Ethyl 1-sec-butyl-2-(2-hydroxy­phen­yl)-1H-benzimidazole-5-carboxyl­ate 0.25-hydrate

In the title compound, C₂₀H₂₂N₂O₃·0.25H₂O, the water mol­ecule (occupancy 0.25) is disordered across a crystallographic inversion center. The dihedral angle between the hydroxy­phenyl ring and the benzimidazole ring system is 59.31 (9)°. In the crystal structure, mol­ecules are connected by inter­molecular O—H...N and C—H...O hydrogen bonds. The crystal structure is further stabilized by a weak C—H...π inter­action involving the imidazole ring.

(E)-N′-(2-Benzyl­oxybenzyl­idene)isonicotinohydrazide methanol solvate monohydrate

The title compound, C₂₀H₁₇N₃O₂·CH₄O·H₂O, was synthesized by the condensation reaction of 2-benzyl­oxybenzaldehyde with isoniazid (isonicotinic acid hydrazide). The tricyclic compound displays a trans configuration with respect to the C=N double bond. The central benzene ring makes dihedral angles of 8.83 (7) and 70.39 (8)° with the pyridine ring and the terminal benzene ring, respectively. The dihedral angle between the pyridine ring and the terminal benzene ring is 73.11 (8)°. In the crystal structure, mol­ecules are connected by inter­molecular N—H...O, O—H...O, O—H...(N,N) and C—H...O hydrogen bonds, forming a two-dimensional network perpendicular to the a axis.

2-Hydr­oxy-16-[(E)-4-hydr­oxy-3-methoxy­benzyl­idene]-13-(4-hydr­oxy-3-methoxy­phen­yl)-11-methyl-1,11-diaza­penta­cyclo­[12.3.1.0^2,10.0^3,8.0^10,14]octa­deca-3(8),4,6-triene-9,15-dione

In the title compound, C₃₂H₃₀N₂O₇, the piperidone ring adopts a chair conformation and the five-membered ring of the dihydro­indenone ring system adopts an envelope conformation. Intra­molecular O—H...N and C—H...O hydrogen bonds occur. The dihedral angle between the two hydr­oxy-subsituted methoxy­phenyl rings is 71.12 (5)°. In the crystal structure, mol­ecules are connected by inter­molecular O—H...O hydrogen bonds, forming layers parallel to (001). These layers are further connected by C—H...O hydrogen bonds, forming a three-dimensional network.

2-Amino-5-chloro­pyridine–fumaric acid (1/2)

The asymmetric unit of the title compound, C₅H₅ClN₂·0.5C₄H₄O₄, comprises a neutral 2-amino-5-chloro­pyridine mol­ecule and one half of a fumaric acid mol­ecule which lies on an inversion center. The dihedral angle between the pyridine ring and the plane formed by the fumaric acid mol­ecule is 3.22 (8)°. The 2-amino-5-chloro­pyridine mol­ecule is planar, with a maximum deviation of 0.004 (1) Å for the pyridine N atom. In the crystal, the 2-amino-5-chloro­pyridine mol­ecules inter­act with the carboxyl groups of fumaric acid mol­ecules through N—H...O and O—H...N hydrogen bonds, forming centrosymmetric R₂²(8) ring motifs and another N—H...O hydrogen bond links these motifs into a two-dimensional network parallel to (100).

2-Amino-5-chloro­pyridinium salicylate

In the crystal structure of the title salt, C₅H₆ClN₂⁺·C₇H₅O₃⁻, the protonated N atom and the 2-amino group of the cation are hydrogen bonded to the carboxyl­ate O atoms via a pair of N—H...O hydrogen bonds, forming R₂²(8) ring motifs. These motifs are centrosymmetrically paired via N—H...O hydrogen bonds, forming a complementary donor–donor–acceptor–acceptor (DDAA) array. A typical intra­molecular O—H...O hydrogen bond is also observed in the salicylate anion. The crystal structure is further stabilized by weak C—H...π inter­actions.

2-Amino-5-methyl­pyridinium picolinate 0.63-hydrate

The asymmetric unit of the title compound, C₆H₉N₂⁺·C₆H₄NO₂⁻·0.63H₂O, contains two crystallographically independent 2-amino-5-methyl­pyridinium cations, a pair of picolinate anions and two water mol­ecules, one with an occupancy of 0.25. Both the 2-amino-5-methyl­pyridine mol­ecules are protonated at the pyridine N atoms. In the crystal structure, the cations, anions and water mol­ecules are linked via N—H...O, N—H...N and O—H...O hydrogen bonds, as well as by C—H...O contacts, forming a chain along the b axis. In addition, weak π–π inter­actions are observed between pyridinium rings, with centroid–centroid distances of 3.5306 (13) Å.

19-[(E)-4-Chloro­benzyl­idene]-16-(4-chloro­phen­yl)-2-hydr­oxy-1,11-diaza­hexa­cyclo­[15.3.1.0^2,10.0^3,8.0^10,17.0^11,15]henicosa-3(8),4,6-triene-9,18-dione

In the title compound, C₃₂H₂₆Cl₂N₂O₃, the piperidone ring adopts a chair conformation and the proline and pyrrolidine rings adopt envelope conformations. The indane ring system is essentially planar with an r.m.s. deviation of 0.011 Å for the non-H atoms. The dihedral angle between the two chloro-substituted benzene rings is 63.69 (10)°. Intra­molecular C—H...O and N—H...O hydrogen bonds may influence the mol­ecular conformation. In the crystal structure, mol­ecules are connected into layers by weak inter­molecular C—H...O hydrogen bonds.

2-Amino-5-methyl­pyridinium 2-carb­oxy­acetate

In the title mol­ecular salt, C₆H₉N₂⁺·C₃H₃O₄⁻, the cation is essentially planar, with a maximum deviation of 0.010 (3) Å. In the anion, an intra­molecular O—H...O hydrogen bond generates an S(6) ring and results in a folded conformation. In the crystal, the protonated NH group and the 2-amino group of the cation are hydrogen bonded to the carboxyl­ate O atoms of the anion via a pair of N—H...O hydrogen bonds, forming an R²₂(8) ring motif. Weak inter­molecular C—H...O inter­actions help to further stabilize the crystal structure.

11H-Indeno­[1,2-b]quinoxalin-11-one

In the title compound, C₁₅H₈N₂O, the fused ring system is approximately planar, with a maximum deviation of 0.039 (1) Å. In the crystal, weak inter­molecular C—H...O inter­actions help to establish the packing.

2-Amino-5-chloro­pyridinium 2-carb­oxy­acetate

The title salt, C₅H₆ClN₂⁺·C₃H₃O₄⁻, contains two cations and two anions in the asymmetric unit. Both 2-amino-5-chloro­pyridinium ions are protonated at their pyridine N atoms and both hydrogen malonate ions feature an intra­molecular O—H...O hydrogen bond, which generates an S(6) ring motif and results in a folded conformation. In the crystal structure, the cations and anions are linked via N—H...O, O—H...O and C—H...O hydrogen bonds, forming chains propagating in [010], which are cross-linked by further C—H...O inter­actions.