Pyridine In Ethanol Research Articles

Synthesis, crystal structure and thermal properties of poly[bis-[μ-3-(amino-meth-yl)pyridine-κ2 N:N']bis(thio-cyanato-κN)manganese(II)

The reaction of Mn(NCS)2 with a stoichiometric amount of 3-(amino-meth-yl)pyridine in ethanol led to the formation of the title compound, [Mn(NCS)2(C6H8N2)2] n , which is isotypic to its Zn, Co and Cd analogues. The manganese cation is located on a centre of inversion and is octa-hedrally coordinated in an all-trans configuration by two terminal N-bonded thio-cyanate anions as well as four 3-(amino-meth-yl)pyridine co-ligands, of which two coordinate with the pyridine N atom and two with the amino N atom. The 3-(amino-meth-yl)pyridine co-ligands connect the MnII cations into layers extending parallel to (10). These layers are further connected into a three-dimensional network by relatively strong inter-molecular N-H⋯S hydrogen bonding. Comparison of the experimental X-ray powder diffraction pattern with the calculated pattern on the basis of single-crystal data proves the formation of a pure crystalline phase. IR measurements showed the CN stretching vibration of the thio-cyanate anions at 2067 cm-1, which is in agreement with the presence of terminally N-bonded anionic ligands. TG-DTA measurements revealed that the title compound decomposes at about 500 K.

A Study of the Crystal Structure and Hydrogen Bonding of 3-Trifluoroacetyloxime Substituted 7-Acetamido-2-aryl-5-bromoindoles

The 7-acetyl-2-aryl-5-bromo-3-(trifluoroacetyl)indoles 1a-d were reacted with hydroxylamine hydrochloride (2.2 equiv.) in the presence of pyridine in ethanol under reflux to afford the corresponding diketo oxime derivatives 2a-d. Beckmann rearrangement of the latter with trifluoroacetic acid under reflux afforded the corresponding 7-acetamido-2-aryl-5-bromo-3-(trifluoroacetyloxime)indoles 3a-d. The structures of the prepared compounds were characterized using a combination of NMR (1H & 13C), IR, and mass spectrometric techniques. The molecular structure of the 3-trifluoroacetyloxime substituted 7-acetamido-2-aryl-5-bromoindoles was unambiguously confirmed by the single crystal X-ray diffraction data of 3d. Structural studies of 3d in the solid state by X-ray crystallography provided evidence of hydrogen bonding networks and π-stacking of the indole moiety. Compound 3d was crystallized in the trigonal space group R-3:H with unit cell dimensions a = 25.1614(13), b = 25.1614(13), c = 17.3032(9) Å, α = β = 90°, γ = 120°, V = 9486.9(11) Å3, Z = 6. The density functional theory (DFT) structural parameters (bond lengths, bond angles, and torsion angles) of the optimized geometry calculated using the B3LYP/6-311G basis set were found to compare favourably with those of the X-ray crystal structure.

Further calculations on solubility of 2-chloro-3-(trifluoromethyl)pyridine in ethanol + 1-propanol solvent mixtures at various temperatures

The reported calculations on solubility data of 2-chloro-3-(trifluoromethyl)pyridine in binary ethanol+1-propanol solvent mixtures at various temperatures have been reanalyzed and several additional points regarding the correlations were reported. In addition preferential solvation of 2-chloro-3-(trifluoromethyl)pyridine in ethanol+1-propanol mixtures were investigated by means of the inverse Kirkwood-Buff integrals method. Apparently no preferential solvation of this compound by both organic solvents is observed because the respective parameters are lower than 0.01 in all the analyzed compositions.

Synthesis of furo[3,2-c]coumarins under microwave irradiation using nano-CoFe2O4@SiO2–PrNH2 as an efficient and magnetically reusable catalyst

CoFe2O4@SiO2–PrNH2 nanoparticles have been used as an efficient and magnetically recoverable catalyst for the preparation of trans-3-aryl-2-(4-bromobenzoyl)-2,3-dihydro-4H-furo[3,2-c]chromen-4-ones by multicomponent reaction of 2,4'-dibromoacetophenone, aromatic aldehydes, and 4-hydroxycoumarin in the presence of pyridine in ethanol under microwave irradiation. It was demonstrated by 1H NMR spectroscopy and single crystal analysis that the obtained furo[3,2-c]coumarins were the trans-isomers.

Redox Properties and Catalytic Ability toward Electrochemical Proton Reduction of Sulfur-Bridged Trinuclear Mo3S4 Complexes Containing Acetate, Trifluoroacetate, and/or Dithiophosphate as Bridging Ligands

Abstract A novel complex with the terminal acetonitrile and bridging trifluoroacetate (tfa) ligands of [Mo3S4(dtp)3(μ-tfa)(NCCH3)] (dtp: diethyl dithiophospate) (1-tfa) was prepared from the substitution reaction of [Mo3S4(dtp)3(μ-dtp)(NCCH3)] (1-dtp) with trifluoroacetate anhydride in acetonitrile. The reaction of 1-dtp with trifluoroacetic acid in dichloromethane also afforded 1-tfa. Complex 1-tfa reacts with pyridine in ethanol resulting in the formation of a complex with the terminal pyridine ligand (py), [Mo3S4(dtp)3(μ-tfa)(py)] (2-tfa). Structures of 1-tfa and 2-tfa were determined by single-crystal X-ray structural analysis showing that one of three Mo–Mo distances depend on a kind of the bridging ligands, dtp, OAc, and tfa, while no trends in the other two Mo–Mo distances in each of the complexes with the different bridging ligands. Each of the cyclic voltammograms of 1-dtp, [Mo3S4(dtp)3(μ-OAc)(NCCH3)] (OAc: acetate) (1-OAc), 1-tfa, [Mo3S4(dtp)3(μ-OAc)(py)] (2-OAc), and 2-tfa showed two consecutive one-electron reduction waves and an oxidation wave, which are formally assigned to the Mo(IV IV IV)/Mo(III IV IV), Mo(III IV IV)/Mo(III III IV), and Mo(V IV IV)/Mo(IV IV IV) couples, respectively. The re-oxidation and re-reduction peaks for the second reduction and the oxidation processes were not observed for all of the complexes. The redox potentials of the first reduction processes were shifted up to ca. 200 mV with the bridging and terminal ligands, for example, the redox potentials appeared at −0.98 and −1.19 V vs. Fc/Fc+2-OAc and 1-tfa, respectively, due to the lower electron-donating ability of CH3CN and tfa ligands compared to that of the py and OAc ligands. The re-oxidation peak for the second reduction process of 2-OAc was observed at −80 °C suggesting that this is an EC process and the chemical reaction following the second electrochemical reduction is probably inhibited at low temperature. On the other hand, no re-reduction peak for the oxidation process appeared even at −80 °C implying that the oxidation process is accompanied by a significant structural change. This argument is supported by the results of the DFT calculation. The HOMO component of the complex contains a bonding character between the two acetate-bridged Mo centers and the other acetate-unbridged one, and the spin densities of the 1-electron oxidized complex mostly located at the one of two acetate-bridged Mo centers and the other acetate-unbridged one. Cyclic voltammograms of these complexes in the presence of trifluoroacetic acid as a proton source exhibited catalytic currents around the first reduction wave for each complex. The DFT calculations for 2-OAc and 2-tfa demonstrated that the HOMO components are also distributed over the doubly bridged sulfur ligands in addition to the Mo centers in the Mo3S4 core. These result suggests that a protonation reaction of 2-OAc and 2-tfa probably occurs on the doubly bridged sulfur ligand in the Mo3S4 core.

Preparation and characterization of cyclopalladated complexes derived from l-(−)-fenchone

l-(−)-Fenchone 4 was reacted with RONH2·HCl (R = H or Me) and pyridine in ethanol to give l-fenchone oxime 5a and the corresponding O-methyl derivative 5b in 64 and 82% yields, respectively. Reactions of oximes 5a,b with Pd(OAc)2 in acetic acid at 80 °C followed by treatment with LiCl provided dimeric cyclopalladated complexes 7a,b in 65 and 49% yields. Compounds 7a,b were then converted to the mononuclear PPh3 derivatives 8a,b in 99 and 78% yields. The proposed structures of the synthesized complexes were supported by 1H, 13C{1H}, DEPT and 2D NMR spectra. Molecular structures of complexes 8a,b confirmed their trans-N,P geometry and the presence of the (sp3)C–Pd bond.

Synthesis of 3-Aminopyridin-2(1H)-Ones and 1H-Pyrido[2,3-b][1,4]Oxazin-2(3H)-Ones

The interaction of 1,3-diketones with chloroacetamide produced N-(3-oxoalkenyl)chloroacetamides. Heating of N-(3-oxoalkenyl)chloroacetamides with an excess of pyridine in ethanol or butanol led to the formation of pyridin-2(1Н)-ones, substituted with a pyridine ring at position 3. The reactions of these compounds with hydrazine hydrate produced 3-aminopyridin-2(1Н)-ones. The synthesis of 1H-pyrido[2,3-b][1, 4]oxazin-2(3H)-ones was accomplished by a reaction of 3-aminopyridin-2(1Н)-ones with chloroacetyl chloride.

Metamagnetism and Single‐Chain Magnetic Behavior in a Homospin One‐Dimensional Iron(II) Coordination Polymer

Reaction of FeCl(2)·4H(2)O with KNCSe and pyridine in ethanol leads to the formation of the discrete complex [Fe(NCSe)(2)(pyridine)(4)] (1) in which the Fe(II) cations are coordinated by two N-terminal-bonded selenocyanato anions and four pyridine co-ligands. Thermal treatment of compound 1 enforces the removal of half of the co-ligands leading to the formation of a ligand-deficient (lacking on neutral co-ligands) intermediate of composition [Fe(NCSe)(2)(pyridine)(2)](n) (2) to which we have found no access in the liquid phase. Compound 2 is obtained only as a microcrystalline powder, but it is isotypic to [Cd(NCSe)(2)(pyridine)(2)](n) and therefore, its structure was determined by Rietveld refinement. In its crystal structure the metal cations are coordinated by two pyridine ligands and four selenocyanato anions and are linked into chains by μ-1,3 bridging anionic ligands. Magnetic measurements on compound 1 show only paramagnetic behavior, whereas for compound 2 an unexpected magnetic behavior is found, which to the best of our knowledge was never observed before for a iron(II) homospin compound. In this compound metamagnetism and single-chain magnetic behavior coexist. The metamagnetic transition between the antiferromagnetically ordered phase and a field-induced ferromagnetic phase of the high-spin iron(II) spin carriers is observed at a transition field H(C) of 1300 Oe and the single-chain magnetic behavior is characterized by a blocking temperature T(B), estimated to be about 5 K.

Physical properties of a new iron(III) complex, [3-pmH · 3-pm][Fe(NCS)4(3-pm)2

The iron(III) compound of formula [3-pmH · 3-pm][Fe(NCS)4(3-pm)2] (3-pm = 3-(hydroxymethyl)pyridine) has been prepared by reaction between iron(III) thiocyanate and 3-(hydroxymethyl)pyridine in ethanol. The characterization was based on elemental analysis, infrared spectra and magnetic measurements. Single crystal X-ray diffraction methods show the monoclinic P2(1)/c space group with unit cell parameters: a = 12.295(3) Å, b = 15.854(3) Å, c = 16.880(3) Å, β = 100.12(3)° and Z = 4. The asymmetric unit of the title compound consists of [3-pmH · 3-pm]+ and [Fe(NCS)4(3-pm)2]− held together by ionic interaction and a hydrogen bond interaction (O(68)–H(68) ··· O(78)). The central metal ion is octahedrally coordinated by six nitrogens, four from NCS− form the equatorial plane and two from two 3-(hydroxymethyl)pyridines occupy axial positions. Magnetic susceptibility data in the temperature range 1.8–300 K show that iron(III) is high-spin S = 5/2(5 T 2g). Structural parameters and IR spectra of similar complexes are compared and discussed.

Synthesis and Reactions of 2‐ and 4‐Substituted Furo[3,2‐c]pyridines.

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Synthesis and reactions of 2-and 4-substituted furo[3,2-c]pyridines

AbstractSubstituted furopropenoic acids were prepared from appropriate aldehyde under the Doebner’s conditions. Obtained acids were converted to the corresponding azides, which were cyclized by heating in Dowtherm to furopyridones. These compounds were aromatized with phosphorus oxychloride to chloro derivatives of furo[3,2-c]pyridine (Va, Vb). Chloro derivative Vb was reduced with hydrazine hydrate to 2-(4-aminophenyl)furo[3,2-c]pyridine in ethanol and Pd/C as a catalyst. Chloro derivative Va was converted to 4-amino-2-(3-pyridyl)furo[3,2-c]pyridine under the same conditions. The chlorine atom in other chloro derivatives (VIIa, VIIb) was replaced by nucleophilic substitution with alkoxides (sodium ethoxide, propoxide, and isopropoxide) and the corresponding alkoxy derivatives were formed. By reaction of VII with cyclic secondary amines (morpholine, piperidine, and pyrrolidine) 4-substituted furopyridines were prepared.

Some 4-Substituted 1-(3-Pyridylmethyl)piperazines with Antihistamine Activity

Several compounds derived from nicotinic acid were prepared within a more extensive programme aiming at the synthesis of new substances with expected antihistamine and antidepressant activity. Some of these compounds display certain structural resemblance with the antidepressant agent piberaline (EGYT 475, Trelibet®, I) and its analogues. The products were used as intermediates for the synthesis of further compounds and most of them were subjected to pharmacological testing. Substituted nicotinic acid piperazides IIa - IId and IVa - IVe were obtained by reactions of nicotinoyl chloride (prepared in situ) with the correspondingly substituted piperazines. Reduction of the piperazides IIa - IId and IVa - IVd with diborane in situ in tetrahydrofuran afforded corresponding 1-substituted 4-(3-pyridylmethyl)piperazines IIIa - IIId and Va - Vd. Whereas the alkylation of 1-(2-pyrimidinyl)piperazine with 2-(chloromethyl)pyridine in ethanol in the presence of triethylamine resulted in compounds Ve, compound Vf was obtained by the addition reaction of 1-(3-pyridylmethyl)piperazine to acrylamide. The piperazides VIe and VIf were prepared by reactions of 2-(3-pyridyl)acetic acid with 1-(2-pyrimidinyl)piperazine or 3-(1-piperazinyl)propionamide in N,N-dimethylformamide in the presence 1,1'-carbonyldiimidazole. A similar procedure starting from nicotinic acid afforded the piperazide IVf. Compounds Vc and Vd showed significant affinity for the histamine H1-receptors (inhibition of binding of 2 nmol/l [3H]mepyramine in membranes from the rat brain: Vc, IC50 = 28 nmol/l; Vd, IC50 = 148 nmol/l). They also proved active in test of histamine aerosol in guinea pigs (PD50 = 4.1 mg/kg p.o. for compound Vc and 2.4 for compound Vd). Results of a more detailed pharmacological testing of these compounds will be published elsewhere.

The Structure and Solid State Reactivity of a Cocrystal of Propynoic Acid and 4-(1 -pyrrolidino)-pyridine. A Study of γ-Ray-Induced vs. Thermal Reactivity

Abstract Mixing propynoic acid and 4-(l-pyrrolidino)-pyridine in ethanol produces the salt 4-(l-pyrrolidino)-pyridinium propynoate (1) in high yield. An X-ray structure determination of 1 (Space Group P2I , Z=4) shows it to contain two independent cation-anion sets. Each set is interconnected by N-H-0 and C-H-O hydrogen bonds; there are no hydrogen bonds formed between the two sets. Each set contains an infinite array of short acetylene-acetylene contacts (3.57 and 3.74 A, respectively); despite this characteristic, the material does not polymerize upon exposure to 60Co γ-rays. Heating 1 at 125 °C for 23 hours converts it, in high yield, to a 19:1 mixture of (E and Z)-4-(l-pyrrolidino)-pyridinium-l-acrylate. To the best of our knowledge, this is the first example of the addition of a pyridine moiety to an acetylene in the solid state.

Study of the state of aluminium in zeolite-β

The modifications of the state of aluminium when introducing protons into zeolite-β have been investigated by combining several analytical techniques. Low temperature (350°C) thermolysis of ammonium cations or treatment with dilute nitric acid provokes the development of a 27Al NMR signal at 0 ppm attributable to aluminium in octahedral symmetry. Calcination at 550°C generates NMR invisible aluminium and a strongly acidic hydroxyl group vibrating at 3780 cm −1 in the infra-red spectra. The neutralization of the protons by reaction with a solution of pyridine in ethanol at room temperature or with gaseous ammonia at 100°C allows for all the aluminium atoms of the solid to recover a tetrahedral symmetry. The Al IV → Al VI transformation can be also reversed by replacing the protons by sodium or potassium cations. It is then concluded that the octahedrally coordinated and NMR invisible aluminium must be regarded as inherent parts of the framework of the zeolite. Their formation is explained by a distortion of aluminic sites caused by the high electron affinity of the proton.

Preparation and reactions of trihalogeno(pentamethylcyclopentadienyl)ruthenium(IV)

The reaction of [(C 5Me 5)RuCl 2] m with halogen (Cl 2, Br 2, and I 2) in dichloromethane gives trihalogenoruthenium(IV) complexes, [(C 5Me 5)RuX 3] n (X = Cl, Br, and I), ( 2) in excellent yields. The Ru IV complexes formulated as (C 5Me 5)RuX 3(L) ( 3) are formed in the reaction of complex 2 with triphenylphosphine or carbon monoxide in dichloromethane, while treatment of complex 2 with triphenylphosphine or pyridine in ethanol exclusively affords Ru III complexes, (C 5Me 5)RuX 2(L) ( 4).

Strukturisomere von Kupfer(I)iodid · Pyridin und ihre Lumineszenzeigenschaften. Darstellung und Kristallstruktur einer neuen Modifikation von Cul · NC5H5 / Structural Isomers of Copper(I) Iodide Pyridine and their Luminescence Properties Synthesis and Crystal Structure of a New Modification of Cul · NC5H5

Abstract A new modification of CuI · py was prepared by the reaction of a saturated solution of CuI in CH3CN with a solution of pyridine in ethanol at 60 °C. It crystallizes monoclinic with four formula units in the space group P21/c. (CuI · py)∞ forms a polymeric ribbon structure. Contrary to the cubane-like tetrameric modification, (CuI · py)∞ does not show luminescence thermochromism. The luminescence properties of both modifications of Cul · py are interpreted.

The Reaction of Ethyl Ethoxymethylenecyanoacetate with Its Hydrazino Derivatives

Abstract The reaction of ethyl ethoxymethylenecyanoacetate with its hydrazino derivative in the presence of pyridine in ethanol at room temperature gave ethyl (4-ethoxycarbonyl-5-aminopyrazol-1-yl)methylenecyanoacetate(6) and two geometric isomers of ethyl (4-ethoxycarbonylpyrazol-5-ylamino)methylenecyanoacetate(7). Compound 6 itself, under the same conditions, rearranged to compound 7. Both compounds, 6 and 7, upon heating cyclized exclusively to the same product, diethyl 7-aminopyrazolo[1,5-a]pyrimidine-3,6-dicarboxylate(8). From the results of other combination reactions on methylenecyanoacetic ester homologs, a plausible reaction mechanism involving a rearrangement is discussed.

Behaviour of nitrile oxides towards nucleophiles. Part I. Pyridine-catalysed dimerisation of aromatic nitrile oxides

When treated with pyridine in ethanol, non-hindered aromatic nitrile oxides dimerise to 3,6-diaryl-1,4,2,5-dioxadiazines, whose structures have been proved by the results of catalytic hydrogenation. The dimerisation of 2,4-dichlorobenzonitrile oxide has been shown to be second-order in the nitrile oxide and first-order in the nucleophile. A reaction scheme is suggested in which an intermediate adduct between nitrile oxide and pyridine reacts with more nitrile oxide to give the dimer.

Ultraviolet emission and absorption spectra produced by organic compounds in oxyhydrogen flames 1: Emission spectra

Ultraviolet emission spectra produced by aspirating organic compounds into oxyhydrogen flames have been investigated. Spectra are presented and compared. The prominent bands observed are listed by wavelength and species emitting. Flame emission profiles for organic and inorganic fragments are presented. Maximum emission by organic fragments occurred in the reaction zone of the flame. Emission by OH and fragments containing phosphorus or sulfur was intense above and within the reaction zone of the flame. Spectra obtained by varying the hydrogen-to-oxygen ratio in the flame and by aspirating with hydrogen instead of oxygen reflected the different sizes of the resulting flames. The bands observed were similar. Estimates of detection limits obtained for pyridine and ethanol by measuring the intensities of emission from NH and CH fragments were ⩾2% pyridine in ethanol and ⩾5% ethanol in water.