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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.  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
6.  (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
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.  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
9.  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
10.  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
11.  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
12.  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
13.  (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
14.  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
15.  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
16.  Crystal structure of methyl 6-meth­oxy-11-(4-meth­oxy­phen­yl)-16-methyl-14-phenyl-8,12-dioxa-14,15-di­aza­tetra­cyclo­[,7.013,17]hepta­deca-2(7),3,5,13(17),15-penta­ene-10-carboxyl­ate 
In the title compound, the pyran and pyrone rings adopt slightly distorted half-chair and envelope conformations, respectively. In the crystal, C—H⋯O and π–π inter­actions connect the mol­ecules, forming double layers that stack along the c-axis direction.
In the title compound, C30H28N2O6, the pyran ring adopts a slightly distorted half-chair conformation and the pyrone ring adopts an envelope conformation, with the C atom bearing the carboxyl­ate group as the flap. The pyrazole ring [maximum deviation = 0.002 (2) Å] forms a dihedral angle of 13.2 (1)° with the attached benzene ring. The near-planar atoms of the pyran ring and the pyrazole ring are close to coplanar, the dihedral angles between their mean planes being 6.4 (1)°. The dihedral angle between the pyrone ring and the benzene ring of the chromene unit is 10.7 (1)°. The mol­ecular conformation is stabilized by an intra­molecular C—H⋯O hydrogen bond, which generates an S(6) ring motif. In the crystal, C—H⋯O inter­actions generate supra­molecular chains propagating in [100] and these are connected into double layers that stack along the c-axis direction by weak π–π inter­actions between pyrazole rings [centroid–centroid distance = 3.801 (1) Å].
PMCID: PMC4186142  PMID: 25309159
crystal structure; conformation; crystal packing; chromene
17.  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
18.  (E)-1-(4,4′′-Difluoro-5′-meth­oxy-1,1′:3′,1′′-terphenyl-4′-yl)-3-(6-meth­oxy­naphthalen-2-yl)prop-2-en-1-one 
In the title compound, C33H24F2O3, the central benzene ring makes dihedral angles of 44.71 (10), 47.80 (10) and 63.68 (9)° with the two fluoro-substituted benzene rings and the naphthalene ring system, respectively. In the crystal, mol­ecules are connected via inter­molecular C—H⋯F and C—H⋯O hydrogen bonds. Furthermore, the crystal structure is stabilized by weak C—H⋯π and π–π inter­actions [centroid–centroid distance = 3.6816 (13) Å].
PMCID: PMC3238976  PMID: 22199825
19.  (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
20.  (E)-3-[(2-Hy­droxy-3-meth­oxy­benzyl­idene)amino]­benzoic acid 
In the title compound, C15H13NO4, the dihedral angle between the substituted benzene rings is 9.9 (8)°. Part of the mol­ecule (the salicylaldimine segment) is disordered over two sets of sites, with a refined site-occupancy ratio of 0.550 (14):0.450 (14). Intra­molecular O—H⋯N hydrogen bonds form S(6) ring motifs. In the crystal, pairs of O—H⋯O hydrogen bonds link mol­ecules into centrosymmetric dimers with R 2 2(8) ring motifs. The crystal packing also features C—H⋯π inter­actions.
PMCID: PMC3344025  PMID: 22589934
21.  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
22.  4-Hy­droxy-5-(2-meth­oxy­phen­oxy)-2,2′-bipyrimidin-6(5H)-one dihydrate 
The title compound, C15H12N4O4·2H2O, crystallizes with two independent water mol­ecules in the asymmetric unit. The dihedral angles between the mean planes of the benzene and pyrimidine rings and that of the pyrimidin-4-one ring are 85.1 (9) and 82.1 (1)°, respectively. The mean plane of the pyrimidine ring is twisted by 12.8 (8)° from that of the pyrimidin-4-one ring. The dihedral angles between the benzene ring and the mean planes of the pyrimidine and pyrimidin-4-one rings are 85.1 (9) and 82.1 (1)°, respectively.In the crystal, N–H⋯O, O—H⋯N and O—H⋯O hydrogen bonds involving both water mol­ecules are present; these link the mol­ecules into a two-dimensional network parallel to (010). In addition, weak C—H⋯π and π–π [centroid–centroid distance = 3.6183 (8) Å] inter­actions occur.
PMCID: PMC3884357  PMID: 24454133
23.  (2E)-4-tert-Butyl-2-(4-meth­oxy­benzyl­idene)-3,4-dihydro­naphthalen-1(2H)-one 
In the title compound C22H24O2, the exocyclic C=C double bond is in an E configuration and the tert-butyl group is in an axial position on the cyclo­hexa­none ring. The cyclo­hexa­none ring in the dihydro­naphthalene fused-ring system adopts a half-chair conformation in both independent two mol­ecules in the asymetric unit. The benzene ring system is oriented angles of 43.97 (12) and 39.24 (12)° with respect to the naphthyl ring system in the two independent mol­ecules. In the crystal, mol­ecules are linked via C—H⋯O hydrogen bonds and C—H⋯π inter­actions.
PMCID: PMC3151781  PMID: 21837196
24.  4-Chloro-N′-(4-meth­oxy­benzyl­idene)benzohydrazide methanol monosolvate 
The title compound, C15H13ClN2O2·CH4O, consists of a 4-chloro-N′-(4-meth­oxy­benzyl­idene)benzohydrazide (CMB) mol­ecule and a methanol mol­ecule of crystallization. It was obtained by the condensation of 4-meth­oxy­benzaldehyde with 4-chloro­benzohydrazide. In the CMB mol­ecule, the dihedral angle between the two benzene rings is 50.1 (3)°. The methanol mol­ecule is linked to the CMB mol­ecule through O—H⋯O and O—H⋯N hydrogen bonds. In the crystal, CMB mol­ecules are linked through inter­molecular N—H⋯O hydrogen bonds, involving the methanol mol­ecule, forming chains propagating along [010].
PMCID: PMC3009357  PMID: 21588939
25.  4-[2-(2-Benzyl­idene­hydrazin­ylidene)-3,6-dihydro-2H-1,3,4-thia­diazin-5-yl]-3-(4-meth­oxy­phen­yl)­sydnone 
In the title compound, C19H16N6O3S, the 3,6-dihydro-1,3,4-thia­diazine ring adopts a twist-boat conformation. The dihedral angle between the meth­oxy-substituted benzene ring and the oxadiazole ring is 71.91 (7)°. In the crystal structure, centrosymmetrically related mol­ecules are linked into dimers via pairs of inter­molecular N—H⋯N hydrogen bonds, generating R 2 2(8) ring motifs. There is an intra­molecular C—H⋯O hydrogen bond which generates an S(6) ring motif.
PMCID: PMC3099954  PMID: 21754176

Results 1-25 (211684)