Yunus Akçamur

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.

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.

Reaktionen cyclischer Oxalylverbindungen, 34. Mitt.: Synthese von Dibenzoylacet-N-carboxyalkylamiden und semiempirische Rechnungen zur Keto-Enol Tautomerie

Summary4-Benzoyl-5-phenylfuran-2,3-dione (1) and the urethanes2 combine under loss of carbon monoxide yielding the open chain dibenzoylacetic acid derivatives3 and4. 3a, b only can be cyclized to the oxazinone5. The keto-enole tautomerism3 ⇌4 is further investigated with aid of semiempirical quantum chemical calculations, based upon the molecular geometry of3a, deduced from an X-ray study.

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.

Preparation and characterization of novel pyrrol-3-ones attached to α/β-amino acids, esters and amides

Summary.Various α/β amino acid derivatives 5 were attached to compounds 3 to yield 2,3-dihydro-1H-pyrrol-3-ones amino acids derivatives 6. This rare heterocyclic amino acid skeleton including the pyrrolo[1,2-b][1,3]oxazol moiety was also successfully prepared in the esteric form. The structure of the new compounds was characterized by spectroscopic methods.

Synthesis, structural and spectral studies of N-p-methylbenzyliden-N-phenyl-p,p′-dimethoxybenzoyl acetic acid hydrazide

Abstract The structure of the organic derivative of N-p-methylbenzyliden-N-phenyl-p,p′-dimethoxybenzoyl acetic acid hydrazide, [C32H28N2O5], has been determined by X-ray diffraction. The structure derived from the NMR spectroscopy, the IR spectra and elemental analysis is consistent with that of the X-ray diffraction. The compound crystalizes in the monoclinic system with space group P21/c, a = 16.234(1), b = 9.399(2), c = 19.389(1), β = 110.924(3)°, V = 2763.3(5) Å3 and Z = 4. In the crystal, there is one weak C—H…O type intermolecular hydrogen bond interaction.

Methyl (+/-)-1-ethyl-2-hydroxy-4-(4-methoxybenzoyl)-5-(4-methoxyphenyl)-3-oxo-2,3-dihydro-1H-pyrrole-2-acetate.

The title compound, C(24)H(25)NO(7), is a racemic mixture of 2,3-dihydro-1H-pyrrol-3-ones. It crystallizes in the triclinic system, space group P1, with Z = 2. The asymmetric unit contains two enantiomorphic molecules and the structure is stabilized by hydrogen-bond contacts.

Structure and characterization of methyl (±)-1-(2-aminophenyl)-2-hydroxy-4-(4-methoxybenzoyl)-5-(4-methoxyphenyl)-3-oxo-2,3-dihydro-1H-pyrrole-2-acetate

Abstract The stoichiometry of 1 was derived from the results of elemental analysis, IR, 1H, 13C-NMR, UV-Vis and mass spectroscopic techniques. The structure derived from physico-chemical methods is consistent with that of the X-ray diffraction. The compound crystallizes in the triclinic system, space group P1̅, with a = 9.3895(12), b = 11.3759(11), c = 12.8077(14)Å, α = 103.290(3)° β = 98.110(4)°, γ = 105.545(3)°, V = 1252.4(2)Å3, Z = 2. The molecule has a non-planar configuration. The methoxy carbonylmethyl group exhibits an E-configuration. The crystal structure is stabilized by intermolecular C—H…O, N—H…O and O—H…O contacts.

4-Acetyl-5-methyl-1-phenyl-1H-pyrazole-3-carboxyl­ic acid

In the title compound, C13H12N2O3, the phenyl ring is nearly planar, with a maximum deviation of 0.012 (1) A. The pyrazole ring is planar and forms a 48.45 (5)° dihedral angle with the phenyl ring. There is an intramolecular O—H⋯O hydrogen bond between the hydroxy group and the ketone group. The packing is governed by weak C—H⋯N,O interactions.