Molecular structure and tautomerism of 3,5-bis(4-methylpyrazol-1-yl)-4-methylpyrazole

1993 ◽  
Vol 71 (9) ◽  
pp. 1443-1449 ◽  
Author(s):  
Monique Perrin ◽  
Alain Thozet ◽  
Pilar Cabildo ◽  
Rosa Ma Claramunt ◽  
Eduard Valenti ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Potential Surface ◽  
Pyrazole Ring ◽  
Intermolecular Hydrogen Bonds ◽  
Space Group ◽  
Compound C ◽  
Centrosymmetric Dimers

The title compound C12N6H14, 1, crystallizes in the space group P21/n (a = 8.222(2) Å, b = 27.336(8) Å, c = 5.574(2) Å, α = 90.00°, β = 100.97(4)°, γ = 90.00°), Z = 4, d = 1.308 g cm−3. The conformation about the N—C bonds linking the pyrazole rings can be defined as EZ, with "pyridine-like" nitrogen atoms in an anti disposition [Formula: see text] and "pyridine-like" and "pyrrole-like" nitrogen atoms in a syn disposition [Formula: see text] with regard to the central pyrazole. Intermolecular hydrogen bonds between the central and the terminal pyrazole ring of configuration Z form centrosymmetric dimers. They pack in sheets nearly parallel to the (−2 3 1) plane. Its tautomerization barrier has been determined in methanol-d4; the value, 11.9 kcal mol−1, is similar to those of 3,5-dimethyl-4-chloropyrazole (12.8 kcal mol−1) and 3,5-dimethyl-4-nitropyrazole (12.1 kcalmol−1). These values together with the shape of the conformational potential surface (calculated using the AM1 Hamiltonian) suggest that, in compound 1, prototropy and rotation about the N—C bonds linking the three pyrazole rings take place simultaneously.

scholarly journals 2,6-Bis(4-methoxybenzylidene)cyclohexanone

2006 ◽  
Vol 62 (5) ◽  
pp. o1910-o1912 ◽  
Author(s):  
Ray J. Butcher ◽  
H. S. Yathirajan ◽  
B. K. Sarojini ◽  
B. Narayana ◽  
J. Indira
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Photon Absorption ◽  
Intermolecular Hydrogen Bonds ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Compound C ◽  
Centrosymmetric Dimers

The title compound, C22H22O3, demonstrates a two-photon absorption. Its metrical parameters are similar to those of related cyclohexanone derivatives. In the crystal structure, two sets of centrosymmetric dimers formed by weak C—H...O intermolecular hydrogen bonds combine to form molecular tapes along [101].

scholarly journals Crystal structure of 8-hydroxyquinoline: a new monoclinic polymorph

2014 ◽  
Vol 70 (9) ◽  
pp. o924-o925 ◽  
Author(s):  
Raúl Castañeda ◽  
Sofia A. Antal ◽  
Sergiu Draguta ◽  
Tatiana V. Timofeeva ◽  
Victor N. Khrustalev
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Room Temperature ◽  
Three Dimensional ◽  
Solvent Mixture ◽  
Acta Cryst ◽  
Space Group ◽  
Compound C ◽  
Centrosymmetric Dimers

In an attempt to grow 8-hydroxyquinoline–acetaminophen co-crystals from equimolar amounts of conformers in a chloroform–ethanol solvent mixture at room temperature, the title compound, C9H7NO, was obtained. The molecule is planar, with the hydroxy H atom forming an intramolecular O—H...N hydrogen bond. In the crystal, molecules form centrosymmetric dimersviatwo O—H...N hydrogen bonds. Thus, the hydroxy H atoms are involved in bifurcated O—H...N hydrogen bonds, leading to the formation of a central planar four-membered N2H2ring. The dimers are bound by intermolecular π–π stacking [the shortest C...C distance is 3.2997 (17) Å] and C—H...π interactions into a three-dimensional framework. The crystal grown represents a new monoclinic polymorph in the space groupP21/n. The molecular structure of the present monoclinic polymorph is very similar to that of the orthorhombic polymorph (space groupFdd2) studied previously [Roychowdhuryet al.(1978).Acta Cryst.B34, 1047–1048; Banerjee & Saha (1986).Acta Cryst.C42, 1408–1411]. The structures of the two polymorphs are distinguished by the different geometries of the hydrogen-bonded dimers, which in the crystal of the orthorhombic polymorph possess twofold axis symmetry, with the central N2H2ring adopting a butterfly conformation.

scholarly journals (E)-N′-Hydroxy-1,3-diphenyl-4,5-dihydro-1H-pyrazole-5-carboximidamide

2012 ◽  
Vol 68 (6) ◽  
pp. o1661-o1662 ◽  
Author(s):  
Chandra ◽  
N. Srikantamurthy ◽  
K. B. Umesha ◽  
S. Jeyaseelan ◽  
M. Mahendra
Keyword(s):  
Hydrogen Bonds ◽  
Dihedral Angle ◽  
Title Compound ◽  
Pyrazole Ring ◽  
Dihedral Angles ◽  
Compound C ◽  
Benzene Rings ◽  
Phenyl Rings ◽  
A Chain ◽  
Centrosymmetric Dimers

In the molecule of the title compound, C16H16N4O, the pyrazole ring makes dihedral angles of 8.52 (13) and 9.26 (12)° with the phenyl rings. The dihedral angle between the benzene rings is 1.86 (13)°. In the crystal, molecules are linked into centrosymmetric dimers via pairs of O—H...N hydrogen bonds. Weak N—H...N interactions connect the dimers into a chain along the [100] direction. The pyrazole ring adopts a highly flattened envelope conformation.

scholarly journals 1-{3-(4-Chlorophenyl)-5-[4-(propan-2-yl)phenyl]-4,5-dihydro-1H-pyrazol-1-yl}butan-1-one

2014 ◽  
Vol 70 (7) ◽  
pp. o761-o762 ◽  
Author(s):  
B. Narayana ◽  
Vinutha V. Salian ◽  
Balladka K. Sarojini ◽  
Jerry P. Jasinski
Keyword(s):  
Hydrogen Bonds ◽  
Title Compound ◽  
Pyrazole Ring ◽  
Π Interactions ◽  
Envelope Conformation ◽  
Compound C ◽  
Benzene Rings ◽  
Graph Set ◽  
Centrosymmetric Dimers

In the title compound, C22H25ClN2O, the pyrazole ring exhibits an envelope conformation with the methine C atom as the flap. The benzene rings are twisted by 3.3 (5) and 84.6 (5)° from the pyrazole mean plane, and are inclined to each other by 81.4 (4)°. In the crystal, pairs of weak C—H...O hydrogen bonds form centrosymmetric dimers with anR22(16) graph-set motif. C—H...π interactions link the dimers into columns propagating in [100].

scholarly journals Crystal structure of 7β-hydroxyroyleanone isolated fromTaxodium ascendens(B.)

2017 ◽  
Vol 73 (10) ◽  
pp. 1414-1416
Author(s):  
Shicheng Xu ◽  
Xinhua Ma ◽  
Ruifang Ke ◽  
Shihao Deng ◽  
Xinzhou Yang ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Resonant Scattering ◽  
Acta Cryst ◽  
Space Group ◽  
Compound C ◽  
The Absolute ◽  
Absolute Structure

The title compound, C20H28O4[systematic name: (4bS,8aS,10S)-3,10-dihydroxy-2-isopropyl-4b,8,8-trimethyl-4b,5,6,7,8,8a,9,10-octahydrophenanthrene-1,4-dione], is an abietane-type diterpene, which was isolated fromTaxodium ascendens(B.). The compound crystallizes in the chiral space groupP21, but it was not possible to determine the absolute structure of the molecule in the crystal by resonant scattering. The molecular structure is stabilized by two intramolecular O—H...O hydrogen bonds, enclosingS(5) andS(6) ring motifs. In the crystal, molecules are linked by O—H...O and C—H...O hydrogen bonds, forming chains along the [010] direction. The crystal structure of the 10Rstereoisomer of the title compound, isolated from the roots ofPremna obtusifolia(Verbenaceae), has been reported. It crystallized in the chiral space groupP212121, and the absolute structure was determined as (4bS,8aS,10R), by resonant scattering using CuKα radiation [Razaket al.(2010).Acta Cryst.E66, o1566–o1567].

scholarly journals rac-1-[6-Hydroxy-4-(4-methoxyphenyl)-3,6-dimethyl-4,5,6,7-tetrahydro-2H-indazol-5-yl]ethanone

2013 ◽  
Vol 69 (2) ◽  
pp. o243-o243
Author(s):  
Konstantin A. Potekhin ◽  
Rizvan K. Askerov ◽  
Kushvar E. Hajiyeva ◽  
Narmina A. Gadirova ◽  
Shahkaram I. Nazarov
Keyword(s):  
Hydrogen Bonds ◽  
Title Compound ◽  
Pyrazole Ring ◽  
Chair Conformation ◽  
Space Group ◽  
Compound C ◽  
Centrosymmetric Space Group

The title compound, C18H22N2O3, represents a (4S,5R,6S)-stereoisomer, crystallizing as a racemate in a centrosymmetric space group. The six-membered aliphatic ring adopts a half-chair conformation, with the hydroxy- and acetyl-substituted C atoms deviating by 0.458 (2) and −0.366 (2) Å, respectively, from the plane defined by other four ring atoms. The pyrazole ring is essentially planar [r.m.s deviation = 0.004 (2) Å]. In the crystal, the molecules are linked into chains along thebaxis by N—H...N hydrogen bonds. The chains are linked by O—H...N hydrogen bonds into layers parallel to thebcplane.

scholarly journals 2-Methoxy-3-(trimethylsilyl)phenylboronic acid

2013 ◽  
Vol 69 (12) ◽  
pp. o1818-o1818
Author(s):  
Krzysztof Durka ◽  
Sergiusz Luliński ◽  
Janusz Serwatowski
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Phenylboronic Acid ◽  
Columnar Structure ◽  
Stacking Interactions ◽  
Axis Direction ◽  
Compound C ◽  
Centrosymmetric Dimers

The molecular structure of the title compound, C10H17BO3Si, features an intramolecular O—H...O hydrogen bond; the boronic group group has anexo–endoconformation. In the crystal, the molecules interact with each other by O—H...O hydrogen bonds, producing centrosymmetric dimers that are linked by weak π–π stacking interactions featuring specific short B...C contacts [e.g. 3.372 (2) Å], forming an infinite columnar structure aligned along thea-axis direction.

scholarly journals 1-(4-Methoxyphenylsulfonyl)-5-methyl-5-phenylimidazolidine-2,4-dione

2009 ◽  
Vol 65 (6) ◽  
pp. o1207-o1208 ◽  
Author(s):  
Abid Hussain ◽  
Shahid Hameed ◽  
Helen Stoeckli-Evans
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Benzene Ring ◽  
Title Compound ◽  
Phenyl Group ◽  
Monoclinic Space Group ◽  
Asymmetric Unit ◽  
Space Group ◽  
Compound C ◽  
Centrosymmetric Dimers

The title compound, C17H16N2O5S, crystallized in the chiral monoclinic space groupP21, with two enantiomeric molecules (AandB) in the asymmetric unit. It is composed of a methylimidazolidine-2,4-dione unit substituted with a phenyl group and a 4-methoxyphenylsulfonyl group. The benzene ring mean planes are inclined to one another by 22.20 (14)° in moleculeAand by 15.82 (13)° in moleculeB. In the crystal structure, theAandBmolecules are linked by N—H...O hydrogen bonds, forming centrosymmetric dimers. A number of C—H...O interactions are also present in the crystal structure, leading to the formation of a three-dimensinoal network.

scholarly journals 6-Amino-3-methyl-4-(3,4,5-trimethoxyphenyl)-2,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile

2014 ◽  
Vol 70 (8) ◽  
pp. o875-o876 ◽  
Author(s):  
Naresh Sharma ◽  
Goutam Brahmachari ◽  
Bubun Banerjee ◽  
Rajni Kant ◽  
Vivek K. Gupta
Keyword(s):  
Hydrogen Bonds ◽  
Benzene Ring ◽  
Title Compound ◽  
Pyrazole Ring ◽  
Ring System ◽  
Boat Conformation ◽  
Two Dimensional ◽  
Compound C ◽  
Dimensional Network ◽  
Centroid Distance

In the title compound, C17H18N4O4, the dihedral angle between the benzene ring and 2,4-dihydropyrano[2,3-c]pyrazole ring system is 89.41 (7)°. The pyran moiety adopts a strongly flattened boat conformation. In the crystal, molecules are linked by N—H...N, N—H...O, C—H...N and C—H...O hydrogen bonds into an infinite two-dimensional network parallel to (110). There are π–π interactions between the pyrazole rings in neighbouring layers [centroid–centroid distance = 3.621 (1) Å].

3-Bromo-2-bromomethyl-1-phenylsulfonyl-1H-indole

2007 ◽  
Vol 63 (3) ◽  
pp. o1521-o1522
Author(s):  
P. Sakthivel ◽  
K. Sethusankar ◽  
P. Jai Sankar ◽  
P. S. Joseph
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bonds ◽  
Dihedral Angle ◽  
Title Compound ◽  
Phenyl Ring ◽  
Compound C ◽  
The Mean

The phenyl ring in the title compound, C15H11Br2NO2S, makes a dihedral angle of 81.8 (1)° with the mean plane of the indole system. The molecular structure is stabilized by C—H...O hydrogen bonds.

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