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Justo Cobo

Publications and source records attributed to Justo Cobo.

At least 19 recordsLinked to original sources
PubMed2006

Hydrogen-bonded chains of rings in methyl 4-[(5-methyl-1H-pyrazol-3-yl)amino]-3-nitrobenzoate and hydrogen-bonded sheets in methyl 1-(5-methyl-1H-pyrazol-3-yl)-1H-benzimidazole-5-carboxylate.

Molecules of methyl 4-[(5-methyl-1H-pyrazol-3-yl)amino]-3-nitrobenzoate, C12H12N4O4, (I), exhibit a polarized (charge-separated) structure in the nitroaniline portion. The molecules are linked into chains of edge-fused R(2)2(16) and R(2)2(22) rings by a combination of N-H...O(carbonyl) and C-H...O(nitro) hydrogen bonds. Methyl 1-(5-methyl-1H-pyrazol-3-yl)-1H-benzimidazole-5-carboxylate, C13H12N4O2, (II), which is readily formed from (I) by reduction followed by ring formation, crystallizes with Z' = 2 in the space group P-1. Each of the two independent molecular types is linked into sheets of R(4)4(28) rings by a combination of N-H...N and C-H...O(carbonyl) hydrogen bonds.

Benzimidazoles↗
PubMed2006

Hydrogen-bonded chains in 3-tert-butyl-5-[(4-methoxybenzyl)amino]-1-phenyl-1H-pyrazole and tetramolecular hydrogen-bonded aggregates in 5-[(benzotriazol-1-ylmethyl)(4-methoxybenzyl)amino]-3-tert-butyl-1-phenyl-1H-pyrazole.

The molecules of 3-tert-butyl-5-[(4-methoxybenzyl)amino]-1-phenyl-1H-pyrazole, C21H25N3O, are linked into simple C9 chains by a single C-H...N hydrogen bond. 5-[(Benzotriazol-1-ylmethyl)(4-methoxybenzyl)amino]-3-tert-butyl-1-phenyl-1H-pyrazole, C28H30N6O, crystallizes with Z' = 2 in the space group P2(1)/c. The molecules are weakly linked into centrosymmetric tetramolecular aggregates by a combination of C-H...N and C-H...O hydrogen bonds.

Journal Article↗
PubMed2006

Three substituted 4-pyrazolylbenzoates: hydrogen-bonded supramolecular structures in one, two and three dimensions.

The molecules of ethyl 4-(5-amino-3-methyl-1H-pyrazol-1-yl)benzoate, C13H15N3O2, are linked by two independent N-H...O hydrogen bonds into a chain of edge-fused and alternating R(4)2(8) and R(2)2(20) rings. A combination of N-H...N and N-H...O hydrogen bonds links the molecules of methyl 4-(5-amino-3-tert-butyl-1H-pyrazol-1-yl)benzoate, C15H19N3O2, into sheets of alternating R(2)2(20) and R(6)6(32) rings. In 4-(5-amino-3-methyl-1H-pyrazol-1-yl)benzoic acid monohydrate, C11H11N3O2.H2O, the molecular components are linked into a three-dimensional framework structure by a combination of five independent hydrogen bonds, two of O-H...N type and one each of O-H...O, N-H...O and N-H...N types.

Azo Compounds↗
PubMed2006

3-[5-(4-Bromophenyl)-1H-pyrazol-3-ylamino]-5,5-dimethylcyclohex-2-en-1-one-(Z)-3-(4-bromophenyl)-3-chloroacrylonitrile (2/1): a stoichiometric cocrystal of a reaction product with one of its early precursors.

The title compound, 2C17H18BrN3O.C9H5BrClN, was crystallized from the reaction between 5,5-dimethylcyclohexane-1,3-dione, triethyl orthoformate and 5-amino-3-(4-bromophenyl)pyrazole, which had itself been prepared from the reaction between (Z)-3-(4-bromophenyl)-3-chloroacrylonitrile and hydrazine. The compound is a stoichiometric 2:1 cocrystal of the reaction product 3-[5-(4-bromophenyl)-1H-pyrazol-3-ylamino]-5,5-dimethylcyclohex-2-en-1-one and the early reactant (Z)-3-(4-bromophenyl)-3-chloroacrylonitrile. The two independent molecules of cyclohex-2-en-1-one are linked by N-H...N and N-H...O hydrogen bonds into complex bilayers and the molecules of acrylonitrile are trapped within large cavities in the substructure formed by the cyclohex-2-en-1-one molecules.

Journal Article↗
PubMed2006

Three substituted (E)-3-aryl-2-(thienyl)acrylonitriles: isolated molecules, simple hydrogen-bonded chains and hydrogen-bonded sheets.

The structure of (E)-2-(2-thienyl)-3-(3,4,5-trimethoxyphenyl)acrylonitrile, C16H15NO3S, contains no direction-specific intermolecular interactions. The molecules of (E)-3-(4-bromophenyl)-2-(2-thienyl)acrylonitrile, C13H8BrNS, exhibit orientational disorder of the thienyl fragment, and the molecules are linked into simple C(5) chains by a single C-H...N hydrogen bond. In (E)-3-phenyl-2-(3-thienyl)acrylonitrile, C13H9NS, the molecules are linked into sheets by a combination of one C-H...N hydrogen bond and one C-H...pi(arene) hydrogen bond.

Journal Article↗
PubMed2006

Three substituted (Z)-5-benzylidene-2-thioxothiazolidin-4-ones: hydrogen-bonded dimers that can be effectively isolated or linked into chains either by aromatic pi-pi stacking interactions or by dipolar carbonyl-carbonyl interactions.

In each of the isomeric compounds (Z)-5-(2-fluorobenzylidene)-2-thioxothiazolidin-4-one, C(10)H(6)FNOS(2), (I), and (Z)-5-(4-fluorobenzylidene)-2-thioxothiazolidin-4-one, C(10)H(6)FNOS(2), (II), there is a very wide C-C-C angle (ca 130 degrees ) at the methine C atom linking the two rings. In each isomer, paired N-H...O hydrogen bonds link the molecules into centrosymmetric R(2)(2)(8) dimers; the hydrogen-bonded dimers are linked into chains by an aromatic pi-pi stacking interaction in isomer (I) and by an antiparallel dipolar carbonyl-carbonyl interaction in isomer (II). (Z)-5-(3,4,5-Trimethoxybenzylidene)-2-thioxothiazolidin-4-one, C(13)H(13)NO(4)S(2), (III), which crystallizes with Z' = 2 in the space group P-1, shows the same very wide angle at the bridging methine C atom; the two independent molecules are linked into an isolated dimer having no crystallographic symmetry.

Journal Article↗
PubMed2006

Four 2-aryl-8,8-dimethyl-6,7,8,9-tetrahydropyrazolo[2,3-a]quinazolin-6-ones: isolated molecules, hydrogen-bonded dimers, and pi-stacked chains of hydrogen-bonded dimers.

In each of the three compounds 2-(4-chlorophenyl)-5,8,8-trimethyl-6,7,8,9-tetrahydropyrazolo[2,3-a]quinazolin-6-one, C19H18ClN3O, (I), 2-(4-methoxyphenyl)-5,8,8-trimethyl-6,7,8,9-tetrahydropyrazolo[2,3-a]quinazolin-6-one, C20H21N3O2, (II), and 8,8-dimethyl-2-(4-methylphenyl)-6,7,8,9-tetrahydropyrazolo[2,3-a]quinazolin-6-one monohydrate, C19H19N3O.H2O, (IV), the non-aromatic carbocyclic ring adopts a half-chair conformation, while in 2-(4-chlorophenyl)-8,8-dimethyl-5-phenyl-6,7,8,9-tetrahydropyrazolo[2,3-a]quinazolin-6-one, C24H20ClN3O, (III), the corresponding ring adopts a conformation intermediate between the envelope and screw-boat forms. The structure of (I) consists of isolated molecules, while that of (II) contains dimers formed by C-H...O hydrogen bonds. In (III), dimers formed by C-H...O hydrogen bonds are linked into chains by means of an aromatic pi-pi stacking interaction, while in the monohydrate, (IV), the heterocyclic molecules and the water molecules are linked by O-H...O and O-H...N hydrogen bonds to form centrosymmetric four-component aggregates.

Crystallography, X-Ray↗
PubMed2006

4,5,6-Triamino-2-(methylsulfanyl)pyrimidine: pi-stacked hydrogen-bonded sheets of R2/2(8), R2/2(10) and R6/6(32) rings.

In the title compound, C5H9N5S, the three independent C-NH2 units are all somewhat pyramidal. The molecules are linked by a combination of one N-H...S and two N-H...N hydrogen bonds into sheets containing three types of ring motif, viz. R(2)(2)(8), R(2)(2)(10) and R(6)(6)(32), all of them centrosymmetric. Adjacent sheets are linked by a single pi-pi stacking interaction.

Crystallography, X-Ray↗
PubMed2006

Isolated molecules in 2-ethylsulfanyl-7-methyl-4-(4-methylphenyl)pyrazolo[1,5-a][1,3,5]triazine and hydrogen-bonded sheets of R2/2(10), R2/2(16), R4/4(22) and R4/4(24) rings in 2-ethylsulfanyl-7-methyl-4-(4-nitrophenyl)pyrazolo[1,5-a][1,3,5]triazine.

In each of 2-ethylsulfanyl-7-methyl-4-(4-methylphenyl)pyrazolo[1,5-a][1,3,5]triazine, C15H16N4S, (I), and 2-ethylsulfanyl-7-methyl-4-(4-nitrophenyl)pyrazolo[1,5-a][1,3,5]triazine, C14H13N5O2S, (II), there is significant bond fixation in the heterocyclic component. While there are no direction-specific intermolecular interactions in the structure of (I), the molecules of (II) are linked by a combination of C-H...O and C-H...S hydrogen bonds into sheets containing four types of ring, all centrosymmetric.

Crystallography, X-Ray↗