- Facile synthesis and characterization of symmetric n-[(phenylcarbonyl) carbamothioyl]benzamide thiourea: Experimental and theoretical investigations
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A thiourea derivative, N-[(phenylcarbonyl)carbamothioyl]benzamide, was synthesized and characterized by elemental analysis, thermal analysis, spectroscopic methods (Fourier transform infrared (FTIR), UV-Vis, Raman, matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF), tandem mass spectrometry (MS/MS) and nuclear magnetic resonance (NMR)) and quantum-chemical calculations. The synthetic route was simple and efficient, conducted just by one-step and no purification step was needed. The compound crystallizes in a non-centrosymmetric orthorhombic crystal system with a P212121 space group, with a = 5.06220(10) ?, b = 11.8623(3) ?, c = 21.9682(8) ?. The molecular conformation of the solid is stabilized by the N-H?O intramolecular hydrogen bond, which was present in the X-ray structure and was also found in the optimized geometry. The theoretical analysis showed that this strong interaction remains even when molecules are solvated, i.e., the rotation barrier and the hydrogen bond strength are greater than the solvent stabilization energy. In addition to this hydrogen bond effect, the relative position of phenyl groups has a certain influence on the chemical behavior of this thiourea and probably for other phenylthioureas.
- Silveira, Rafael G.,Cat?o, Anderson J. L.,Cunha, Beatriz N.,Almeida, Fernando,Correa, Rodrigo S.,Diniz, Luan F.,Tenório, Juan C.,Ellena, Javier,Kuznetsov, Aleksey E.,Batista, Alzir A.,Alcantara, Edésio
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- REACTIONS OF 1,3-DIACYLTHIOUREAS WITH METHOXIDE ION AND WITH AMINES
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Rate constants of base-catalyzed methanolysis and dissociation constants in methanol have been determined for benzylthiourea (II), 1,3-diacetylthiourea (III), 1,3-dibenzoylthiourea (IV), and 1-acetyl-3-benzoylthiourea (V).With the diacyl derivatives III and IV, the reaction of methoxide ion with the neutral substrate is accompanied by that of methoxide with the substrate anion (at higher alkoxide concentrations).Above 0.1 mol l-1 CH3O(-), the rate constants are also affected by medium.The rate of the reaction of neutral diacyl derivative is decreased, and that of the reacti on of methoxide with the substrate anion is rapidly increased.The dissociation constant of II is higher than that of acetylthiourea (I) by about one order of magnitude, but the attack of methoxide on the carbonyl group of II is about three times slower than that in I.The benzoyl group at the N1 nitrogen exhibits a greater activating influence (in both the rate and the equilibrium constants) on the other NHCOR group than the acetyl group does.With V the ratio of methanolysis rate constants is 9:1 in favour of the acetyl group.The reaction of diacetyl derivative III with 1-butanamine has been followed in butanamine buffers.At the lowest butanamine concentrations, the reaction is second order in the amine, and the rate-limiting step is the proton transfer from the intermediate to the second amine molecule.At the highest butanamine concentrations the reaction becomes first order in the amine, and the rate limiting step changes to the attack of butanamine on the carbonyl group of diacetyl derivative III.
- Kavalek, Jaromir,Jirman, Josef,Sterba, Vojeslav
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p. 120 - 131
(2007/10/02)
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