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In the title compound, C12H16N2O4, intra­molecular N—H⋯O and C—H⋯O hydrogen bonds generate S(6) and S(5) ring motifs, respectively. The nitro group is almost coplanar with the benzene ring, forming a dihedral angle of 6.2 (2)°. In the crystal structure, neighbouring mol­ecules are linked together by inter­molecular N—H⋯O and O⋯O inter­actions. Of interest are the short inter­molecular O⋯O inter­actions which cause a stacking arrangement of the mol­ecules along the a axis.

In the title compound, C10H11N3O2, the nitro group is essentially coplanar with the aromatic ring [dihedral angle = 1.3 (3)°] and forms an intra­molecular amine–nitro N—H⋯O hydrogen bond. In the crystal, weak inter­molecular aromatic C—H⋯Onitro hydrogen bonds link the mol­ecules. Weak aromatic ring π–π inter­actions [minimum ring centroid separation = 3.7744 (13) Å] are also present.

In the title compound, C17H21N3OS, the propyl and butyl groups are disordered over two positions; site occupation factors are 0.304 (10) and 0.696 (10). The three fused rings are coplanar. In the crystal structure, inter­molecular N—H⋯O and C—H⋯O hydrogen bonds link the mol­ecules. Further stability is provided by offset π–π stacking inter­actions. Adjacent thienophene–pyrimidine and pyrimidine–benzene rings have centroid–centroid distances of 3.96 (1) and 3.55 (2) Å, respectively.

In the title compound, C25H25FN4OS, the thienopyrimidine fused-ring system is close to planar (r.m.s. deviation = 0.0089 Å), with a maximum deviation of 0.0261 (17) Å for the N atom adjacent to the benzene ring. This thienopyrimidine fused-ring system forms dihedral angles of 64.73 (3) and 81.56 (5)° with the adjacent benzyl and fluoro­phenyl rings, respectively. Inter­molecular N—H⋯F and C—H⋯F hydrogen bonding, as well as C—F⋯π inter­actions [F⋯centroid = 3.449 (3) Å; C—F⋯centroid = 91.87 (15)°], help to stabilize the crystal structure.

In the title compound, C21H28N2O5 (systematic name: methyl 1,4a-dimethyl-7-nitro-9-oxo-6-propyl­amino-1,2,3,4,4a,9,10,10a-octa­hydro­phenanthrene-1-carboxyl­ate) the cyclo­hexane ring (A) and the central cyclo­hexene ring (B) exist at a trans ring junction, with the two methyl groups in the axial positions of the six-membered rings. Ring A has a chair conformation and ring B a half-chair conformation. An intra­molecular N—H⋯O hydrogen bond occurs. The crystal structure is stabilized by inter­molecular C—H⋯O and N—H⋯O inter­actions.

The title compound, C13H16N4O4, is a new hydrazone. An intra­molecular N—H⋯O hydrogen bond generates a six-membered ring, producing an S(6) ring motif. The nitro groups in the ortho and para positions are almost coplanar with the benzene ring to which they are bound, making dihedral angles of 0.60 (11) and 3.18 (11)°, respectively. Pairs of inter­molecular C—H⋯O hydrogen bonds link neighbouring mol­ecules into inversion dimers with R 2 2(10) motifs. The crystal structure is further stabilized by inter­molecular π–π inter­actions, with a benzene centroid-to-centroid distance of 3.6601 (4) Å.

The title compound, C19H21N3O3S, was synthesized via the aza-Wittig reaction of functionalized imino­phospho­rane with phenyl isocyanate under mild conditions. In the mol­ecule, the fused thienopyrimidine ring system is essentially planar, with a maximum deviation of 0.072 (2) Å, and makes a dihedral angle of 60.11 (9)° with the phenyl ring. An intra­molecular C—H⋯O hydrogen bond is present. The crystal packing is stabilized by inter­molecular N—H⋯O and C—H⋯O hydrogen bonds.

In the title mol­ecule, C15H14N2O2, the substituted benzene ring forms a dihedral angle of 4.15 (1)° with the benzimidazole ring system. An intra­molecular O—H⋯N hydrogen bond generates an S(6) ring motif. In the solid state, mol­ecules are linked into chains along the [001] via inter­molecular bifurcated N—H⋯(O,O) hydrogen bonds, which generate R 1 2(5) ring motifs. The crystal packing is also consolidated by C—H⋯π inter­actions, and π–π stacking inter­actions between the imidazole and substituted benzene rings [centroid–centroid distance = 3.5746 (13) Å]. The methyl group attached to the benzimidazole ring system is disordered over two positions with occupancies of 0.587 (6) and 0.413 (6), suggesting 180° rotational disorder for the benzimidazole group.

The title compound, C27H18N4O·2CH4O, is a unsymmetrically substituted quinoxaline. An intra­molecular O—H⋯N hydrogen bond involving the hydr­oxy and imino groups generates an S(6) ring motif. Inter­molecular C—H⋯O and N—H⋯O hydrogen bonds form an R 2 1(7) ring motif involving a methanol O atom and two H atoms of the imidazole and benzene rings, respectively. The latter links neighbouring mol­ecules into one-dimensional extended chains along the a axis. The two benzene rings are inclined towards each other, as indicated by the dihedral angle of 52.13 (10)°. The phenol ring is almost coplanar with the basic quinoxaline unit, making a dihedral angle of 2.43 (6)°. The short distances between the centroids of the five- and six-membered rings prove the existence of π–π inter­actions [centroid–centroid distances = 3.5234 (9)–3.7885 (10) Å]. The crystal structure is stabilized by intra­molecular O—H⋯N, inter­molecular O—H⋯O, N—H⋯O and C—H⋯O (× 2) hydrogen bonds and weak inter­molecular C—H⋯π and π–π inter­actions.

In the title compound, C24H18Cl4N4, the pyrimidine ring makes dihedral angles of 19.1 (2), 4.1 (2) and 67.5 (2)°, respectively, with phenyl and two benzene rings, and the mol­ecular conformation is stabilized by an intra­molecular N—H⋯N hydrogen bond closing a six-membered ring with an S(6) motif. In the crystal, a pair of inter­molecular N—H⋯N hydrogen bonds connect two mol­ecules, forming inversion dimers with R 2 2(12) motifs. C—H⋯π inter­actions links the dimers into a chain running along the a-axis direction. There are also π–π stacking inter­actions [centroid–centroid distance = 3.666 (4) Å] between the benzene rings of adjacent chains.

In the title compound, C25H23FN4, the pyrimidine ring makes dihedral angles of 11.3 (2), 24.5 (2) and 70.1 (2)° with the phenyl and two benzene rings, and the mol­ecular conformation is stabilized by an intra­molecular N—H⋯N hydrogen bond with an S(6) ring motif. In the crystal, a pair of weak C—H⋯F hydrogen bonds link two mol­ecules into an inversion dimer with an R 2 2(16) motif. In the dimer, there is also an inter­molecular π–π stacking inter­action [centroid–centroid distance = 3.708 (4) Å] between the fluorinated benzene rings. The dimers are further linked by a C—H⋯π inter­action, so forming a column along the c axis.

In the title compound, C3H5N2 +·C7H4NO4 −, the benzene ring forms a dihedral angle of 40.60 (5)° with the imidizolium ring. The nitro­benzoate anion is approximately planar: the benzene ring makes dihedral angles of 3.8 (3) and 3.2 (1)° with the nitro and carboxyl­ate groups, respectively. In the crystal structure, the cations and anions are linked by inter­molecular N—H⋯O hydrogen bonds, forming a zigzag chain along the b axis.

In the title compound, C19H15N3O3, the anilino and benzamide rings make dihedral angles of 10.66 (16) and 50.39 (16)°, respectively, with the nitro-substituted benzene ring. The nitro group is slightly twisted by 11.49 (17)° with respect to the attached benzene ring. There is an intra­molecular N—H⋯O hydrogen bond forming an S(6) ring. In the crystal, weak inter­molecular N—H⋯O and C—H⋯O hydrogen bonds link the mol­ecules into a chain parallel to the b axis. Futhermore, weak slipped π–π inter­actions [centroid–centroid distance = 3.819 (2) Å, inter­planar distance = 3.567 Å and offset angle [how is the offset angle defined?] = 21°] between the anilino ring and its symmetry-related counterpart may help to stabilize the packing.

In the title compound, C10H11NO3S, there is distorted tetra­hedral geometry around the S atom. The heterocyclic thia­zine ring adopts a half-chair conformation. The ethyl and sulfonyl groups form dihedral angles of 82.53 (13) and 88.91 (9)°, respectively, with the plane formed by the benzothia­zine ring, excluding the S atom; the S atom and the ethyl group lie on opposite sides of the ring. The mol­ecules are linked into dimers by inter­molecular C—H⋯O hydrogen bonds involving benzene C—H and carbonyl O atoms, thus forming eight-membered rings. The dimers are linked into chains via inter­actions of a similar type. There is an intra­molecular C—H⋯O hydrogen bond.

In the mol­ecule of the title compound, C12H16N2O4, an intra­molecular N—H⋯O hydrogen bond results in the formation of a six-membered ring having an envelope conformation. In the crystal structure, a bifurcated intra/intermolecular N—H⋯(O,O) hydrogen bond generates inversion dimers.

In the title mol­ecule, C26H16BrN3O3, the anthracene and benzene mean planes make dihedral angles of 63.79 (2) and 14.67 (2)°, respectively, with the plane of the imidazole ring. In the crystal structure, weak inter­molecular C—H⋯O hydrogen bonds link mol­ecules to form centrosymmetric dimers. Weak π–π stacking inter­actions, with centroid–centroid distances of 3.779 (2) and 3.826 (2) Å, supply additional stabilization. The crystal packing also exhibits short inter­molecular contacts between the nitro groups and Br atoms [Br⋯O = 3.114 (2) Å].

The title compound, C10H10N2O, crystallizes with two independent mol­ecules in the asymmetric unit, having closely comparable geometries. The dihedral angles between the 1H-pyrazole and benzene rings in the two mol­ecules are 39.57 (14) and 41.95 (13)°. The two mol­ecules are each connected to neighbouring mol­ecules by pairs of inter­molecular O—H⋯N hydrogen bonds, forming dimers with R 2 2(8) ring motifs. These dimers are further linked into R 4 4(10) ring motifs by inter­molecular N—H⋯O hydrogen bonds, forming chains along [101]. The crystal structure is further stabilized by a C—H⋯π inter­action.

In the title mol­ecule, C21H14BrFN4O4, the mean planes of the two nitro groups form dihedral angles of 3.1 (2) and 7.1 (5)° with the benzene ring to which they are attached. The dinitro-substituted ring forms dihedral angles of 8.6 (2) and 71.9 (2)° with the bromo- and fluoro-substituted benzene rings, respectively. The dihedral angle between the bromo- and fluoro-substituted benzene rings is 80.6 (2)°. There is an intra­molecular N—H⋯O hydrogen bond. In the crystal, pairs of weak C—H⋯O hydrogen bonds form inversion dimers. In addition, π–π stacking inter­actions between the bromo- and dinitro-substituted rings [centroid–centroid separation = 3.768 (2) Å] are observed.

In the title compound, C17H19N5O5, obtained from the condensation reaction of 4-diethyl­amino-2-hy­droxy­benzalde­hyde and 2,4-dinitro­phenyl­hydrazine, the two benzene rings are twisted by a dihedral angle of 1.75 (12)°. The nitro groups are slightly twisted with the respect to the benzene ring to which they are attached, making dihedral angles of 8.20 (15) and 5.78 (15)°. An intra­molecular O—H⋯N hydrogen bond occurs. In the crystal, mol­ecules are linked by pairs of inter­molecular N—H⋯O hydrogen bonds, forming dimers through R 2 2(12) rings. These dimers are further linked by C—H⋯O and C—H⋯π and weak slipped π–π inter­actions [centroid–centroid distance = 3.743 (2)Å]. One of the ethyl groups is disordered over two positions, with occupancy factors in the ratio 0.72:0.28.

In the title mol­ecule, C17H16N2O3S, the benzothia­zole fragment and the benzene ring form a dihedral angle of 13.8 (4)°, and an intramolecular O—H⋯N hydrogen bond occurs. In the crystal structure, pairs of weak inter­molecular O—H⋯S and C—H⋯(O,O) hydrogen bonds link mol­ecules into centrosymmetric dimers. These dimers are related by translation along the a axis and form stacks via π–π inter­actions, with a short inter­molecular distance of 3.766 (5) Å between the centroids of the benzene and thia­zole rings.

The title compound, C21H25NO2, adopts a Z conformation about the C=C double bond. The mol­ecular structure is stabilized by an intra­molecular N—H⋯O hydrogen bond and the dihedral angle between the aromatic ring planes is 76.04 (12)°. The atoms of the ethyl substituent are disordered over two sets of sites in a 0.60 (2):0.40 (2) ratio.

In the title compound, C9H8O2, an intra­molecular O—H⋯O hydrogen bond generates an S(6) ring. The dihedral angle between the mean plane of the S(6) ring and the benzene ring is 1.89 (2)°. In the crystal, inversion-related mol­ecules are linked by pairs of O—H⋯O hydrogen bonds, forming a cyclic dimers with R 2 2(12) graph-set motif. Weak inter­molecular C—H⋯Ocarbon­yl and C—H⋯Ohy­droxy hydrogen bonds link the dimers into chains along [010], generating two C(6) motifs that overlap three C atoms, forming R 2 2(8) ring motifs.

In the title compound, C19H16ClN5O2, the triazolopyrimidine ring system is essentially planar, with a maximum displacement of 0.021 (4) Å, and forms dihedral angles of 1.09 (9) and 87.74 (9)° with the phenyl and benzene rings, respectively. Short intra­molecular C—H⋯O and C—H⋯N hydrogen-bonding inter­actions occur within the molecule. In the crystal structure, mol­ecules are linked by inter­molecular C—H⋯O hydrogen bonds into chains parallel to the b axis. In addition, π–π stacking inter­actions involving the triazole and pyrimidine rings of adjacent mol­ecules are observed, with centroid–centroid distances of 3.600 (3) Å.

In the title compound, C20H17N3O4, the dihedral angles between the heterocyclic ring and the toluene and nitro­benzene rings are 4.21 (15) and 11.43 (14)°, respectively. The whole mol­ecule is close to planar (r.m.s. deviation for the 27 non-H atoms = 0.171 Å). Two S(6) rings are formed due to intra­molecular C—H⋯O and O—H⋯O hydrogen bonds. In the crystal, inversion dimers linked by pairs of C—H⋯O bonds generate R 2 2(10) loops and further C—H⋯O bonds link the dimers along the b-axis direction. There exist π–π inter­actions between the heterocyclic rings at a centroid–centroid distance of 3.7126 (10) Å and between the centroids of the benzene rings at a distance of 3.8710 (16) Å.

In the title compound, C16H11F3N4OS, the dihedral angle between the aromatic ring systems is 69.15 (10)°. Intra­molecular N—H⋯N and N—H⋯O hydrogen bonds generate S(5) and S(6) rings, respectively. A short N—H⋯F contact also occurs. In the crystal, inversion dimers linked by pairs of N—H⋯O hydrogen bonds generate R 2 2(8) loops. The dimers are linked by N—H⋯F hydrogen bonds, forming polymeric chains propagating in [100]. π–π inter­actions also exist between the centroids of the benzene rings of the 2-oxoindoline group at a distance of 3.543 (3) Å and a short C=O⋯π contact occurs. Two F atoms of the trifluoro­methyl group are disordered over two sets of sites in a 0.517 (8):0.483 (8) ratio.