Search tips
Search criteria

Results 1-25 (245945)

Clipboard (0)

Related Articles

1.  Methyl 5-(4-hy­droxy-3-meth­oxy­phen­yl)-2-(4-meth­oxy­benzyl­idene)-7-methyl-3-oxo-2,3-dihydro-5H-thia­zolo[3,2-a]pyrimidine-6-carboxyl­ate 
In the title compound, C24H22N2O6S, a pyrimidine ring substituted with 4-hy­droxy-3-meth­oxy­phenyl is fused with a thia­zole ring. The 4-hy­droxy-3-meth­oxy­phenyl group is positioned axially to the pyrimidine ring, making a dihedral angle 85.36 (7)°. The pyrimidine ring adopts a twist boat conformation. In the crystal, O—H⋯N inter­actions result in a chain running along the b axis. The carbonyl O atom bonded to the thia­zole ring is involved in two C—H⋯O hydrogen-bond inter­actions forming centrosymmetric dimers; the ten- and six-membered rings resulting from these inter­actions have R 2 2(10) and R 1 2(6) motifs, respectively.
PMCID: PMC3239076  PMID: 22199924
2.  Ethyl (2Z)-2-(3-methoxy­benzyl­idene)-7-methyl-3-oxo-5-phenyl-2,3-dihydro-5H-1,3-thia­zolo[3,2-a]pyrimidine-6-carboxyl­ate 
In the title compound, C24H22N2O4S, the central pyrimidine ring is significantly puckered, assuming a conformation inter­mediate between a boat and a screw boat. The nearly planar thia­zole ring (r.m.s. deviation = 0.0258 Å) is fused with the pyriamidine ring, making a dihedral angle of 9.83 (7)°. The carboxyl group is in an extended conformation with an anti-periplanar orientation with respect to the dihydropyrimidine ring. The benzene ring linked at the chiral C atom is perpendicular to the pyrimidine ring [dihedral angle = 85.21 (8)°] whereas the phenyl ring is nearly coplanar, making a dihedral angle of 13.20 (8)°. An intra­molecular C—H⋯S hydrogen bond is observed. The crystal packing is influenced by weak inter­molecular C—H⋯π inter­actions and π–π stacking between the thia­zole and phenyl rings [centroid–centroid distance = 3.9656 (10) Å], which stack the mol­ecules along the c axis.
PMCID: PMC2983585  PMID: 21580360
3.  Crystal structure of ethyl 2-(2-fluoro­benzyl­idene)-5-(4-fluoro­phen­yl)-7-methyl-3-oxo-2,3-di­hydro-5H-1,3-thia­zolo[3,2-a]pyrimidine-6-carb­oxy­late 
In the title mol­ecule, C23H18F2N2O3S, the 4-fluoro-substituted and 2-fluoro-substituted benzene rings form dihedral angles of 88.16 (8) and 23.1 (1)°, respectively, with the thia­zole ring. The pyrimidine ring adopts a flattened sofa conformation with the sp 3-hydridized C atom forming the flap. In the crystal, pairs of weak C—H⋯O hydrogen bonds link mol­ecules related by twofold rotation axes, forming R 2 2(10) rings, which are in turn linked by weak C—H⋯N inter­actions to form chains of rings along [010]. In addition, weak C—H⋯π(arene) inter­actions link the chains into layers parallel to (001) and π–π inter­actions with a centroid–centroid distance of 3.836 (10) Å connect these layers into a three-dimensional network.
PMCID: PMC4257371  PMID: 25553039
crystal structure; fused pyrimidine derivative; fluoro-substituted compound; hydrogen bonding; C—H⋯π inter­actions; π–π inter­actions
4.  Methyl 5-(4-acet­oxy­phen­yl)-2-(2-bromo­benzyl­idine)-7-methyl-3-oxo-2,3-di­hydro-5H-1,3-thia­zolo[3,2-a]pyrimidine-6-carboxyl­ate 
In the title mol­ecule, C24H19BrN2O5S, the pyrimidine ring is in a flattened half-chair conformation and the 4-acet­oxy­phenyl group is substituted axially to this ring. The thia­zole ring is essentially planar [with a maximum deviation of 0.012 (2) Å for the N atom] and forms dihedral angles of 17.65 (13) and 88.95 (11)° with the bromo- and acet­oxy-substituted benzene rings, respectively. The dihedral angle between the benzene rings is 81.84 (13) Å. In the crystal, pairs of weak C—H⋯O hydrogen bonds lead to the formation of inversion dimers. A weak C—H⋯π inter­action and π–π stacking inter­actions with centroid–centroid distances of 3.5903 (14) Å are observed.
PMCID: PMC3793759  PMID: 24109346
5.  3-(3-Meth­oxy­phen­yl)benzo[d]thia­zolo[3,2-a]imidazol-9-ium hydrogen sulfate 
In the title mol­ecular salt, C16H13N2OS+·HSO4 −, the thia­zolo[3,2-a]benzimidazolium ring system is roughly planar [maximum deviation = 0.046 (3) Å] and makes a dihedral angle of 58.22 (11)° with the benzene ring. The meth­oxy group is almost coplanar with its attached benzene ring [Cmeth­yl—O—C—C = −1.6 (5)°]. In the crystal, the cation is linked to the anion by a bifurcated N—H⋯(O,O) hydrogen bond, generating an R 1 2(4) ring motif. The ion pairs are then connected by a C—H⋯O hydrogen bond into inversion dimers and these dimers are further linked by O—H⋯O hydrogen bonds into an infinite tape along [100]. A π–π stacking inter­action [centroid-to-centroid distance = 3.5738 (18) Å] and a short inter­molecular contact [S⋯O = 2.830 (3) Å] are also observed.
PMCID: PMC3414329  PMID: 22904862
6.  N-(4-Meth­oxy­phen­yl)-6-methyl-2-phenyl-5-{[4-(tri­fluoro­meth­yl)anilino]meth­yl}pyrimidin-4-amine 
The title compound, C26H23F3N4O, crystallizes with two symmetry-independent mol­ecules in the asymmetric unit, denoted A and B, which differ mainly in the rotation of the meth­oxy­phenyl ring. The –CF3 group of mol­ecule B is disordered by rotation, with the F atoms split over two sets of sites; the occupancy factor for the major component is 0.853 (4). The dihedral angles between the pyrimidine ring and the attached phenyl, meth­oxy­phenyl and tri­fluoro­methyl­phenyl rings are 8.1 (2), 37.5 (2) and 70.7 (2)°, respectively, in mol­ecule A, and 9.3 (2), 5.3 (2) and 79.7 (2)° in mol­ecule B. An intra­molecular N—H⋯N hydrogen bond occurs in each mol­ecule. In the crystal, two crystallographically independent mol­ecules associate into a dimer via a pair of N—H⋯N hydrogen bonds, with a resulting R 2 2(12) ring motif and π–π stacking inter­actions [centroid–centroid distance = 3.517 (4) Å] between the pyrimidine rings. For the A mol­ecules, there are inter­molecular C—H⋯O hydrogen bonds between an aryl C atom of meth­oxy­phenyl ring and a meth­oxy O atom of an adjacent mol­ecule. A similar inter­action is lacking in the B mol­ecules.
PMCID: PMC3885078  PMID: 24454254
7.  Ethyl 7-methyl-3-oxo-5-phenyl-2-(2,4,6-trimeth­oxy­benzyl­idene)-2,3-dihydro-5H-thia­zolo[3,2-a]pyrimidine-6-carboxyl­ate 
In the title compound, C26H26N2O6S, the benzene ring is positioned axially to the thia­zolopyrimidine ring and bis­ects it with a dihedral angle of 80.94 (7)°. The pyrimidine ring adopts a flattened boat conformation. In the crystal, pairs of bifurcated C—H⋯O hydrogen bonds link the mol­ecules into chains along the c axis.
PMCID: PMC3344148  PMID: 22606151
8.  Crystal structure of ethyl 5-(3-fluoro­phen­yl)-2-[(4-fluoro­phen­yl)methyl­idene]-7-methyl-3-oxo-2H,3H,5H-[1,3]thia­zolo[3,2-a]pyrimidine-6-carboxyl­ate 
In the title mol­ecule, C23H18F2N2O3S, the pyrimidine ring is in a half-chair conformation and the 3-fluoro­phenyl group is in the axial position. The thia­zole ring (r.m.s. deviation = 0.0252 Å) forms dihedral angles of 84.8 (7) and 9.6 (7)° with the 3-fluoro-substituted and 4-fluoro-substituted benzene rings, respectively. In the crystal, weak C—H⋯F and C—H⋯O hydrogen bonds connect mol­ecules, forming zigzag chains along the b axis. In addition π–π stacking inter­actions with a centroid–centroid distance of 3.7633 (9) Å connect these chains into ladders via inversion-related 4-fluoro­phenyl groups.
PMCID: PMC4257247  PMID: 25484821
crystal structure; pyrimidine; thia­zole; hydrogen bonds; π–π stacking inter­actions
9.  14-Hy­droxy-11-[(E)-4-meth­oxy­benzyl­idene]-8-(4-meth­oxy­phen­yl)-5-thia-3,13-diaza­hepta­cyclo­[,13.02,9.02,14.03,7.019,23]tetra­cosa-1(22),15(23),16,18,20-pentaen-10-one 
In the title compound, C36H32N2O4S, the piperidine ring adopts a chair conformation, while the five-membered pyrrolidine (with a C atom as the flap atom) and thia­zolidine (with the S atom as the flap atom) rings adopt envelope conformations. The naphthalene ring system makes dihedral angles of 18.82 (5) and 40.92 (5)° with the two meth­oxy-substituted benzene rings. In the crystal, centrosymmetrically-related mol­ecules are linked into dimers via pairs of C—H⋯O and C—H⋯N hydrogen bonds. An intra­molecular O—H⋯N hydrogen bond is also observed. The crystal structure is further stabilized by C—H⋯π inter­actions.
PMCID: PMC3247613  PMID: 22219918
10.  Ethyl 3-acetyl-4-(3-meth­oxy­phen­yl)-6-methyl-2-sulfanyl­idene-1,2,3,4-tetra­hydro­pyrimidine-5-carboxyl­ate 
In the title compound, C17H20N2O4S, the aryl ring is positioned perpendicular to the dihydro­pyrimidine ring, the dihedral angle between the ring planes being 77.48 (9)°. The carboxyl­ate and methyl groups are in a cis conformation with respect to the C=C bond. The dihydro­pyrimidine ring adopts a twist-boat conformation. The crystal structure is stabilized by N—H⋯O and C—H⋯O inter­actions, the former resulting in mol­ecular chains along the b axis and the latter forming inversion dimers.
PMCID: PMC3344654  PMID: 22590416
11.  N′-[(E)-5-Bromo-2-hy­droxy-3-meth­oxy­benzyl­idene]-4-meth­oxy­benzohydrazide monohydrate 
In the title compound, C16H15BrN2O4·H2O, the hydrazide mol­ecule is nearly planar, with a largest deviation from the mean plane through the non-H atoms of 0.106 (4) Å and a dihedral angle between the benzene rings of 1.98 (16)°. This mol­ecule adopts an E conformation about the C=N bond and an intra­molecular O—H⋯N hydrogen bond increases the rigidity. In the crystal, some mol­ecules of the title hydrazide are replaced by mol­ecules of its 6-bromo isomer, and the Br atom from this admixture mol­ecule was refined to give a partial occupancy of 0.0523 (13). The hydrazide and water mol­ecules are linked through classical N—H⋯O and O—H⋯O hydrogen bonds, forming layers parallel to (110). C—H⋯π inter­actions are also present.
PMCID: PMC3470184  PMID: 23125628
12.  (E)-1-[2-Hy­droxy-4,6-bis­(meth­oxy­meth­oxy)phen­yl]-3-[3-meth­oxy-4-(meth­oxy­meth­oxy)phen­yl]prop-2-en-1-one 
The title compound, C22H26O9, crystallizes with two independent mol­ecules in the asymmetric unit in which the dihedral angles between the two benzene rings are 21.4 (2) and 5.1 (2)°. An intra­molecular O—H⋯O hydrogen bond occurs in each mol­ecule. Inter­molecular C—H⋯O hydrogen bonds stabilize the crystal structure.
PMCID: PMC3247344  PMID: 22219962
13.  Ethyl 2-[2-(4-hy­droxy-3-meth­oxy­benzyl­idene)hydrazin-1-yl­idene]-3,4-dimethyl-2,3-dihydro-1,3-thia­zole-5-carboxyl­ate 
The title compound, C16H19N3O4S, is almost planar, with a dihedral angle of 2.88 (9)° between the mean planes of the benzene and thia­zole rings. The mol­ecule adopts an E conformation about the two C=N bonds, with a C—N—N—C torsion angle of −177.01 (11)°. An intra­molecular C—H⋯O hydrogen bond exists between a thia­zole methyl group and the formic acid ethyl ester carbonyl O atom. In the crystal, mol­ecules are linked by O—-H⋯O hydrogen bonds, forming chains propagating along [2-10]. The chains are linked via C—H⋯O hydrogen bonds with R 2 2(12) ring motifs, forming sheets lying parallel to (12-2). The sheets are further linked through out-of-plane C—H⋯N hydrogen bonds with R 2 2(12) ring motifs and C—H⋯π inter­actions, forming an inter­esting three-dimensional supra­molecular architecture.
PMCID: PMC3515300  PMID: 23284520
14.  N′-[(E)-2-Hy­droxy-5-meth­oxy­benzyl­idene]-2-meth­oxy­benzohydrazide 
The mol­ecule of the title compound, C16H16N2O4, adopts an E conformation about the azomethine C=N double bond. The dihedral angle formed by the benzene rings is 18.88 (9)°. The mol­ecular conformation is stabilized by an intra­molecular O—H⋯N hydrogen bond, which forms an S(6) ring. In the crystal, the mol­ecules are linked into chains parallel to [001] by N—H⋯O hydrogen bonds. The chains are further connected into a three-dimensional network by π–π stacking inter­actions with centroid–centroid distances of 3.6538 (10) and 3.8995 (11) Å.
PMCID: PMC3588809  PMID: 23468774
15.  (E)-3-(8-Benz­yloxy-2,3-dihydro-1,4-benzodioxin-6-yl)-1-[2-hy­droxy-4,6-bis­(meth­oxy­meth­oxy)phen­yl]prop-2-en-1-one 
In the title mol­ecule, C28H28O9, the phenol and the benzene rings adjacent to the α,β-unsaturated ketone unit are inclined at 9.15 (13)° to each other. The terminal phenyl ring is oriented with respect to the phenol ring at a dihedral angle of 85.88 (13)°. In the crystal, the methyl­ene C atoms of the dihydro­dioxine ring are disordered over two sites with an occupancy ratio of 0.463 (18):0.537 (18), and both disordered components of the dihydro­dioxine ring adopt twisted-chair conformations. An intra­molecular O—H⋯O hydrogen bond and weak inter­molecular C—H⋯O hydrogen bonds are present in the crystal structure.
PMCID: PMC3100013  PMID: 21754185
16.  (E)-4-Hy­droxy-N′-(3-hy­droxy-4-meth­oxy­benzyl­idene)benzohydrazide 
The mol­ecule of the title benzohydrazide derivative, C15H14N2O4, exists in a trans conformation with respect to the C=N double bond and is twisted, the dihedral angle between the two benzene rings being 24.17 (6)°. The meth­oxy group is almost co-planar with respect to the attached benzene ring [Cm—O—C—C (m = meth­yl) = −1.45 (17)°]. In the crystal, the mol­ecules are linked by N—H⋯O and O—H⋯O hydrogen bonds into sheets parallel to the bc plane. These sheets are further connected into a three-dimensional network by weak C—H⋯O and C—H⋯π inter­actions.
PMCID: PMC3201407  PMID: 22064732
17.  (E)-N′-(3-Hy­droxy-4-meth­oxy­benzyl­idene)-4-meth­oxy­benzohydrazide 
The title mol­ecule, a benzohydrazide derivative, C16H16N2O4, is twisted with a dihedral angle of 69.97 (5)° between the two benzene rings. An intra­molecular O—H⋯O hydrogen bond generates an S(5) ring motif. In the crystal, mol­ecules are linked by N—H⋯O and weak C—H⋯O hydrogen bonds into a chain along the c axis. C—H⋯π inter­actions are also present.
PMCID: PMC3239014  PMID: 22199863
18.  1-[4-(Difluoro­meth­oxy)phen­yl]-N-(3,4-dimeth­oxy­phen­yl)-1H-1,2,4-triazole-3-carboxamide 
Two crystallographically independent mol­ecules, A and B, with similar conformations are present in the asymmetric unit of the title compound, C18H16F2N4O4. In mol­ecule A, the plane of the 1,2,4-triazole ring is tilted relative of the 4-difluoro­meth­oxy-substituted and the 3,4-dimeth­oxy-substituted benzene rings by 6.5 (2) and 16.4 (1)°, respectively. The –CHF2 group is twisted away from the plane of the benzene ring, with a dihedral angle between the O—C bond of the OCHF2 group and the plane of the adjacent phenyl ring of 38.6 (3)°. The corresponding parameters for mol­ecule B are 7.7 (1), 9.5 (2) and 25.2 (2)°. In both mol­ecules, the conformations are stabilized by intra­molecular N—H⋯N and C—H⋯O hydrogen bonds. There are also C—H⋯π contacts between the methyl groups and the benzene rings, and π–π stacking inter­actions between the benzene rings of adjacent parallel A mol­ecules [centroid–centroid distance = 3.8942 (17) Å]. π–π inter­actions are also observed between the triazole ring and one of the benzene rings of parallel B mol­ecules [centroid–centroid distance = 3.7055 (16) Å].
PMCID: PMC3007844  PMID: 21588626
19.  4-(3-Fluoro-4-meth­oxy­phen­yl)-1-(4-meth­oxy­phen­yl)-5-(3,4,5-trimeth­oxy­phen­yl)-1H-imidazole 
In the title mol­ecule, C26H25FN2O5, the fluoro­meth­oxy-, meth­oxy- and trimeth­oxy-substituted benzene rings form dihedral angles of 12.65 (2), 84.15 (2) and 55.67 (2)°, respectively, with the imidazole ring. The crystal structure is stabilized weak inter­molecular C—H⋯F and C—H⋯O hydrogen bonds.
PMCID: PMC3011382  PMID: 21589391
20.  4-[3-(Phen­oxy­meth­yl)-7H-1,2,4-triazolo[3,4-b][1,3,4]thia­diazin-6-yl]-3-(p-tol­yl)sydnone 
In the title triazolothia­diazine derivative, C20H16N6O3S {systematic name: 3-(4-methyl­phen­yl)-4-[3-(phen­oxy­meth­yl)-7H-1,2,4-triazolo[3,4-b][1,3,4]thia­diazin-6-yl]-1,2,3-oxadiazol-3-ium-5-olate}, an S(6) ring motif is generated by an intra­molecular C—H⋯O hydrogen bond. The 3,6-dihydro-1,3,4-thia­diazine ring adopts a twist-boat conformation. The dihedral angle between the 1,2,3-oxadiazole and 1,2,4-triazole rings is 46.45 (14)°. The 1,2,3-oxadiazole ring is inclined at dihedral angle of 59.49 (13)° with respect to the benzene ring attached to it. In the crystal structure, inter­molecular C—H⋯O and C—H⋯N hydrogen bonds link neighbouring mol­ecules into two-mol­ecule-thick arrays parallel to the bc plane. A short S⋯O inter­action [2.9565 (19) Å] also occurs.
PMCID: PMC3007409  PMID: 21588457
21.  1-(4-Meth­oxy­phen­yl)-2-[4-(tri­fluoro­meth­yl)phen­yl]-1H-phenanthro[9,10-d]imidazole 
In the title compound, C29H19F3N2O, a phenanthroline-fused imidazole tetra­cyclic system, the fused benzene rings deviate slightly from the central ring and make dihedral angles with this ring of 3.47 (8) and 3.05 (8)°. The tri­fluoro­methyl­phenyl ring is roughly coplanar with the phenanthroline-fused imidazole tetra­cyclic system [dihedral angle = 11.02 (6)°], while the meth­oxy­phenyl ring is almost perpendicular [dihedral angle = 87.65 (6)°]. There are intra­molecular C—H ⋯π inter­actions involving the meth­oxy­phenyl ring and the central phenanthroline ring, as well as an inter­molecular C—H⋯π inter­action involving the phenanthroline ring. In addition, there is an inter­molecular π–π inter­action involving the central phenanthroline ring and the tri­fluoro­methyl­phenyl ring [centroid–centroid distance = 3.685 (2) Å], as well as C—H⋯N inter­actions linking the mol­ecules into dimers.
PMCID: PMC3793785  PMID: 24109372
22.  4-Meth­oxy-N′-(4-meth­oxy­benzyl­idene)benzohydrazide 
The title compound, C16H16N2O3, was prepared by the reaction of 4-meth­oxy­benzaldehyde with 4-meth­oxy­benzohydrazide in methanol. The dihedral angle between the two benzene rings is 3.1 (3)°. In the crystal, inter­molecular N—H⋯O hydrogen bonds link the mol­ecules into C(4) chains along the b axis.
PMCID: PMC3089322  PMID: 21754485
23.  1-[(Cyclo­propyl­meth­oxy)meth­yl]-6-(3,4-dimeth­oxy­benzyl)-5-ethyl-1,2,3,4-tetra­hydro­pyrimidine-2,4-dione ethanol hemisolvate 
The asymmetric unit of the compound, C20H26N2O5·0.5C2H5OH, consists of two tetra­hydro­pyrimidine-2,4-dione mol­ecules and an ethanol mol­ecule. The pyrimidine rings are nearly planar (r.m.s. deviation = 0.006 Å in one mol­ecule and 0.009 Å in the other); the C atom at the 5-position deviates by 0.083 (3) Å [0.064 (3) Å in the second mol­ecule] from the mean plane and the C atom at the 6-position by 0.034 (3) Å [0.082 (3) Å in the second mol­ecule]. In each mol­ecule, the benzene ring is nearly perpendicular to the pyrimidine ring, the dihedral angle is 88.51 (8)° in one mol­ecule and 84.70 (8)° in the other. The amino group of each tetra­hydro­pyrimidine-2,4-dione mol­ecule is a hydrogen-bond donor to the exocyclic O atom at the 2-position of an adjacent mol­ecule, the hydrogen bond generating an inversion dimer in each case. The ethanol mol­ecule forms a hydrogen bond to the meth­oxy O atom of one of two independent mol­ecules.
PMCID: PMC3275033  PMID: 22346978
24.  N′-(4-Meth­oxy­benzyl­idene)-4-methyl­benzohydrazide 
The title compound, C16H16N2O2, is the product of the reaction of 4-meth­oxy­benzaldehyde and 4-methyl­benzo­hydrazide. The dihedral angle between the substituted benzene rings is 17.6 (3)° and the meth­oxy C atom is almost coplanar with its attached ring [deviation = 0.019 (4) Å]. In the crystal, mol­ecules are linked by N—H⋯O hydrogen bonds, forming C(4) chains propagating along the b-axis direction.
PMCID: PMC3239071  PMID: 22199919
25.  A second monoclinic polymorph for 3-amino-1-(4-meth­oxy­phen­yl)-9,10-dihydro­phenanthrene-2,4-dicarbonitrile 
The title compound, C23H17N3O, has been previously described in a monoclinic P21/c polymorph with Z = 4 [Asiri, Al-Youbi, Faidallah, Ng & Tiekink (2011). Acta Cryst. E67, o2449]. In the new monoclinic P21/n form, with Z = 8, there are two independent mol­ecules, A and B, in the asymmetric unit. In both mol­ecules, the cyclo­hexa-1,3-diene ring has a screw-boat conformation, whereas it is a distorted half-chair in the original polymorph. There is a fold in each mol­ecule, as indicated by the dihedral angle between the benzene rings of the 1,2-dihydro­naphthalene and aniline residues of 33.19 (10)° (mol­ecule A) and 30.6 (10)° (mol­ecule B). The meth­oxy­benzene ring is twisted out of the plane of the aniline residue to which it is connected [dihedral angles = 49.22 (10) and 73.27 (10)°, in A and B respectively]. In the crystal, the two independent mol­ecules self-associate via N—H⋯N hydrogen bonds, generating a 12-membered {⋯HNC3N}2 synthon. These are connected into a supra­molecular tape in the (-101) plane by N—H⋯O(meth­oxy) inter­actions. In the P21/c polymorph, supra­molecular layers are formed by N—H⋯N and N—H⋯O inter­actions.
PMCID: PMC3344100  PMID: 22606103

Results 1-25 (245945)