Hydride transfer reactions of 5-(2-alkohybenzylidene) barbituric acids: Synthesis of 2,4,6-trioxoperhydropyrimidine-5-spiro-3′-chromanes

The thermal cyclization of 5-(2-phenoxymethylphenyl-methylene)barbituric acid and its derivatives affords 2,4,6-trioxoperhydropyrimidine-5-spiro-3′-chromanes. The reactions require no catalysts and proceed at temperatures from 118 to 240 °C depending on the substrate activity. These cyclization reactions are analogous to T-reactions of tertiary amines involving the hydride transfer. © 2016 Elsevier Lt

Crystal structures of the two epimers from the unusual thermal C6-epimerization of 5-oxo-1,2,3,5,5a,6,7,9b-octahydro-7,9a-epoxypyrrolo[2,1-a]isoindole-6-carboxylic acid, 5a(RS),6(SR),7(RS),9a(SR),9b(SR) and 5a(RS),6(RS),7(RS),9a(SR),9b(SR)

The isomeric title compounds, C12H13NO4 (Ia) and C12H13NO4 (IIa), the products of an usual thermal C6-epimerization of 5-oxo-1,2,3,5,5a,6,7,9b-octahydro-7,9a-epoxypyrrolo[2,1-a]isoindole-6-carboxylic acid, represent the two different diastereomers and have very similar molecular geometries. The molecules of both compounds comprise a fused tetracyclic system containing four five-membered rings (pyrrolidine, pyrrolidinone, dihydrofuran and tetrahydrofuran), all of which adopt the usual envelope conformations. The dihedral angle between the basal planes of the pyrrolidine and pyrrolidinone rings are 14.3 (2) and 16.50 (11)°, respectively, for (Ia) and (IIa). The nitrogen atom has a slightly pyramidalized geometry [bond-angle sum = 355.9 and 355.3°, for (Ia) and (IIa)], respectively. In the crystal of (Ia), molecules form zigzag-like hydrogen-bonded chains along [010] through strong O - H⋯O hydrogen bonds and are further linked by weak C - H⋯O hydrogen bonds into complex two-tier layers parallel to (100). Unlike (Ia), the crystal of (IIa) contains centrosymmetric cyclic hydrogen-bonded dimers [graph set R 2 2(14)], formed through strong O - H⋯O hydrogen bonds and are further linked by weak C - H⋯O hydrogen bonds into ribbons extending across [101]

Cu(II) crown-tetraphenylporphyrinate: Molecular structure and evaluation of the formation of multinuclear complexes with s-metals

A novel neutral complex of a crown-fused tetraphenylporphyrin was obtained and its structure determined by X-ray analysis. Quantum chemical calculations were performed to establish the possibility of exploiting its crown units for the formation of multinuclear complexes with cations of alkaline and alkaline earth metals. © ISUCT Publishing

Crystal structure of bis{1-phenyl-3-methyl-4-[(quinolin-3-yl)iminomethyl-κN]-1H-pyrazol-5-olato-κO}zinc methanol 2.5-solvate from synchrotron X-ray diffraction

The title compound, [Zn(C20H15N4O)2]·2.5CH3OH, I, was synthesized via the reaction of zinc acetate with the respective ligand and isolated as a methanol solvate, i.e., as I·2.5CH3OH. The crystal structure is triclinic (space group P1), with two complex molecules (A and B) and five methanol solvent molecules in the asymmetric unit. One of the five methanol solvent molecules is disordered over two sets of sites, with an occupancy ratio of 0.75:0.25. Molecules A and B are conformers and distinguished by the conformations of the bidentate 1-phenyl-3-methyl-4-[(quinolin-3-yl)iminomethyl]-1H-pyrazol-5-olate ligands. In both molecules, the zinc cations have distorted tetrahedral coordination spheres, binding the monoanionic ligands through the pyrazololate O and imine N atoms. The two ligands adopt slightly different conformations in terms of the orientation of the terminal phenyl and quinoline substituents with respect to the central pyrazololate moiety. The molecular geometries of A and B are supported by intramolecular C - H⋯O and C - H⋯N hydrogen bonds. In the crystal of I, molecules form dimers both by secondary intermolecular Zn⋯O [3.140 (2)-3.553 (3) Å] and π-π stacking interactions. The dimers are linked by intermolecular hydrogen bonds through the solvent methanol molecules into a three-dimensional network. © Burlov et al. 2017

Quantum-Chemical Simulation of Charge-Transfer Complexes of 2,4,7-Trinitro-9H-fluoren-9-one with Donor Molecules. Crystal and Molecular Structure of the 1 : 1 Complex of 2,4,7-Trinitro-9H-fluoren-9-one with Anthracene

Abstract: Quantum-chemical simulations of charge-transfer complexes of 2,4,7-trinitro-9H-fluoren-9-one with eight donor molecules differing in size and structure of the π-aromatic system have been performed in the scope of the density functional theory approximation, and data on the structure and properties of the complexes have been obtained. The electronic and energy characteristics of the acceptor, donors and the complexes, the average interplanar distances, and the values of charge transfer in the complexes have been obtained, and regularities in the change of these quantities have been elucidated. The crystal and molecular structure of the 1 : 1 complex of 2,4,7-trinitro-9H-fluoren-9-one with anthracene (C13H5N3O7·C14H10) have been determined by means of X-ray diffraction analysis. © 2022, Pleiades Publishing, Ltd

Quantum-Chemical Simulation of the Structure of Charge-Transfer Complexes of 9,10-Phenanthrenequinone Nitro-Derivatives with Phenanthrene. Crystal and Molecular Structure of 1 : 1 Complex of 2,4,7-Trinitro-9,10-phenanthrenequinone with Phenanthrene

Abstract: Data on the structure and properties of charge transfer complexes of nitro derivatives of 9,10-phenanthrenequinone (acceptor) with phenanthrene (donor) were obtained by quantum chemical calculations. The energies of complex formation, the average distances between donor and acceptor planes, and the total charge transfer amounts were calculated. 1,3,6-Trinitro-9,10-phenanthrenequinone was shown to be the strongest acceptor in the studied series. The crystal and molecular structure of the 1 : 1 complex of 2,4,7-trinitro-9,10-phenanthrenequinone with phenanthrene [C14H5N3O8·C14H10] was determined by X-ray structural analysis. © 2020, Pleiades Publishing, Ltd

Synthesis and Structures of 1,3-Dicarbonyl Compounds Based on 9,10-Phenanthrenequinone. Crystal and Molecular Structure of the Lantern-Type Binuclear Copper(II) Complex Cu2[μ2-OOCCH2(C14H8)(CO)2OC2H5]4(NCCH3)2

Abstract: 1,3-Dicarbonyl compounds were synthesized by the reaction of 9,10-phenanthrenequinone with acetylacetone and acetoacetic ester followed by the reduction and were characterized by spectroscopic and quantum-chemical methods. In the crystalline state and in solution, these compounds were found to exist in the keto form. The molecular and crystal structure of the binuclear lantern-type copper(II) carboxylate complex Cu2[μ2-OOCCH2(C14H8)(CO)2OC2H5]4(NCCH3)2, which was formed through the oxidation of the starting 1,3-dicarbonyl compound upon the complexation, was determined by X-ray diffraction. The coordination polyhedron of each copper atom can be described as a (4 + 1) square pyramid with four O atoms of four carboxyl groups at the base and the acetonitrile N atom in the apical position. The formation of the lantern-type dimer is attributed to the μ2-O,O' bidentate-bridging coordination mode of carboxyl groups. © 2019, Pleiades Publishing, Inc

Crystal structure of bis{1-phenyl-3-methyl-4-[(quinolin-3-yl)iminomethyl-κN]-1H-pyrazol-5-olato-κO}zinc methanol 2.5-solvate from synchrotron X-ray diffraction

The title compound, [Zn(C20H15N4O)2]·2.5CH3OH, I, was synthesized via the reaction of zinc acetate with the respective ligand and isolated as a methanol solvate, i.e., as I·2.5CH3OH. The crystal structure is triclinic (space group P1), with two complex molecules (A and B) and five methanol solvent molecules in the asymmetric unit. One of the five methanol solvent molecules is disordered over two sets of sites, with an occupancy ratio of 0.75:0.25. Molecules A and B are conformers and distinguished by the conformations of the bidentate 1-phenyl-3-methyl-4-[(quinolin-3-yl)iminomethyl]-1H-pyrazol-5-olate ligands. In both molecules, the zinc cations have distorted tetrahedral coordination spheres, binding the monoanionic ligands through the pyrazololate O and imine N atoms. The two ligands adopt slightly different conformations in terms of the orientation of the terminal phenyl and quinoline substituents with respect to the central pyrazololate moiety. The molecular geometries of A and B are supported by intramolecular C - H⋯O and C - H⋯N hydrogen bonds. In the crystal of I, molecules form dimers both by secondary intermolecular Zn⋯O [3.140 (2)-3.553 (3) Å] and π-π stacking interactions. The dimers are linked by intermolecular hydrogen bonds through the solvent methanol molecules into a three-dimensional network. © Burlov et al. 2017

Multicomponent Synthesis of 4-Alkyl(Aryl, Hetaryl)-2-alkoxycarbonyl(aroyl, carbamoyl)- 3,6-diamino-5-cyanothieno[2,3-b]pyridines

The condensation of malononitrile with hydrogen sulfide and aldehydes in the presence of triethylamine in ethanol at room temperature afforded 4-alkyl(aryl, hetaryl)-2,6-diamino-3,5-dicyano-4H-thiopyrans. Treatment of the latter in situ with alkali in DMF, followed by addition of an alkylating agent, led to the formation of 4-alkyl(aryl, hetaryl)-2-alkoxycarbonyl(aroyl, carbamoyl)-3,6-diamino-5-cyanothieno[2,3-b]- pyridines. © 2018, Pleiades Publishing, Ltd

Synthesis, molecular and crystalline structure of 2-(alkylsulfanyl)-4-aryl(hetaryl)-5,6,7,8-tetrahydroquinoline-3-carbonitriles

[Figure not available: see fulltext.] The multicomponent reaction of aromatic and heteroaromatic aldehydes, malonodithioamide, 1-(cyclohex-1-en-1-yl)piperidine, and alkylating reagents was studied. A wide range of new 2-(alkylsulfanyl)-4-aryl(hetaryl)-5,6,7,8-tetrahydroquinoline-3-carbonitriles were synthesized, and their molecular and crystalline structures were studied by X-ray structural analysis. © 2019, Springer Science+Business Media, LLC, part of Springer Nature