to pyridine, pyrazine is a better stabilizer of the Ni(ii) or Cu(i) state. Coulometric oxidation of the previously reported complex [Ni(II)(bpctb)] and 1 generates [Ni(III)(bpctb)](+) and [Ni(III)(bpzctb)](+) species, which exhibit a LMCT transition in the 470--480 nm region and axial EPR spectra corresponding to a tetragonally elongated octahedral geometry. Complex 2 exhibits EPR spectra characteristic of the d(z(2)) ground state.     

The Reaction and Applied Study of the Amide and P_2S_5

It is usually reported that reaction between carbonyl and P2S5 produce thiono group compound. The Products from carbonyl after ammonolysis and hydrazinolysis have the very import applied value in the synthesize of heterocyclic compound. Sulfuration reation if a nucleophilic attack, SPS2 anionsid obtained from P2S5 in the organic sovent, rather easier than thereationsof scheeren’s reagent. The reation mechanism is as follows: The reation speed has something todo with the electronegative of…     

Thermodynamics of pyridine coordination in 1,4-phenylene bridged bimetallic (Pd, Pt) complexes containing two N,C,N' motifs, 1,4-M2-[C6(CH2NR2)4-2,3,5,6

The thermodynamics of pyridine coordination in 1,4-phenylene-bridged binuclear palladium and platinum organometallic complexes [1,4-(MOTf)2-&{C6(CH2NR2)4-2,3,5,6}] (11, M =Pd, Pt; R =CH3, C2H5, R2 = -(CH2)5-) are measured by 1H NMR in DMSO-d6. The coordination of substituted pyridines by bimetallic complexes 11 or 12 in DMSO is found to proceed via two effectively independent metalligand binding events, and the association constants for pyridine coordination and rate constants for pyridine exchange are nearly identical to those measured previously on monometallic analogs. A linear free energy relationship between the association constant for pyridine coordination and the inductive Hammett constant of the pyridine substituent is observed, and the sensitivity (rho = -1.7 to -2.1) in DMSO depends only slightly on metal (Pd vs Pt) and spectator ligand (pincer dialkylamine vs triarylphosphine). The association constant for a particular pyridine ligand, however, varies by roughly 3 orders of magnitude across the series of metal complexes. The effective independence of the two coordination sites and the range of available thermodynamic and kinetic behaviors of the coordination guide the use of these versatile building blocks in metallosupramolecular applications.