Synthesis of nitrogen containing heterocycles over copper chromite

The reactions of 1,2-diaminopropane, 1-amino-2-propanol, 1-amino-2-ethanol and N-(-aminoethyl)-1,2-diaminoethane in the gas phase over copper chromite have been investigated with the objective of synthesising nitrogen containing heterocycles. At 240–360°C 1,2-diaminopropane gave principally methyl- and 2,5-dimethylpyrazine, whereas the basic reaction for 1-amino-2-propanol was dehydration to give 1-aminoethyl-2-methylaziridine (with a selectivity of up to 78%). The main cyclic product from the dehydration of 1-amino-2-ethanol was pyrazine, while piperazine was farmed together with pyrazine from N-(-amonoethyl)-1-2-diaminoethane.Latvian Institute of Organic Synthesis, Riga, LV-1006. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 950–957, July, 1994.     

Enthalpies of proton transfer of hydroxy amines and maltol in methanol-water mixtures by direct calorimetry

Enthalpies of proton transfer in methanol-water mixtures (0–90 wt. % methanol) have been measured by direct calorimetry for the bases 2-amino-2-methyl-1-propanol, 2-amino-2-methyl-1,3-propanediol and 2,2-bis(hydroxymethyl)-2,2,2-nitrilotriethanol at 25°C. Also reported are the data for 3-hydroxy-2-methyl-4-pyrone. The results are discussed in terms of an adaptation of classical electrostatic formula.     

Volumetric properties of dilute aqueous solutions of cobalt amine type salts. Part 2. Densities at 15 and 5°C

Apparent molar volumes have been determined by density measurements of aqueous solutions for a series of salts [Co(L)₃]X₃, where X=Cl^– and Br^– and L¹=1,2-diaminoethane (en), L²=1,2-diaminopropane (pn) and L³=1,3-diaminopropane (tn) at 15°C and 5°C. Apparent molar volumes at infinite dilution for the complex cations at 0°C are estimated. The resulting values are related to the structure of solvent water molecules around the ions.     

Osmotic coefficients of dilute aqueous solutions of unsymmetrical cobalt-amine type salts at 0°C

The osmotic coefficients of dilute aqueous solutions of [Co(pn)₃]X₃ [pn=1,2-diaminopropane and X=Cl^–, Br^– and (NO₃)^–] and [Co(tn)₃]X₃ (tn=1,3-diaminopropane and X=Cl^– and Br^–) have been measured from 0.00 to 0.02 mol-kg^–1 at 0°C by the freezing point method. The results have been compared with those obtained from the numerical integration of the Poisson-Boltzmann equation.     

Cu-superconductors in organic catalysis I. Isomerization and hydrogenation of allyl alcohol on YBa2Cu3O7?x

On the superconductor YBa₂Cu₃O_7–x between 150 and 300°C, allyl alcohol is isomerized to propionaldehyde (70%) and hydrogenated to 1-propanol (30%) in hydrogen.     

Volumetric properties of dilute aqueous solutions of cobalt-amine-type salts. Part I. Densities at 25°C

The densities of dilute aqueous solutions of [CoL₃]X₃ [L=1,2-diaminoethane(en), 1,2-diaminopropane(pn), 1,3-diaminopropane(tn) X=Cl^–, Br^– and (ClO₄)^–] have been measured at 25°C from 0 to 5×10^–2m. The apparent molar volumes were calculated and extrapolated to infinite dilution. Ion-solvent interactions were detected from the change of the ionic partial molar volumes with concentration. These interactions depend both on the properties of the ion (polarization charge density at the surface, hydrophobic groups, etc.) and the characteristics and structure of the solvent.     

The Relationship between the State of Active Species in a Ni/Al2O3Catalyst and the Mechanism of Growth of Filamentous Carbon

The formation of active particles and their changes in the course of 1,3-butadiene decomposition on a Ni/Al₂O₃catalyst at temperatures from 400 to 800°C were studied by high-resolution electron microscopy. It was found that carbon filaments of different types were formed at 400–800°C. The growth of thin filaments (20–30 nm in diameter) takes place at 400–600°C on a conical Ni particle located at the growing end of the filament, whereas di-symmetrical filaments 50–100 nm in diameter grow on biconical metal particles. As the carbonization temperature was increased to 700–800°C, graphite nanotubes 5–20 nm in diameter were formed. It was found that the mechanism of formation and the structure of filaments are related to the state of catalytically active species, which consist of a solid solution of carbon in the metal. It is suggested that the metastable surface nickel carbide Ni₃C_{1 – x} is an intermediate compound in the catalytic formation of graphite filaments from 1,3-butadiene. Upon termination of the reaction, the metastable Ni₃C_{1 – x} microphase is decomposed with the formation of hexagonal nickel microinclusions. The role of epitaxy in the nucleation and growth of a graphite phase on the metal is discussed. Models are presented for the growth of structurally different carbon filaments depending on the formation of active metal species at various temperatures. Considerable changes in the structure of carbon and the formation of nanotubes at 700–800°C are related to the appearance of a viscous-flow state of metal–carbon particles.     

Synthesis of 4,6-bis(1H-1,2,3-triazolyl)pyrimidines by the reaction of 4,6-diazido-2-(4-methoxyphenyl)-pyrimidine with compounds containing a reactive methylene group

The reaction of 4,6-diazido-2-(4-methoxyphenyl)pyrimidine with cyanoacetic ester in the presence of triethylamine leads only to 4-azido-6-amino-1-(4-methoxyphenyl)pyrimidine. The main product in reactions with 1,3-dicarbonyl compounds (acetylacetone, acetoacetic and benzoylacetic esters) is the corresponding substituted 4,6-bis(1H-1,2,3-triazolyl)pyrimidine. The formation of 4-azido-6-(1H-1,2,3-triazolyl)pyrimidine and 4-amino-6-(1H-1,2,3-triazolyl)pyrimidine as minor products was also recorded.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1109–1114, August, 1997.     

Homolytic replacement of a hydrogen atom in 2-methylquinoline by A 1,3-dioxolanyl residue

The reaction of 1,3-dioxolane with sulfuric-acid-protonated 2-methylquinoline initiated by the ROOH + Fe²⁺ system [where R = H, (CH₃)₃C, or C₆H₅C(CH₃)₂] at 5–10 °C in water forms 4-(1,3-dioxacyclopent-2-yl)-2-methylquinoline and 4-(1,3-dioxacy-clopent-4-yl)-2-methylquinoline. The selectivity of the formation of the first reaction product increases on passing from hydrogen peroxide to cumyl and tert-butyl hydroperoxide and with an increase in the pH of the medium.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 25–28, January, 1984.     

Cyclocondensation of α,Β-unsaturated ketones with 3-amino-1,2,4-triazole

Dihydro-1,2,4-triazolo[1,5-a]pyrimidine derivatives were obtained by condensation of 3-amino-1,2,4-triazole with 1,3-diaryl-1-propen-3-ones. The structure of 5-phenyl-7-(4-methylphenyl)-4,7-dihydro-1,2,4-triazolo[1,5-a]pyrimidine was established by x-ray diffraction analysis.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 229–233, February, 1988.     

Protonation and silver(I) complex-formation equilibria of some amino-alcohols

Formation constants of the silver(I) complexes with some amino-alcohols have been determined at 25 degrees C in 0.5 M KNO(3) by means of two independent potentiometric measurements employing glass and silver electrode. The ligands considered are: sec-butylamine, 2-amino-1-propanol, 2-amino-1-methoxy-propane, 2-amino-2-methyl-1-propanol, 2-amino-1-butanol, 2-amino-1-pentanol, 2-amino-1-hexanol, 2-amino-1,3-propanediol, 2-amino-1,3-hexandiol, 2-amino-2-methyl-1,3-propanediol and Tris(hydroxymethyl)-aminomethane. Protonation constants of the selected ligands have also been determined. Calculations were made using HYPERQUAD computer program. The influence exerted by the introduction of hydroxy groups and by the presence of alkyl residuals in the ligand structure on the formation equilibria, is discussed.     

A rapid and sensitive GC–MS method for determination of 1,3-dichloro-2-propanol in water

A rapid analytical method for sensitive determination of 1,3-dichloro-2-propanol (1,3-DCP) in river water has been developed. 1,3-DCP is extracted from water with ethyl acetate. After filtration through sodium sulfate the ethyl acetate phase is analyzed by gas chromatography–mass spectrometry. The method uses 1,3-DCP-d₅ as internal standard. Different extraction solvents, concentrations of ammonium sulfate in the water samples, and the effect of humic acid were tested and their influence on the recovery of DCP has been evaluated. The method quantification limit was 0.1 g L^–1. For spiked water samples (0–5.2 g L^–1, n=21) a repeatability coefficient of variation of 5.4% was obtained. The average recovery rate of 1,3-DCP was 105±3% (n=21). Stability tests, which were carried out with Danube river water, led to an estimated 1,3-DCP degradation rate of 0.008±0.0008 day^–1 at 6°C.     

Pyrido[2,3-d]pyrimidines. 2. Reactions of 2,4,5-trioxo-7-amino-8H-pyrido[2,3-d]pyrimidines with electrophilic agents

1,3-Dimethyl-2,4,5-trioxo-7-amino-8H-pyrido[2,3-d]pyrimidine has been brominated, chlorosulfonated, treated with potassium nitrite in acidic medium, and with the Vilsmeier reagent. Acylation and alkylation of 1,3-dimethyl-2,4,5-trioxo-6-bromo-7-aminopyrido[2,3-d]pyrimidine is also discussed.For Communication 1, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 662–666, May, 1990.     

Reaction of esters of 2-substituted 5-pyrimidinecarboxylic acids with hydrazine hydrate

The reaction of methyl esters of 2-substituted 5-pyrimidinecarboxylic acids with hydrazine hydrate at 0–5°C results in the nucleophilic substitution of readily eliminating groups (Cl, CH₃O, CH₃S) at the position 2 of the pyrimidine ring, and, on the boiling with the 80% aqueous solution of hydrazine hydrate, the reaction is accompanied by the formation of hydrazides. The dimethylamino group at thepposition 2 of the pyrimidine ring is not substituted by hydrazine.Vilnius University, Vilnius 2006, Lithuania Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1528–1530, November, 1999.     

Formation of Carbon Filaments from 1,3-Butadiene on Fe/Al2O3 Catalysts

The formation of carbon filaments with different crystallographic and morphological characteristics in the course of 1,3-butadiene decomposition on Fe/Al₂O₃ catalysts at low (500–600°C) and high (700–800°C) temperatures was considered in terms of a carbide cycle mechanism. The conditions of formation and decomposition of an iron carbide phase in the course of formation of graphite nanotubes in the low-temperature region were studied.     

Synthesis and characterization of NiSn colloids and active solids prepared in organic solvents by CLD

Bimetallic colloidal dispersions were obtained by simultaneous cocondensation of nickel and tin atoms with organic solvents at 77 K using the chemical liquid deposition (CLD) method. The atoms in a 1:1 ratio were produced by resistive heating and were reacted with 2-propanol, 2-methoxyethanol, and acetone to produce colloids.The kinetic stability of the colloid dispersions was related to the solvation effect of organic molecules, e.g., low stability for acetone, higher for 2-propanol, and the highest for 2-methoxyethanol. The colloidal particles were characterized by UV-Vis measurements showing absorption bands at 204 and 270 nm. A 3-day study in which samples were taken every hour showed that the absorption bands decrease probably due to clustering. Electrophoretic measurements revealed that the particles are weakly positively charged. Transmission electron microscopy studies revealed an average particle size distribution ranging from 6 to 10 nm depending on the solvent. Most of the colloids exhibit a spherical shape with some degree of agglomeration.After solvent evaporation several active solids were obtained. The FTIR spectra show the presence of the solvent incorporated in the active solids/films, e.g., for acetone the carbonyl stretching is observed at 1723 cm^–1. The thermal stability of these bimetal powders/films was studied by TGA up to 550 °C. Their maximum decomposition temperatures are 350, 415, and 429 °C for NiSn–2-methoxyethanol, –2-propanol, and –acetone, respectively.     

Preparation and performance characterization of polymer Li-ion batteries using gel poly(diacrylate) electrolyte prepared by in situ thermal polymerization

A gel polymer electrolyte (GPE) was prepared by in-situ thermal polymerization of 1,3-butanediol diacrylate (BDDA) in a EC/EMC/DMC electrolyte solution at 100 °C. The GPE with 15 wt.% polymer content appears as apparently dry polymer with sufficient mechanical strength and shows a high ionic conductivity of 3.2×10^–3 S cm^–1 at 20 °C. The MCMB–LiCoO₂ type polymer Li-ion batteries (PLIB) prepared using this in-situ internal polymerization method exhibit a very high initial charge–discharge efficiency of 92.1%, and can deliver 94.4% of its nominal capacity at 1.0 C rate and 70.7% of its room temperature capacity at –20 °C. Also, the PLIB cells show very good cycling ability with >85% capacity retention after 300 cycles. The excellent charge–discharge properties of the PLIB cells are attributed to the integrated structure in which the polymer matrix spreads over entire region of the cell acting as a strong binder and electrolyte carrier to produce a stabilized electrode–electrolyte interface. In addition, the fabricating process of the polymer cell is quite simple and convenient for practical applications.     

Heterogeneous catalysts in the alkylation of imidazoles

The reaction of imidazoles with alcohols at 300–400°C was studied in the presence of heterogeneous -Al₂O₃ catalysts and Y zeolites. The major reaction was found to be N-alkylation. This reaction is accompanied by C-alkylation on -Al₂O₃ while the selectivity relative to N-alkylation is close to 100% on zeolite catalysts. The greatest activity with 100% selectivity was found for H zeolite. The alkylation of methanol and ethanol by 2-methylimidazole at 310–320°C gave 1,2-dimethylimidazole in -100% yield and 1-ethyl-2-methylimidazole in 90% yield respectively. The reaction of methanol and imidazole gave 1-methylimidazole in 99% yield. This catalyst displays high stability and capacity for oxidative regeneration.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 624–628, May, 1994. Original article submitted April 20, 1994.     

Structure of 2-amino-5-methylthiazoline and its N-methyl derivatives

As indicated by PMR spectroscopic data, 2-amino-5-methylthiazoline and 2-methylamino-5-methylthiazoline exist in the imine form in the temperature interval from +20° to –100° C. Interaction of the 2-amino-5-methylthiazoline with methyl iodide results in alkylation at the endocyclic nitrogen atom.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 415–419, March, 1993.     

Deamination of amines of adamantane series

Conclusions The deamination of 1-aminoadamantane, 1,3-diammoadamantane and 1-amino-3-adamantanol leads to the formation of the corresponding alcohols. The isomerization of the adamantane skeleton was not observed in all cases.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimlcheskaya, No. 10, pp. 2378–2379, October, 1973.