İsmail Yıldırım

Reactions of cyclic oxalyl compounds, part 29: A simple synthesis of functionalized 1H-pyrimidines

Summary4-Benzoyl-5-phenylfuran-2,3-dione (1) and the semicarbazones2, ureas and thioureas6, respectively, combine with loss of water and carbondioxide yielding the 1H-pyrimidine derivatives3 and7, respectively, in moderate yields (30–75%). Hydrolysis of3 b leads to the 1-amino-pyrimidine-2-one4.Zusammenfassung4-Benzoyl-5-phenylfuran-2,3-dion (1) cyclisiert mit den Semicarbazonen2 sowie den Harnstoffen bzw. Thioharnstoffen6 unter Verlust von H2O und CO2 zu einer Reihe von 1,4,5-substituierten 1H-Pyrimidinen in Ausbeuten von 30–75%. Die an3 b exemplarisch durchgeführte Hydrolyse liefert die 1-Amino-Verbindung4.

4‐Benzoyl‐1,5‐diphenyl‐1H‐pyrazole‐3‐carboxylic acid methanol solvate

In the title compound, C23H16N2O3·CH4O, the N—N bond distance in the pyrazole ring, which is planar within 0.008 A, is 1.3634 (18) A. The crystal packing is stabilized by O—H⋯O, O—H⋯N and C—H⋯O intermolecular hydrogen bonds.

Theoretical investigations on the mechanism of interaction of 4-formyl furan-2,3-dione and urea

Abstract The electronic structures of the reactants and of the intermediate and final products of reaction between 4-formyl furan-2,3-dione and urea are calculated by the MNDO and AM1 methods. Taking into account that the proper electron and energy states are characteristic of transitional stages, the energy profile of the reaction is discussed. The reaction is initiated by the nucleophilic attack of the nitrogen atom of urea, directed onto the oxygen atom of the furan cycle.

Investigation of the electronic structures of 1,4,5-substituted derivatives of 1H-pyrimidin-2-thione

SummaryConformational analyses and quantum chemical calculations were carried out for 1,4,5-substituted derivatives of 1H-pyrimidin-2-thione with the common skeletonI by means of the methods MMP2 and SCF MO LCAO in the CNDO/2 and MNDO approximations. The analysis of the electron density distribution as a function of the nature of the substitutents was performed on the basis of the data obtained.ZusammenfassungFür eine Reihe von 1,4,5-substituierten Derivaten des 1H-Pyrimidin-2-thions wurden Konformationsanalysen und quantenmechanische Rechnungen durchgeführt. Als Rechenmethoden wurden das MMP2-Verfahren und die SCF-MO-LCAO-Methode in den CNDO/2- und MNDO-Näherungen benutzt. Die Elektronendichteverteilung der untersuchten Verbindungen wurde in Abhängigkeit von den Substituenten analysiert.

Experimental and Theoretical Studies on the Functionalization Reactions of 4-Benzoyl-1,5-Diphenyl-1H-Pyrazole-3-Carboxylic Acid and Acid Chloride with 2,3-Diaminopyridine

The 1H-pyrazole-3-carboxylic acid 2 was converted in good yield (69%) into the corresponding 1H-pyrazole-3-carboxamide 5 via reaction of the acid chloride 3 with 2,3-diaminopyridine (4). A different product, the 3H-imidazo[4,5-b] pyridine derivative 6, was formed from the reaction of 3 with 4 and base in benzene for 5 hours. The structures of the synthesized compounds were determined spectroscopically. The mechanism of the reaction between 3 and 4 was examined theoretically.

Synthesis, spectroscopic and structural characterization of 5-benzoyl-4-phenyl-2-methylthio-1H-pyrimidine with theoretical calculations using density functional theory

In this paper, we will report a combined experimental and theoretical investigation of the molecular structure and spectroscopic parameters (FT-IR, (1)H NMR, (13)C NMR) of 5-benzoyl-4-phenyl-2-methylthio-1H-pyrimidine. The compound crystallizes in the triclinic space group P-1 with Z=2. The molecular geometry was also optimized using density functional theory (DFT/B3LYP) method with the 6-311G(d,p) and 6-311++G(d,p) basis sets in ground state and compared with the experimental data. All the assignments of the theoretical frequencies were performed by potential energy distributions using VEDA 4 program. Information about the size, shape, charge density distribution and site of chemical reactivity of the molecules has been obtained by mapping electron density isosurface with electrostatic potential (ESP). Also, non-linear optical properties of the title compound were performed at B3LYP/6-311++G(d,p) level. The theoretical results showed an excellent agreement with the experimental values.

Synthesis, characterization and vibrational spectra analysis of ethyl (2Z)-2-(2-amino-4-oxo-1,3-oxazol-5(4H)-ylidene)-3-oxo-3-phenylpropanoate.

In the present study, the experimental and theoretical vibrational spectra of ethyl (2Z)-2-(2-amino-4-oxo-1,3-oxazol-5(4H)-ylidene)-3-oxo-3-phenylpropanoate (AOX) were investigated. The experimental FT-IR (400-4000 cm(-1)) and Laser-Raman spectra (100-4000 cm(-1)) of the molecule in the solid phase were recorded. Theoretical vibrational frequencies and geometric parameters (bond lengths, bond angles and torsion angles) were calculated using ab initio Hartree Fock (HF), Density Functional Theory (B3LYP and B3PW91) methods with 6-311++G(d,p) basis set by Gaussian 03 program, for the first time. The computed values of frequencies are scaled using a suitable scale factor to yield good coherence with the observed values. The assignments of the vibrational frequencies were performed by potential energy distribution (PED) analysis by using VEDA 4 program. The theoretical optimized geometric parameters and vibrational frequencies were compared with the corresponding experimental X-ray diffraction data, and they were seen to be in a good agreement with each other. The hydrogen bonding geometry of the molecule was also simulated to evaluate the effect of intermolecular hydrogen bonding on the vibrational frequencies. Also, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies were found.

Methyl 2-methoxy-7-(4-methylbenzoyl)-4-oxo-6-p-tolyl-4H- furo(3,2-c)pyran-3-carboxylate:A combined experimental and theoretical investigation

The title compound, methyl 2-methoxy-7-(4-methylbenzoyl)-4-oxo-6-p-tolyl-4H-furo[3,2-c]pyran-3-carboxylate (C25H20O7), was prepared and characterized by IR and single-crystal X-ray diffraction (XRD). The compound crystallizes in the triclinic space group P −1 with a = 8.9554(9) Å, b = 10.0018(10) Å, c = 12.7454(13) Å, α = 67.678(7)°, β = 89.359(8)° and γ = 88.961(8)°. In addition to the molecular geometry from X-ray experiment, the molecular geometry and vibrational frequencies of the title compound in the ground state have been calculated using semiempirical AM1 and PM3 methods, as well as Hartree-Fock (HF) and density functional (B3LYP) levels of theory with 6–31G(d) basis set. To determine conformational flexibility, molecular energy profile of the title compound was obtained by semi-empirical (AM1) calculations with respect to two selected degrees of torsional freedom, which were varied from −180° to +180° in steps of 10°. Besides, frontier molecular orbitals (FMO) analysis and thermodynamic properties of the title compound were performed by the B3LYP/6–31G(d) method.

Synthesis And Characterization Of Novel Pyrimidine Derivatives From 2,3-Furandiones

Various novel pyrimidine-2(///)-one and pyrimidine-2(///)-thione derivatives 3a-m have been synthesized efficiently in good yields by the treatment of 4-/>-methylbenzoyl-5-/7-methylphenyl-2,3-furandione (la) and 4-(3,4dimethoxybenzoyl)-5-(3,4-dimethoxyphenyl)-2,3-furandione (Ib) with some ureas and thioureas 2. Structures of these compounds 3 were established on the basis of elemental analysis, IR, Ήand C-NMR spectral studies.

3,5-Bis(4-methyl­benzoyl)-2,6-bis(4-methyl­phenyl)-4H-pyran-4-one

The title compound, C35H28O4, is a tetrasubstituted 4H-pyran-4-one with 2,6-bis(p-tolyl) and 3,5-bis(p-toluyl) substituents. The pyran ring is almost planar; the planes of the toluyl substituents are approximately orthogonal to the pyran mean plane [both dihedral angles are equal to 86.2 (1)°], whereas the tolyl planes form with the latter much smaller dihedral angles of 32.5 (1) and 47.2 (1)°. The crystal structure features two intramolecular C—H⋯O contacts and a C—H⋯π(ring) interaction, with an H⋯Cg distance of 2.70 (3) A (Cg is the centroid of one of the benzene rings).