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Azines

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Rosa M Claramunt – 1st expert on this subject based on the ideXlab platform

  • the structure of Azines derived from c formyl 1h imidazoles in solution and in the solid state tautomerism configurational and conformational studies
    Magnetic Resonance in Chemistry, 2013
    Co-Authors: Joana Pinto, Vera L M Silva, Artur M S Silva, Rosa M Claramunt, Dionisia Sanz, Carmen M Torralba, Rosario M Torres, Felipe Reviriego, Ibon Alkorta, Jose Elguero

    Abstract:

    The structures of three Azines derived from 2-formylimidazole, 4(5)-formylimidazole, and 4(5)-formyl-5(4)-methylimidazole have been determined in solution and in the solid state. Density Functional Theory (DFT) Polarizable Continuum Model (PCM) calculations (geometries, energies, and chemical shifts), NMR [solution and cross polarization magic-angle spinning (CPMAS)], and X-ray crystallography [azine of 4(5)-formylimidazole] have been used. The configuration around the central C = N bonds has been determined and some insights about prototropic tautomerism and conformation have been gained. Copyright © 2013 John Wiley & Sons, Ltd.

  • the azido tetrazole and diazo 1 2 3 triazole tautomerism in six membered heteroaromatic rings and their relationships with aromaticity Azines and perimidine
    Tetrahedron, 2010
    Co-Authors: Ibon Alkorta, Jose Elguero, Fernando Blanco, Rosa M Claramunt

    Abstract:

    Abstract The properties of 28 molecules together with 12 transition states belonging to the series of azido-Azines, tetrazolo-Azines, diazo-Azines, and 1,2,3-triazolo-Azines have been studied at the B3LYP/6-31G(d), B3LYP/6-311++G(d,p) and, for 26 cases, at the G3B3 level. Energies, NICS and bond critical points were used to discuss the ring-chain tautomerism of these compounds in relation with the aromaticity of the Azines (pyridine, pyrimidine, quinazoline, 1,3-diazapyrene, and perimidine) and the azoles (tetrazoles and 1,2,3-triazoles).

Christoforos G Kokotos – 2nd expert on this subject based on the ideXlab platform

  • 2 2 2 trifluoroacetophenone as an organocatalyst for the oxidation of tertiary amines and Azines to n oxides
    Chemistry: A European Journal, 2014
    Co-Authors: Dimitris Limnios, Christoforos G Kokotos

    Abstract:

    A cheap, mild and environmentally friendly oxidation of tertiary amines and Azines to the corresponding N-oxides is reported by using polyfluoroalkyl ketones as efficient organocatalysts. 2,2,2-Trifluoroacetophenone was identified as the optimum catalyst for the oxidation of aliphatic tertiary amines and Azines. This oxidation is chemoselective and proceeds in high-to-quantitative yields utilizing 10 mol % of the catalyst and H2O2 as the oxidant.

Ibon Alkorta – 3rd expert on this subject based on the ideXlab platform

  • the structure of Azines derived from c formyl 1h imidazoles in solution and in the solid state tautomerism configurational and conformational studies
    Magnetic Resonance in Chemistry, 2013
    Co-Authors: Joana Pinto, Vera L M Silva, Artur M S Silva, Rosa M Claramunt, Dionisia Sanz, Carmen M Torralba, Rosario M Torres, Felipe Reviriego, Ibon Alkorta, Jose Elguero

    Abstract:

    The structures of three Azines derived from 2-formylimidazole, 4(5)-formylimidazole, and 4(5)-formyl-5(4)-methylimidazole have been determined in solution and in the solid state. Density Functional Theory (DFT) Polarizable Continuum Model (PCM) calculations (geometries, energies, and chemical shifts), NMR [solution and cross polarization magic-angle spinning (CPMAS)], and X-ray crystallography [azine of 4(5)-formylimidazole] have been used. The configuration around the central C = N bonds has been determined and some insights about prototropic tautomerism and conformation have been gained. Copyright © 2013 John Wiley & Sons, Ltd.

  • the azido tetrazole and diazo 1 2 3 triazole tautomerism in six membered heteroaromatic rings and their relationships with aromaticity Azines and perimidine
    Tetrahedron, 2010
    Co-Authors: Ibon Alkorta, Jose Elguero, Fernando Blanco, Rosa M Claramunt

    Abstract:

    Abstract The properties of 28 molecules together with 12 transition states belonging to the series of azido-Azines, tetrazolo-Azines, diazo-Azines, and 1,2,3-triazolo-Azines have been studied at the B3LYP/6-31G(d), B3LYP/6-311++G(d,p) and, for 26 cases, at the G3B3 level. Energies, NICS and bond critical points were used to discuss the ring-chain tautomerism of these compounds in relation with the aromaticity of the Azines (pyridine, pyrimidine, quinazoline, 1,3-diazapyrene, and perimidine) and the azoles (tetrazoles and 1,2,3-triazoles).

  • barriers about double carbon nitrogen bond in imine derivatives aldimines oximes hydrazones Azines
    Croatica Chemica Acta, 2009
    Co-Authors: Fernando Blanco, Ibon Alkorta, Jose Elguero

    Abstract:

    The paper presents the results referring to the inversion mechanism of imines and their derivatives (hydrazones, oximes, Azines). The calculated barriers [B3LYP/6-311++G(d,p) and G3B3)] are in good agreement with the scarce existing data. The transition states correspond in all cases to a pure nitrogen inversion except in the case of Azines where they have some rotation character. The electron properties of the minima and the transition states have been characterized, allowing explanation of the geometrical changes observed in the process.