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author:("Kant, raji")
1.  Crystal structure of bis­(3-bromo­pyridine-κN)bis­(O-ethyl di­thio­carbonato-κ2 S,S′)nickel(II) 
In the title mol­ecular complex, [Ni(C3H5OS2)2(C5H4BrN)2], the Ni2+ cation is located on a centre of inversion and has a distorted octa­hedral N2S4 environment defined by two chelating xanthate ligands and two monodentate pyridine ligands. The C—S bond lengths of the thio­carboxyl­ate group are indicative of a delocalized bond and the O—Csp 2 bond is considerably shorter than the O—Csp 3 bond, consistent with a significant contribution of one resonance form of the xanthate anion that features a formal C=O+ unit and a negative charge on each of the S atoms. The packing of the mol­ecules is stabilized by C—H⋯S and C—H⋯π inter­actions. In addition, π–π inter­actions between the pyridine rings [centroid-to-centroid distance = 3.797 (3) Å] are also present. In the crystal structure, mol­ecules are arranged in rows along [100], forming layers parallel to (010) and (001).
doi:10.1107/S2056989014027339
PMCID: PMC4331872
Crystal structure; nickel complex; xanthate ligands; π–π inter­actions; crystal structure
2.  Conformation and crystal structures of 1-amino­cyclo­hexa­neacetic acid (β3,3Ac6c) in N-protected derivatives1  
The gauche conformation of backbone torsion angles (ϕ, θ) for β3,-Ac6c-OH is observed in the N-protected derivatives of 1-amino­cyclo­hexa­neacetic acid.
N-Protected derivatives of 1-amino­cyclo­hexa­neacetic acid (β3,3-Ac6c), namely Valeroyl-β3,3-Ac6c-OH [2-(1-pentanamidocyclohexyl)acetic acid, C13H23NO3], (I), Fmoc-β3,3-Ac6c-OH [2-(1-{[(9H-fluoren-9-yloxy)carbonyl]amino}cyclohexyl)acetic acid, C23H25NO4], (II), and Pyr-β3,3-Ac6c-OH {2-[1-(pyrazine-2-amido)cyclohexyl]acetic acid, C13H17N3O3}, (III), were synthesized and their conformational properties were determined by X-ray diffraction analysis. The backbone torsion angles (ϕ, θ) for β3,3-Ac6c-OH are restricted to gauche conformations in all the derivatives, with a chair conformation of the cyclo­hexane ring. In the crystal structure of (I), the packing of mol­ecules shows both carb­oxy­lic acid R 2 2(8) O—H⋯O and centrosymmetric R 2 2(14) N—H⋯O hydrogen-bonding inter­actions, giving rise to chains along the c-axis direction. In (II), centrosymmetric carb­oxy­lic acid R 2 2(8) O—H⋯O dimers are extended through N—H⋯O hydrogen bonds and together with inter-ring π–π inter­actions between Fmoc groups [ring centroid distance = 3.786 (2) Å], generate a layered structure lying parallel to (010). In the case of compound (III), carb­oxy­lic acid O—H⋯Npyrazine hydrogen bonds give rise to zigzag ribbon structures extending along the c-axis direction.
doi:10.1107/S1600536814020777
PMCID: PMC4257263  PMID: 25484721
crystal structure; disubstituted-β-amino acids; π–π inter­action; hydrogen bonds; conformation
3.  Crystal structure of (4Z)-1-(3,4-di­chloro­phen­yl)-4-[hy­droxy(4-methyl­phen­yl)methyl­idene]-3-methyl-4,5-di­hydro-1H-pyrazol-5-one 
The title compound, C18H14Cl2N2O2, crystallizes with two mol­ecules, A and B, in the asymmetric unit. In mol­ecule A, the dihedral angles between the central pyrazole ring and pendant di­chloro­benzene and p-tolyl rings are 2.18 (16) and 46.78 (16)°, respectively. In mol­ecule B, the equivalent angles are 27.45 (16) and 40.45 (18)°, respectively. Each mol­ecule features an intra­molecular O—H⋯O hydrogen bond, which closes an S(6) ring and mol­ecule A also features a C—H⋯O inter­action. In the crystal, weak C—H⋯π interactions and aromatic π–π stacking [shortest centroid–centroid separation = 3.707 (2) Å] generate a three-dimensional network.
doi:10.1107/S160053681402114X
PMCID: PMC4257223  PMID: 25484715
crystal structure; Schiff-base pyrazole derivative; hydrogen bonding; C—H⋯π inter­actions; aromatic π–π stacking
4.  Crystal structure of 5,5′-[(4-fluoro­phen­yl)methyl­ene]bis­[6-amino-1,3-di­methyl­pyrimidine-2,4(1H,3H)-dione] 
In the title mol­ecule, C19H21FN6O4, the dihedral angles between the benzene ring and essentially planar pyrimidine rings [maximum deviations of 0.036 (2) and 0.056 (2) Å] are 73.32 (7) and 63.81 (8)°. The dihedral angle between the mean planes of the pyrimidine rings is 61.43 (6)°. In the crystal, N—H⋯O hydrogen bonds link mol­ecules, forming a two-dimensional network parallel to (001) and in combination with weak C—H⋯O hydrogen bonds, a three-dimensional network is formed. Weak C—H⋯π inter­actions and π–π inter­actions, with a centroid–centroid distance of 3.599 (2) Å are also observed.
doi:10.1107/S1600536814019886
PMCID: PMC4257154  PMID: 25484692
crystal structure; uracil derivatives; biological activity; pyrimidine scaffolds; bis-uracil derivatives
5.  Crystal structure of 4-[(E)-(4-chloro­benzyl­idene)amino]-3-(2-methyl­benz­yl)-1H-1,2,4-triazole-5(4H)-thione 
In the title mol­ecule, C17H15ClN4S, the benzene rings form dihedral angles of 16.6 (1) and 77.2 (1)° with the triazole ring. The dihedral angle between the benzene rings is 86.6 (1)°. In the crystal, pairs of N—H⋯S hydrogen bonds form inversion dimers with graph-set notation R 2 2(8). Weak C—H⋯S hydrogen bonds link these dimers into layers parallel to (100). Weak intra­molecular C—H⋯S and C—H⋯N contacts are observed.
doi:10.1107/S1600536814018352
PMCID: PMC4186062  PMID: 25309199
crystal structure; Schiff base; 1,2,4-triazole; hydrogen bonding
6.  Crystal structure of (Z)-1-(3,4-dichlorophenyl)-3-methyl-4-[(naphthalen-1-yl­amino)(p-tolyl)methylidene]-1H-pyrazol-5(4H)-one 
The title Schiff base compound, C28H21Cl2N3O, was synthesized by the condensation of 1-(3,4-di­chloro­phen­yl)-3-methyl-4-(4-methyl­benzo­yl)-1H-pyrazol-5(4H)-one with 1-aminona­phthalene. The p-tolyl ring is normal to the pyrazole ring, with a dihedral angle of 88.02 (14)°, and inclined to the naphthalene ring system by 78.60 (12)°. The pyrazole ring is inclined to the naphthalene ring system and the di­chloro-substituted benzene ring by 63.30 (12) and 11.03 (13)°, respectively. The amino group and carbonyl oxygen atom are involved in an intra­molecular N—H⋯O hydrogen bond enclosing an S(6) ring motif. There is also a short C—H⋯O contact involving the carbonyl O atom and the adjacent benzene ring. In the crystal, mol­ecules are linked by C—H⋯π inter­actions, forming a three-dimensional structure.
doi:10.1107/S1600536814017140
PMCID: PMC4186144  PMID: 25309277
crystal structure; Schiff base; naphthalene; pyrazolone; pyrrole
7.  6-Amino-3-methyl-4-(3,4,5-tri­meth­oxy­phen­yl)-2,4-di­hydro­pyrano[2,3-c]pyrazole-5-carbo­nitrile 
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].
doi:10.1107/S1600536814015670
PMCID: PMC4158517  PMID: 25249920
crystal structure
8.  Ethyl 6-amino-5-cyano-4-phenyl-2,4-di­hydro­pyrano[2,3-c]pyrazole-3-carboxyl­ate dimethyl sulfoxide monosolvate 
In the asymmetric unit of the title compound, C16H14N4O3·C2H6OS, there are two independent main mol­ecules (A and B) and two dimethyl sulfoxide solvent mol­ecules. In mol­ecule A, the pyran ring is in a flattened sofa conformation, with the sp 3-hydridized C atom forming the flap. In mol­ecule B, the pyran ring is in a flattened boat conformation, with the sp 3-hydridized C atom and the O atom deviating by 0.073 (3) and 0.055 (3) Å, respectively, from the plane of the other four atoms. The mean planes the pyrazole and phenyl rings form dihedral angles of 84.4 (2) and 84.9 (2)°, respectively, for mol­ecules A and B. In the crystal, N—H⋯O and N—H⋯N hydrogen bonds link the components of the structure into chains along [010]. In both solvent mol­ecules, the S atoms are disordered over two sites, with occupancy ratios of 0.679 (4):0.321 (4) and 0.546 (6):0.454 (6).
doi:10.1107/S1600536814013270
PMCID: PMC4120557  PMID: 25161577
10.  2-[4-(Piperidin-1-yl)-5H-chromeno[2,3-d]pyrimidin-2-yl]phenol 
In the title compound, C22H21N3O2, the pyrimidine ring is essentially planar [maximum deviation = 0.018 (2) Å] and forms dihedral angles of 22.70 (8) and 0.97 (7)°, respectively, with the fused benzene ring and the hy­droxy-substituted benzene ring. The piperidine ring has a chair conformation and the pyran ring has a flattened twist-boat conformation. The hy­droxy group was refined as disordered over two sets of sites in a 0.702 (4):0.298 (4) ratio. The disorder corresponds to a rotation of approxomiately 180° about the C—C bond connecting the phenol group to the pyrimidine ring and hence, both the major and minor components of disorder form intra­molecular O—H⋯N hydrogen bonds. In the crystal, pairs of weak C—H⋯π inter­actions form inversion dimers. In addition, π–π inter­actions are observed between the pyrimidine ring and the hy­droxy-substituted benzene ring [centroid–centroid separation = 3.739 (2) Å].
doi:10.1107/S1600536814005625
PMCID: PMC3998607  PMID: 24826150
11.  5-((Meth­oxy­imino)­{2-[(2-methyl­phen­oxy)meth­yl]phen­yl}meth­yl)-N-phenyl-1,3,4-oxa­diazol-2-amine 
In the title mol­ecule, C24H22N4O3, the plane of the oxa­diazole ring forms a dihedral angle of 32.41 (12)° with that of the phenyl ring and dihedral angles of 74.51 (10) and 56.38 (10)° with the planes of the benzene rings. In the crystal, pairs of N—H⋯N hydrogen bonds link molecules into inversion dimers featuring R 2 2(8) graph-set motifs.
doi:10.1107/S1600536814003821
PMCID: PMC3998470  PMID: 24765044
12.  4-Cyano-3-fluoro­phenyl 4-(hexa­dec­yl­oxy)benzoate 
In the title compound, C30H40FNO3, the dihedral angle between the benzene rings is 57.76 (7)°. The alkyl chain adopts an all-trans conformation. In the crystal, mol­ecules are linked by pairs of C—H⋯O hydrogen bonds, forming inversion dimers.
doi:10.1107/S1600536814001871
PMCID: PMC3998482  PMID: 24764965
13.  Dimethyl 2-[2-(2,4,6-tri­chloro­phen­yl)hydrazin-1-yl­idene]butane­dioate 
In the title compound, C12H11Cl3N2O4, the dihedral angle between the aromatic ring and the hydrazine (NH—N=C) grouping is 52.2 (3)°. The butanedioate groups exhibit planar conformations. An intra­molecular N—H⋯O hydrogen bond links the N—H group of the hydrazine to one of the meth­oxy groups of the butane­dioate moiety. In the crystal, mol­ecules are linked by C—H⋯O hydrogen bonds and π–π inter­actions are also observed [centroid–centroid separation = 3.535 (1) Å].
doi:10.1107/S160053681303242X
PMCID: PMC3914063  PMID: 24526964
14.  5-(5′-Fluoro-2′-meth­oxy­biphenyl-3-yl)-1,3,4-oxa­diazol-2-amine 
In the title compound, C15H12FN3O2, the dihedral angles between the central benzene ring and the pendant benzene and oxa­diazole rings are 45.05 (13) and 15.60 (14)°, respectively. The C atom of the meth­oxy group is roughly coplanar with its attached ring [displacement = 0.178 (4) Å]. In the crystal, N—H⋯N hydrogen bonds link the mol­ecules into [010] chains. Weak C—H⋯π inter­actions are also observed.
doi:10.1107/S1600536813031206
PMCID: PMC3885053  PMID: 24454229
15.  Molecular Docking Study of Conformational Polymorph: Building Block of Crystal Chemistry 
The Scientific World Journal  2013;2013:309710.
Two conformational polymorphs of novel 2-[2-(3-cyano-4,6-dimethyl-2-oxo-2H-pyridin-1-yl)-ethoxy]-4,6-dimethyl nicotinonitrile have been developed. The crystal structure of both polymorphs (1a and 1b) seems to be stabilized by weak interactions. A difference was observed in the packing of both polymorphs. Polymorph 1b has a better binding affinity with the cyclooxygenase (COX-2) receptor than the standard (Nimesulide).
doi:10.1155/2013/309710
PMCID: PMC3821945  PMID: 24250264
16.  (Z)-3-Methyl-4-[1-(4-methyl­anilino)propyl­idene]-1-phenyl-1H-pyrazol-5(4H)-one 
In the title mol­ecule, C20H21N3O, the central pyrazole ring forms dihedral angles of 4.75 (9) and 49.11 (9)°, respectively, with the phenyl and methyl-substituted benzene rings. The dihedral angle between the phenyl and benzene rings is 51.76 (8)°. The amino group and carbonyl O atom are involved in an intra­molecular N—H⋯O hydrogen bond. In the crystal, π–π inter­actions are observed between benzene rings [centroid–centroid seperation = 3.892 (2) Å] and pyrazole rings [centroid–centroid seperation = 3.626 (2) Å], forming chains along [111]. The H atoms of the methyl group on the p-tolyl substituent were refined as disordered over two sets of sites in a 0.60 (4):0.40 (4) ratio.
doi:10.1107/S1600536813019144
PMCID: PMC3793766  PMID: 24109353
17.  (2Z)-3-(2,4-Di­chloro­phen­yl)-3-hy­droxy-N-phenyl­prop-2-ene­thio­amide 
In the title mol­ecule, C15H11Cl2NOS, the dihedral angle between the phenyl and benzene rings is 72.24 (1)°. In the crystal, pairs of N—H⋯S hydrogen bonds form dimers with twofold rotational symmetry. The dimers are connected by weak C—H⋯O hydrogen bonds, forming a two-dimensional network parallel to (001). An intra­molecular O—H⋯S hydrogen bond is also observed.
doi:10.1107/S1600536813017339
PMCID: PMC3770432  PMID: 24046717
18.  2-(1-Amino-4-tert-butyl­cyclo­hex­yl)acetic acid (tBu-β3,3-Ac6c) hemihydrate1  
The title compound, C12H23NO2·0.5H2O, crystallized with two 2-(1-amino-4-tert-butylcyclohexyl)acetic acid mol­ecules, which are present as zwitterions, and one water mol­ecule in the asymmetric unit. The mol­ecular structure of each zwitterion is stabilized by an intra­molecular six-membered (C 6 ) N—H⋯O hydrogen bond. In the crystal, the two independent zwitterions are linked head-to-head by N—H⋯O hydrogen bonds. Further O—H⋯O and N—H⋯O hydrogen bonds link the zwitterions and the water molecules, forming sandwich-like layers, with a hydrophilic filling and a hydrophobic exterior, lying parallel to the ab plane.
doi:10.1107/S1600536813012725
PMCID: PMC3685045  PMID: 23795064
19.  3-Methyl-4-{(E)-[4-(methyl­sulfan­yl)benzyl­idene]amino}-1H-1,2,4-triazole-5(4H)-thione 
In the title mol­ecule, C11H12N4S2, the dihedral angle between the triazole and benzene rings is 21.31 (5)°. A weak intra­molecular C—H⋯S hydrogen bond generates an S(6) ring motif. In the crystal, pairs of N—H⋯S hydrogen bonds form inversion dimers. In addition, π–π inter­actions are observed between the benzene rings, with a centroid–centroid separation of 3.7599 (11) Å.
doi:10.1107/S1600536813009690
PMCID: PMC3648251  PMID: 23723871
20.  4-Amino-3-(3-meth­oxy­benz­yl)-1H-1,2,4-triazole-5(4H)-thione 
In the title mol­ecule, C10H12N4SO, the triazole ring forms a dihedral angle of 73.0 (5)° with the benzene ring. The meth­oxy group is approximtely coplanar with the benzene ring with a C C—O—Cmeth­yl torsion angle of 4.7 (3)°. In the crystal, N—H⋯S hydrogen bonds connect pairs of inversion-related mol­ecules, which are in turn connected by N—H⋯N hydrogen bonds into chains of rings along [010]. Weak C—H⋯O hydrogen bonds connect these chains into a two-dimensional network parallel to (-102).
doi:10.1107/S1600536813009859
PMCID: PMC3648260  PMID: 23723880
21.  (R)-2-Cyano-N-(1-phenyl­eth­yl)acetamide 
In the title compound, C11H12N2O, the dihedral angle between the acetamide group and the benzene ring is 68.7 (1)°. In the crystal, N—H⋯O and weak C—H⋯O hydrogen bonds link the mol­ecules into chains along the a-axis direction.
doi:10.1107/S1600536813008131
PMCID: PMC3647851  PMID: 23723817
22.  Ethyl 2-(quinolin-8-yl­oxy)acetate monohydrate 
In the title compound, C13H13NO3·H2O, the dihedral angle between the ethyl ester group [C—C—O—C(=O); maximum deviation = 0.003 (2) Å] and the quinoline ring system is 7.94 (12)°. The water solvent mol­ecule is linked to the title mol­ecule via O—H⋯O and O—H⋯N hydrogen bonds. In the crystal, mol­ecules are linked by C—H⋯O hydrogen bonds, forming chains propagating along [100].
doi:10.1107/S1600536813008106
PMCID: PMC3629657  PMID: 23634144
23.  5-Bromo-2-chloro­pyrimidin-4-amine 
In the title compound, C4H3BrClN3, the pyrimidine ring is essentially planar (r.m.s. deviation from the plane = 0.087 Å). In the crystal, pairs of N—H⋯N hydrogen bonds connect the mol­ecules into inversion dimers; these are connected by further N—H⋯N hydrogen bonds into a two-dimensional framework parallel to the bc plane.
doi:10.1107/S1600536813007228
PMCID: PMC3629628  PMID: 23634115
24.  Ethyl 2,6-bis­(4-chloro­phen­yl)-4-(4-fluoro­anilino)-1-(4-fluoro­phen­yl)-1,2,5,6-tetra­hydro­pyridine-3-carboxyl­ate 
In the title compound, C32H26Cl2F2N2O2, the tetra­hydro­pyridine ring adopts a distorted boat conformation. The chlorophenyl rings are inclined to one another by 55.2 (1)°, while for the fluorophenyl rings the dihedral angle is 80.7 (1)°. The amino group and carbonyl O atom are involved in an intra­molecular N—H⋯O hydrogen bond. In the crystal, weak C—H⋯O, C—H⋯F and C—H⋯Cl inter­actions link the mol­ecules into a three-dimensional network.
doi:10.1107/S1600536813006090
PMCID: PMC3629536  PMID: 23634054
25.  Ethyl 2,6-bis­(4-chloro­phen­yl)-4-(4-methyl­anilino)-1-(4-methyl­phen­yl)-1,2,5,6-tetra­hydro­pyridine-3-carboxyl­ate 
In the title mol­ecule, C34H32Cl2N2O2, the tetra­hydro­pyridine ring adopts a distorted boat conformation and both 4-chloro­phenyl substituents are in axial positions. An intra­molecular N—H⋯O hydrogen bond is formed by the amino group and carbonyl O atom. In the crystal, weak C—H⋯Cl inter­actions link the mol­ecules into chains along [010].
doi:10.1107/S1600536813005126
PMCID: PMC3588410  PMID: 23476622

Results 1-25 (93)