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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.  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
3.  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
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.  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
6.  (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
7.  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
8.  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
9.  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
10.  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
11.  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
12.  4-{2-[2-(4-Chloro­benzyl­idene)hydrazinyl­idene]-3,6-dihydro-2H-1,3,4-thia­diazin-5-yl}-3-(4-meth­oxy­phen­yl)sydnone 
The title compound, C19H15ClN6O3S, exists in trans and cis configurations with respect to the acyclic C=N bonds. The 3,6-dihydro-2H-1,3,4-thia­diazine ring adopts a half-boat conformation. The sydnone ring is approximately planar [maximum deviation = 0.013 (1) Å] and forms dihedral angles of 34.76 (4) and 48.67 (4)° with the benzene rings. An intra­molecular C—H⋯O hydrogen bond stabilizes the mol­ecular structure and forms an S(6) ring motif. In the crystal packing, inter­molecular N—H⋯N hydrogen bonds link centrosymmetrically related mol­ecules into dimers, generating R 2 2(8) ring motifs. The dimers are then linked into a three-dimensional network by inter­molecular C—H⋯O and C—H⋯Cl hydrogen bonds, and by C—H⋯π inter­actions. Further stabilization is provided by π–π inter­actions involving the sydnone rings, with centroid–centroid separations of 3.4198 (5) Å.
PMCID: PMC3089192  PMID: 21754480
13.  6-(4-Chloro­phen­yl)-2-(4-meth­oxy­phen­yl)-6,7-dihydro-4H-pyrazolo­[5,1-c][1,4]oxazine 
In the title compound, C19H17ClN2O2, the pyrazole ring is almost planar with a maximum deviation of 0.009 (3) Å and makes a dihedral angle of 8.96 (9)° with the oxazine ring. The dihedral angles between the pyrazole ring and the chlorine- and meth­oxy-substituted benzene rings are 50.95 (8) and 13.24 (9)°, respectively. An inter­molecular C—H⋯N hydrogen bond links the mol­ecules into infinite chains along the a axis. The crystal structure is further stabilized by C—H⋯π inter­actions.
PMCID: PMC3212334  PMID: 22090991
14.  Ethyl (Z)-2-(2-fluoro­benzyl­idene)-7-methyl-3-oxo-5-phenyl-3,5-dihydro-2H-thia­zolo[3,2-a]pyrimidine-6-carboxyl­ate 
The title compound, C23H19FN2O3S, a fused-pyrimidine derivative, displays dihedral angles between the thia­zole ring and the benzene ring and substituted benzene ring of 7.10 (14) and 3.48 (12)°, respectively. The dihydro­pyrimidine ring adopts a flattened boat conformation. The olefinic double bond is in a Z configuration.
PMCID: PMC3247408  PMID: 22220026
15.  3-{3,5-Bis[(2-but­oxy­eth­oxy)carbon­yl]-2,6-dimethyl-1,4-dihydro­pyridin-4-yl}-1-[(3,4,5-trimeth­oxy­benzo­yl)meth­yl]pyridinium bromide 
In the title salt, C37H51N2O10 +·Br−, the 1,4-dihydro­pyridine (1,4-DHP) ring adopts a slighly puckered boat conformation. The N and opposite C atoms deviate from the least-squares plane calculated through the four other ring atoms by 0.068 (5) and 0.224 (5) Å, respectively. The orientation of both C=O groups is similar (cis with respect to the double bonds of 1,4-DHP. The pyridinium ring has an axial orientation with respect to the1,4-DHP ring and is almost perpendicular to the least-squares plane of the 1,4-DHP ring, making a dihedral angle of 89.2 (3)°. The mol­ecule has a compact shape due to the parallel orientation of the long-chain substituents. One of the but­oxy groups was fond to be disordered (occupancy ratio 0.70:0.30). In the crystal, the bromide anion accepts a weak hydrogen bond from the N—H group of a neighboring 1,4-DHP ring.
PMCID: PMC3588226  PMID: 23476440
16.  (Z)-Ethyl 2-(2,4-dimethyl­benzyl­idene)-7-methyl-3-oxo-5-phenyl-3,5-dihydro-2H-thia­zolo[3,2-a]pyrimidine-6-carboxyl­ate 
In the title compound, C25H24N2O3S, the dihedral angles between the thia­zole ring and the phenyl and substituted benzene rings are 84.91 (11) and 11.58 (10)°, respectively. The dihydro­pyrimidine ring adopts a flattened boat conformation. The olefinic double bond is in a Z configuration.
PMCID: PMC3254473  PMID: 22259414
17.  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
18.  3-(4-Amino­phen­yl)-5-(4-meth­oxy­phen­yl)-4,5-di­hydro-1H-pyrazole-1-carbo­thio­amide 
In the mol­ecule of title pyrazoline derivative, C17H18N4OS, the pyrazole ring adopts an envelope conformation with the flap atom, which bears the meth­oxy­phenyl substituent, displaced by 0.0750 (12) Å from the plane through the other ring atoms. The two substituted benzene rings make a dihedral angle of 70.59 (6)°. The meth­oxy group is twisted slightly with respect to the attached benzene ring [Cmeth­yl—O—C—C torsion angle = −8.84 (15)°]. An intra­molecular N—H⋯N hydrogen bond occurs. In the crystal, the pyrazoline mol­ecules are linked by N—H⋯O and N—H⋯S hydrogen bonds into zigzag layers parallel to the bc plane and stacked along the a axis by π–π inter­actions with centroid–centroid distances of 3.4690 (7) and 3.5792 (7) Å. C—H⋯π inter­actions are also present.
PMCID: PMC3793732  PMID: 24109319
19.  Ethyl 2-(4-carb­oxy­benzyl­idene)-7-methyl-3-oxo-5-phenyl-2,3-dihydro-5H-thia­zolo[3,2-a]pyrimidine-6-carboxyl­ate–N,N-dimethyl­formamide (1/1) 
In the title compound, C24H20N2O5S·C3H7NO, a benzene ring is positioned axially to the pyrimidine ring, which adopts a twist-boat conformation, and is inclined to its mean plane by 85.36 (7)°. In the crystal, inter­molecular C—H⋯O inter­actions result in centrosymmetric head-to-head dimers with an R 2 2(14) graph-set motif along the b axis. Pairs of C—H⋯O and O—H⋯O hydrogen bonds form centrosymmetric head-to-head dimers about inversion centres, corresponding to an R 2 2(7) graph-set motif along the a axis.
PMCID: PMC3275196  PMID: 22347052
20.  (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
21.  3-[Hy­droxy(3-meth­oxy­phen­yl)methyl­idene]-2-(2-oxo-2-phenyl­eth­yl)-3,4-dihydro-2H-1λ6,2-benzothia­zine-1,1,4-trione 
In the title mol­ecule, C24H19NO6S, the heterocyclic thia­zine ring adopts a half-chair conformation with the S and N atoms displaced by 0.180 (5) and 0.497 (5) Å, respectively, on opposite sides of the mean plane formed by the remaining ring atoms. The benzene rings of the benzothia­zine unit and the meth­oxy­phenyl group are almost coplanar, with the dihedral angle between the mean planes of these rings being 5.9 (2)°, while the benzene ring of the 2-oxo-2-phenyl­ethyl group is inclined at 79.68 (11) and 81.01 (10)°, respectively, to these rings. The mol­ecular structure is consolidated by intra­molecular O—H⋯O and C—H⋯N inter­actions, and the crystal packing is stabilized by weak C—H⋯O hydrogen bonds.
PMCID: PMC3343951  PMID: 22590032
22.  Dimethyl 4-[3-(4-meth­oxy­phen­yl)-1-phenyl-1H-pyrazol-4-yl]-2,6-dimethyl-1,4-dihydro­pyridine-3,5-dicarboxyl­ate dihydrate 
In the title compound, C27H27N3O5·2H2O, the dihydro­pyridine ring adopts a flattened boat conformation. The central pyrazole ring is essentially planar [maximum deviation of 0.003 (1) Å] and makes dihedral angles of 50.42 (6) and 26.44 (6)° with the benzene rings. In the crystal, mol­ecules are linked via N—H⋯O, O—H⋯O, O—H⋯N and C—H⋯O hydrogen bonds into two-dimensional networks parallel to the bc plane. The crystal structure is further consolidated by weak C—H⋯π inter­actions.
PMCID: PMC3394006  PMID: 22798871
23.  1-{[(2,3-Dihydro-1H-inden-2-yl)­oxy]meth­yl}quinazoline-2,4(1H,3H)-dione 
In the title mol­ecule, C18H16N2O3, the five-membered ring has an envelope conformation, with the substituted C atom deviating by 0.342 (4) Å from the mean plane P calculated for the remainder of the non-H atoms of the 2,3-dihydro-1H-indene fragment. The mean planes of quinazoline-2,4(1H,3H)-dione fragment and P form a dihedral angle of 59.08 (4)°. In the crystal, pairs of N—H⋯O hydrogen bonds link mol­ecules into inversion dimers, and weak C—H⋯O hydrogen bonds and π–π inter­actions between the benzene rings of the quinazoline ring systems [centroid–centroid distance = 3.538 (3) Å] further consolidate the packing.
PMCID: PMC3379431  PMID: 22719629
24.  1-{[(Cyclo­hexyl­oxy)carbon­yl]­oxy}ethyl 3-{[2′-(2-ethyl-2H-tetra­zol-5-yl)biphenyl-4-yl]meth­yl}-2-oxo-2,3-dihydro-1H-benzimidazole-4-carboxyl­ate 
In the title compound, C33H34N6O6, the dihydro­benzimidazol-2-one ring system is essentially planar (r.m.s. deviation = 0.021 Å). The cyclo­hexane ring adopts a chair conformation. In the 5-(biphenyl-2-yl)-2H-tetra­zole fragment, the tetra­zole ring is twisted away from the attached benzene ring by 35.73 (11)° and the two benzene rings form a dihedral angle of 68.00 (9)°. An intra­molecular C—H⋯O inter­action is observed. In the crystal, the mol­ecules are linked into a zigzag chain running along the b axis by inter­molecular N—H⋯O hydrogen bonds.
PMCID: PMC2983784  PMID: 21580794
25.  Ethyl 5-(4-chloro­phen­yl)-2-[(Z)-(methoxy­carbon­yl)methyl­ene]-7-methyl-3-oxo-3,5-dihydro-2H-thia­zolo[3,2-a]pyrimi­dine-6-carboxyl­ate 
The title compound, C19H17ClN2O5S, was synthesized by the reaction of ethyl 6-(4-chloro­phen­yl)-2-mercapto-4-methyl-1,6-dihydro­pyrimidine-5-carboxyl­ate and dimethyl acetyl­ene­dicarboxyl­ate in methanol. In the mol­ecule, the nearly planar thia­zole ring, with a mean deviation from the plane of 0.0108 (3) Å, is fused with a dihydro­pyrimidine ring in a flattened half-chair conformation.
PMCID: PMC2968292  PMID: 21581973

Results 1-25 (252602)