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Justo Cobo

Publications and source records attributed to Justo Cobo.

50 records · Page 3Linked to original sources
PubMed2004

Molecular conformation and supramolecular aggregation in two fused pyrazoles: pi-stacked R(2)(2)(6) dimers in 2,8,8-trimethyl-6,7,8,9-tetrahydropyrazolo[2,3-a]quinazolin-6-one, and sheets of alternating R(2(2)12) and R(6)(6)(48) rings in 3-tert-butyl-4',4'-dimethyl-1-phenyl-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-b]pyridine-5-spiro-1'-cyclohexane-2',6'-dione.

In 2,8,8-trimethyl-6,7,8,9-tetrahydropyrazolo[2,3-a]quinazolin-6-one, C(13)H(15)N(3)O, (I), the heterobicyclic system is planar and exhibits peripheral ten pi-electron delocalization. In 3-tert-butyl-4',4'-dimethyl-1-phenyl-4,5,6,7-tetrahydro-1H- pyrazolo[3,4-b]pyridine-5-spiro-1'-cyclohexane-2',6'-dione, C(23)H(25)N(3)O(2), (II), the pyrazole ring exhibits marked bond fixation, while the reduced pyridine ring adopts a half-chair conformation. Molecules of (I) are linked into centrosymmetric R(2)(2)(6) dimers by a single C-H.N hydrogen bond [H.N = 2.50 A, C.N = 3.3397 (17) A and C-H.N = 148 degrees ], and these dimers are linked into chains by a single pi-pi stacking interaction. In (II), the combined action of one N-H.O hydrogen bond [H.O = 2.40 A, N.O = 3.2248 (15) A and N-H.O = 157 degrees ] and one C-H.O hydrogen bond [H.O = 2.48 A, C.O = 3.407 (2) A and C-H.O = 164 degrees ] links the molecules into sheets built from alternating centrosymmetric R(2)(2)(12) and R(6)(6)(48) rings; there is a weak C-H.N interaction [H.N = 2.60 A, C.N = 3.5149 (18) A and C-H.N = 154 degrees ] between molecules in adjacent sheets.

Journal Article↗
PubMed2004

5-Amino-3-tert-butyl-1-(4-nitrophenyl)-1H-pyrazole forms hydrogen-bonded sheets of alternating R2(2)(20) and R6(6)(32) rings.

Molecules of the title compound, C13H16N4O2, are linked by one N-H...O hydrogen bond [H...O = 2.47 A, N...O = 3.326 (2) A and N-H...O = 166 degrees ] and one N-H...N hydrogen bond [H...N = 2.19 A, N...N = 3.063 (2) A and N-H...N = 173 degrees ] into sheets containing alternating R2(2)(20) and R6(6)(32) rings, both types of which are centrosymmetric.

Journal Article↗
PubMed2004

4-Amino-5-(2-hydroxy-4,4-dimethyl-6-oxocyclohexenylmethyl)-1-methyl-2-(methylsulfanyl)pyrimidin-6(1H)-one: hydrogen-bonded chains are pi-stacked in pairs.

Molecules of the title compound, C15H21N3O3S, have a markedly polarized electronic structure; the carbocyclic ring adopts an envelope conformation and the overall molecular conformation appears to be controlled by two intramolecular hydrogen bonds, one each of the O-H...O and N-H...O types. The molecules are linked into C(6) chains by an intermolecular N-H...O hydrogen bond, and pairs of these hydrogen-bonded chains are linked by a pi-pi stacking interaction.

Journal Article↗
PubMed2004

Racemic 5-(4-chlorophenyl)-2-methoxyindeno[1',2':2,3]pyrido[5,6-d]pyrimidine-4,6(3H,5H)-dione-dimethylformamide (1/1) and (5RS,5aSR,10bSR)-10b-hydroxy-2-methoxy-5-(4-methoxyphenyl)-5a,10b-dihydroindeno[1',2':2,3]pyrido[5,6-d]pyrimidine-4,6(3H,5H)-dione-dimethylformamide (1/1): chains of rings generated by N-H...O and C-H...pi(arene) hydrogen bonds.

5-(4-Chlorophenyl)-2-methoxyindeno[1',2':2,3]pyrido[5,6-d]pyrimidine-4,6(3H,5H)-dione crystallizes as a 1:1 dimethylformamide solvate, C21H14ClN3O3.C3H7NO. The heterocyclic molecules contain a planar fused-ring system and they are linked by paired N-H...O hydrogen bonds [H...O = 1.85 A, N.O = 2.735 (4) A and N-H...O = 179 degrees ] into centrosymmetric dimers, which are themselves linked into chains by a single C-H.pi(arene) hydrogen bond. 10b-Hydroxy-2-methoxy-5-(4-methoxyphenyl)-5a,10b-dihydroindeno[1',2':2,3]pyrido[5,6-d]pyrimidine-4,6(3H,5H)-dione also crystallizes as a 1:1 dimethylformamide solvate, C22H19N3O5.C3H7NO. The heterocyclic molecules contain a sharply folded fused-ring system and they are linked by two independent N-H...O hydrogen bonds [H...O = 1.92 and 2.18 A, N...O = 2.801 (2) and 3.051 (2) A, and N-H...O = 175 and 173 degrees ] into chains of rings. In both compounds, the dimethylformamide molecules are pendent from the chains, linked via N-H...O and O-H...O hydrogen bonds, respectively.

Journal Article↗
PubMed2003

2,2'-Methylenebis(3-hydroxy-5,5-dimethylcyclohex-2-en-1-one).

The title compound, C(17)H(24)O(4), crystallizes with two independent molecules, both lying across twofold rotation axes in space group Pccn, in a unit cell whose dimensions closely mimic those of a tetragonal cell. Each molecule contains paired O-H.O hydrogen bonds [H.O = 1.81 and 1.83 A, O.O = 2.640 (2) and 2.642 (2) A, and O-H.O = 168 and 162 degrees ].

Journal Article↗
PubMed2002

5-[N-(1H-Benzotriazol-1-ylmethyl)amino]-3-tert-butyl-1-phenylpyrazole: sheets built from N[bond]H...N, C[bond]H...N and C[bond]H...pi(pyrazole) interactions.

In the title compound, C(20)H(22)N(6), the molecules are linked into a chain of rings by N[bond]H...N [H...N 2.16 A, N...N 2.950 (3) A and N[bond]H...N 149 degrees] and C[bond]H...N [H...N 2.55 A, C...N 3.481 (3) A and C[bond]H...N 165 degrees ] hydrogen bonds, and these chains are linked into sheets by means of C[bond]H...pi(pyrazole) interactions.

Journal Article↗
PubMed2002

The molecular and supramolecular structures of four 1,5,6,10b-tetrahydropyrazolo[1,5-c]quinazolines.

The supramolecular structures of the title compounds, 2-phenyl-5-p-tolyl-1,5,6,10b-tetrahydropyrazolo[1,5-c]quinazoline, C(23)H(21)N(3), (I), 5-(4-bromophenyl)-2-phenyl-1,5,6,10b-tetrahydropyrazolo[1,5-c]quinazoline, C(22)H(18)BrN(3), (II), 2-(4-chlorophenyl)-5-phenyl-1,5,6,10b-tetrahydropyrazolo[1,5-c]quinazoline, C(22)H(18)ClN(3), (III), and 5-(4-bromophenyl)-2-(4-chlorophenyl)-1,5,6,10b-tetrahydropyrazolo[1,5-c]quinazoline, C(22)H(17)BrClN(3), (IV), are of two general types. Compounds (I), (II) and (III) form base-paired dimers via N-H.N hydrogen bonds, where (I) and (II) are isomorphous, while in (IV), there are no conventional hydrogen bonds.

Amino Acids↗
PubMed2002

2-(4-Bromophenyl)-1,2-dihydropyrimido[1,2-a]benzimidazol-4(3H)-one and 4-(4-methylphenyl)-3,4-dihydropyrimido[1,2-a]benzimidazol-2(1H)-one form hydrogen-bonded base-paired dimers.

The title compounds, 2-(4-bromophenyl)-1,2-dihydropyrimido[1,2-a]benzimidazol-4-(3H)-one, C(16)H(12)BrN(3)O, (IVa), and 4-(4-methylphenyl)-3,4-dihydropyrimido[1,2-a]benzimidazol-2-(1H)-one, C(17)H(15)N(3)O, (Vb), both form R(2)(2)(8) centrosymmetric dimers via N-H...N hydrogen bonds. The N...N distance is 2.943(3)A for (IVa) and 2.8481(16)A for (Vb), with the corresponding N-H...N angles being 129 and 167 degree, respectively. However, in other respects, the supramolecular structures of the two compounds differ. Both compounds contain different C-H...pi interactions, in which the C-H...pi(centroid) distances are 2.59 and 2.47A for (IVa) and (Vb), respectively (the latter being a short distance), with C-H...pi(centroid) angles of 158 and 159 degree, respectively. The supramolecular structures also differ, with a short Br...O distance of 3.117(2)A in bromo derivative (IVa), and a C-H...O interaction with a C...O distance of 3.2561(19)A and a C-H...O angle of 127 degree in tolyl system (Vb). The dihydropyrimido part of (Vb) is disordered, with a ratio of the major and minor components of 0.9:0.1. The disorder consists of two non-interchangeable envelope conformers, each with an equatorial tolyl group and an axial methine H atom.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2002

Supramolecular hydrogen-bonded hexamers in two 5-aryl-3-methyl-1-phenyl-1,6,7,8-tetrahydropyrazolo[3,4-b][1,4]diazepines.

In both title compounds, i.e. 3-methyl-1,5-diphenyl-1,6,7,8-tetrahydropyrazolo[3,4-b][1,4]diazepine, C(19)H(18)N(4), (I), and 5-(4-chlorophenyl)-3-methyl-1-phenyl-1,6,7,8-tetrahydropyrazolo[3,4-b][1,4]diazepine, C(19)H(17)ClN(4), (II), an N-H...N hydrogen bond links six molecules to form an R(6)(6)(30) ring. Compound (I) crystallizes in the R3 space group and (II) crystallizes in P1 with three molecules in the asymmetric unit. The molecule of (I) contains a disordered seven-membered ring.

Anti-Anxiety Agents↗
PubMed2001

A comparison of the supramolecular structures of 1-(6-amino-1,3-benzodioxol-5-yl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one and 1-(6-amino-1,3-benzodioxol-5-yl)-3-[4-(N,N-dimethylamino)phenyl]prop-2-en-1-one.

1-(6-amino-1,3-benzodioxol-5-yl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one, C19H19NO6, (I), contains an intramolecular N-H...O hydrogen bond and a weak C-H...O hydrogen bond, which forms a C10 chain motif running parallel to the c axis. The 6-amino-1,3-benzodioxol-5-yl moieties are involved in pi-pi stacking. 1-(6-amino-1,3-benzodioxol-5-yl)-3-[4-(N,N-dimethylamino)phenyl]prop-2-en-1-one, C18H18N2O3, (II), crystallizes with two molecules in the asymmetric unit. The main feature of the supramolecular structure of (II) is the formation of a centrosymmetric hydrogen-bonded tetramer with an R8(4)(16) motif.

Crystallography, X-Ray↗
PubMed2001

Supramolecular structures of 5-[3-(4-methylphenyl)- and 5-[3-(4-chlorophenyl)-2-propenylidene]-2,2-dimethyl-1,3-dioxane-4,6-dione.

2,2-dimethyl-5-[3-(4-methylphenyl)-2-propenylidene]-1,3-dioxane-4,6-dione, C16H16O4, crystallizes in the triclinic space group P-1, with two molecules in the asymmetric unit. These molecules and a centrosymmetrically related pair, linked together by weak C-H...O hydrogen bonds, form a tetramer. 5-[3-(4-Chlorophenyl)-2-propenylidene]-2,2-dimethyl-1,3-dioxane-4,6-dione, C15H13ClO4, also crystallizes in the triclinic space group P-1, with one molecule in the asymmetric unit. Centrosymmetrically related molecules are linked together by weak C-H...O hydrogen bonds to form dimers which are further linked by yet another pair of centrosymmetrically related C-H...O hydrogen bonds to form a tube which runs parallel to the a axis.

Journal Article↗