(Z)-3-[(2-Amino-benz-yl)amino]-1-phenyl-but-2-en-1-one.

In the title compound, C17H18N2O, the aromatic rings are almost normal to one another, making a dihedral angle of 89.00 (8)°. There is an intra-molecular N-H⋯O hydrogen bond in the mol-ecule enclosing an S(6) ring motif. In the crystal, mol-ecules are linked by N-H⋯O hydrogen bonds, forming chains along [010].

Allyl 2-(2,2-dimethyl-3a,6a-di-hydro-furo[3,2-d][1,3]dioxol-5-yl)-4-oxo-4H-chromene-3-carboxyl-ate.

In the title compound, C20H18O7, the dioxolane ring adopts an envelope conformation with the dimethyl-substituted C atom as the flap, and its mean plane makes a dihedral angle of 73.25 (2)° with the pyran ring mean plane. The furan ring makes dihedral angles of 67.43 (12) and 6.20 (11)° with the mean plane of the dioxolane and pyran rings, respectively. The O atom attached to the pyran ring deviates by 0.0219 (2) Šfrom its mean plane. In the crystal, mol-ecules are linked via C-H⋯O hydrogen bonds, forming chains along [010] and enclosing R 2 (2)(9) loops. They stack along the a axis with π-π inter-actions involving the 4H-chromene units [centroid-centroid distances of 3.6389 (13) and 3.6555 (13) Å]. The terminal CH2=CH- atoms of the allyl acetate group are disordered over two sets of sites with a refined occupancy ratio of 0.717 (6):0.283 (6).

Methyl 2-(2,2-dimethyl-3a,6a-di-hydro-furo[3,2-d][1,3]dioxol-5-yl)-4-oxo-4H-chromene-3-carboxyl-ate.

In the title mol-ecule, C18H16O7, the dioxolane ring adopts an envelope conformation with the dimethyl-substituted C atom as the flap. The furan ring is almost coplanar with the pyran ring, with a dihedral angle of 1.04 (10)° between the planes, and it makes a dihedral angle of 67.97 (11)° with the mean plane of the dioxolane ring. The latter makes a dihedral angle of 67.15 (10)° with the pyran ring. The O atom attached to the pyran ring deviates by -0.009 (1) Å. The crystal packing features C-H⋯O hydrogen bonds, forming a three-dimensional structure. The meth-oxy-carbonyl atoms are disordered over two positions, with a refined occupancy ratio of 0.508 (18):0.492 (18).

4-Nitro-phenol-piperazine (2/1).

In the title adduct, C6H5NO3·0.5C4H10N2, the piperazine ring possesses inversion symmetry and has a chair conformation. Its mean plane makes a dihedral angle of 65.45 (7)° with the 4-nitro-phenol ring. In the crystal, the piperazine ring is linked to two 4-nitro-phenol mol-ecules via O-H⋯N hydrogen bonds. The mol-ecules are also linked via bifurcated N-H⋯(O,O) hydrogen bonds involving the NO2 O atoms, forming a two-dimensional network lying parallel to (102). The networks are linked via C-H⋯O hydrogen bonds, forming a three-dimensional structure.

2-Methyl-4-(naphthalen-2-yl)-3a-nitro-3,3a,4,9b-tetra-hydro-2H-spiro-[chromeno[3,4-c]pyrrole-1,3'-indolin]-2'-one.

In the title compound, C29H23N3O4, the 2-methylpyrrolidine ring adopts a twist conformation on the N-C bond involving the spiro C atom, while the hydropyran ring adopts an envelope conformation with the methine C atom bonded to the O atom as the flap. The mean plane of the indoline-2-one ring system is almost perpendicular to the mean plane of the pyrrolidine ring, making a dihedral angle of 89.73 (8)°. The latter ring makes dihedral angles of 47.80 (8) with the naphthalene ring system and 32.38 (8)° with the hydropyran ring mean plane. There is an intra-molecular C-H⋯O hydrogen bond involving the indoline-2-one O atom. In the crystal, adjacent mol-ecules are linked via N-H⋯O hydrogen bonds, forming chains propagating along [100]. The chains are linked via weak C-H⋯O hydrogen bonds, forming two-dimensional networks, lying parallel to (101), and consolidated by C-H⋯π inter-actions.

6-(4-Meth-oxy-phen-yl)-6a-nitro-6,6a,6b,7,8,9,10,12a-octa-hydro-spiro-[chromeno[3,4-a]indolizine-12,3'-indolin]-2'-one.

In the title compound, C29H27N3O5, the hydropyran ring adopts an envelope conformation with the methine C atom bearing the para-meth-oxy-benzene ring as the flap. The central pyrrolidine ring has a twist conformation on the N-C bond involving the spiro C atom. The piperidine ring adopts a chair conformation. An intra-molecular C-H⋯O contact closes an S(7) ring. In the crystal, inversion dimers linked by C-H⋯O inter-actions generate R 2 (2)(18) loops and N-H⋯O hydrogen bonds connect the dimers into [100] chains.

8,13,26-Trioxa-23-thia-21-aza-penta-cyclo-[18.6.0.0(2,7).0(14,19).0(21,25)]hexa-cosa-2(7),3,5,14,16,18-hexa-ene.

In the title compound, C21H23NO3S, both the thia-zole and oxazolidine rings adopt twist conformations. The mean plane of the thia-zole ring makes a dihedral angle of 61.02 (7)° with the oxazolidine ring mean plane, and dihedral angles of 22.72 (6) and 75.07 (6)° with the benzene rings. The benzene rings are almost perpendicular to one another, making a dihedral angle of 89.14 (6)°. There are bifurcated intra-molecular C-H⋯O hydrogen bonds in the mol-ecular structure. In the crystal, mol-ecules are linked via C-H⋯π inter-actions, forming chains propagating along [100].

8,11,24-Trioxa-21-thia-19-aza-penta-cyclo-[16.6.0.0(2,7).0(12,17).0(19,23)]tetra-cosa-2(7),3,5,12,14,16-hexa-ene.

In the title compound, C19H19NO3S, the thia-zole and oxazolidine rings each adopt an envelope conformation, with the S and O atoms as the respective flap atoms. The thia-zole and oxazolidine rings (all atoms) make a dihedral angle of 66.39 (11)° while the phenyl rings subtend a dihedral angle of 22.71 (10)°.

2-Amino-4-methyl-pyridinium 2-nitro-benzoate.

In the title mol-ecular salt, C6H9N2 (+)·C7H4NO4 (-), the original pyridine N atom of 2-amino-4-methyl-pyridine is protonated and the carb-oxylic acid group of nitro-benzoic acid is deprotonated. In the crystal, the ions are linked by N-H⋯O hydrogen bonds, forming chains propagating along [001]. The chains are linked via C-H⋯O hydrogen bonds, forming two-dimensional networks lying parallel to the bc plane.

N-tert-Butyl-2-(2,6-di-chloro-phen-yl)imidazo[1,2-a]pyrazin-3-amine.

In the title compound, C16H16Cl2N4, the imidazole ring mean plane makes a dihedral angle of 70.01 (1)° with the phenyl ring. The Cl atoms deviate by -0.0472 (6) and 0.0245 (8) Šfrom the plane of their attached benzene ring. In the crystal, mol-ecules are linked via pairs of C-H⋯N hydrogen bonds, forming inversion dimers.

6a-Nitro-6-phenyl-6,6a,6b,7,8,9,10,12a-octa-hydro-spiro-[chromeno[3,4-a]indol-izine-12,3'-indolin]-2'-one.

In the title compound, C28H25N3O4, the central pyrrolidine ring adopts adopts an envelope conformation with the N atom as the flap and the piperidine ring adopts a chair conformation. The pendant pyrrolidine ring is almost planar (r.m.s. deviation = 0.008 Å). An intra-molecular C-H⋯O inter-action closes an S(6) ring. In the crystal, inversion dimers linked by pairs of N-H⋯O hydrogen bonds generate R 2 (2)(8) loops.

(1S,3'S,3a'R,6'S)-6'-(2-Chloro-phen-yl)-3'-[(2R,3S)-1-(4-meth-oxy-phen-yl)-4-oxo-3-phenyl-azetidin-2-yl]-2-oxo-3',3'a,4',6'-tetra-hydro-2H,2'H-spiro-[ace-naphthyl-ene-1,1'-pyrrolo-[1,2-c][1,3]thia-zole]-2',2'-dicarbo-nitrile.

The mol-ecular conformation of the title compound, C41H29ClN4O3S, is stabilized by intra-molecular C-H⋯O and C-H⋯Cl hydrogen bonds. The thia-zole ring adopts an envelope conformation with the N atom as the flap, while the pyrrolidine ring has a twisted conformation on the N-C bond involving the spiro C atom. The ß la-ctam ring makes dihedral angles of 39.74 (15) and 16.21 (16)° with the mean planes of the thia-zole and pyrrolidine rings, respectively. The thia-zole ring mean plane makes dihedral angles of 23.79 (13) and 70.88 (13) ° with the pyrrolidine and cyclo-pentane rings, respectively, while the pyrrolidine ring makes a dihedral angle of 85.63 (13)° with the cyclo-pentane ring. The O atom attached to the ß la-ctam ring deviates from its mean plane by 0.040 (2) Å, while the O atom attached to the cyclo-pentane ring deviates from its mean plane by 0.132 (2) Å. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds, forming chains along [010], and C-H⋯π and π-π inter-actions [centroid-centroid distance = 3.6928 (17) Å].

Methyl 3,5-bis-[(3-chloro-pyrazin-2-yl)-oxy]benzoate.

In the title compound, C16H10Cl2N4O4, the pyrazine rings make dihedral angles of 67.82 (9) and 75.91 (9)° with the benzene ring, while the dihedral angle between the pyrazine rings is 44.69 (10)°. The meth-oxy-carbonyl group makes a dihedral angle of 16.82 (8)° with the benzene ring to which it is attached. In the crystal, C-H⋯O hydrogen bonds link the mol-ecules, forming chains running along the ab plane.

(Z)-3-(2-Amino-anilino)-1-phenyl-but-2-en-1-one.

In the title compound, C16H16N2O, the phenyl and 2-amino-phenyl rings are almost perpendicular to one another, with a dihedral angle of 82.77 (8)°. There is an intra-molecular N-H⋯O hydrogen bond in the mol-ecule. In the crystal, mol-ecules are linked via N-H⋯O hydrogen bonds forming chains along [001]. There are also C-H⋯π inter-actions present, linking the chains to form a three-dimensional structure.

l-Histidinium p-toluene-sulfonate.

In the title salt, C6H10N3O2 (+)·C7H7O3S(-), the imidazole ring makes a dihedral angle of 70.93 (12)° with the plane of the toluene ring. In the crystal, the ions are linked via N-H⋯O and weak C-H⋯O hydrogen bonds forming two-dimensional networks lying parallel to (001). These networks are linked via C-H⋯π inter-actions, forming a three-dimensional structure.

(E)-3-[4-(Di-fluoro-meth-oxy)-3-hy-droxy-phen-yl]-1-phenyl-prop-2-en-1-one.

In the title compound, C16H12F2O3, the plane of the phenyl ring makes a dihedral angle of 3.22 (8)° with that of the benzene ring. The mol-ecule has an E conformation about the C=C bond. In the crystal, mol-ecules are linked via pairs of O-H⋯O hydrogen bonds, forming inversion dimers which are further consolidated by a pair of C-H⋯O hydrogen bonds. The dimers are linked via C-H⋯O hydrogen bonds, forming columns along the b-axis direction.

8,15-Dioxa-10,13-di-aza-tetra-cyclo-[14.4.0.0(2,7).0(9,14)]icosa-1(16),2,4,6,9(14),10,12,17,19-nona-ene.

The asymmetric unit of the title compound, C16H10N2O2, contains one half-mol-ecule, the complete mol-ecule being generated by twofold rotation symmetry. The plane of the pyrazine ring forms a dihedral angle of 64.87 (6)° with that of the benzene ring, and the planes of the two benzene rings are inclined to one another by 54.20 (6)°. The O atom deviates from the plane of the benzene ring by 0.1549 (8) Å. There are no significant inter-molecular inter-actions in the crystal.

1,3-Bis[(3-chloro-pyrazin-2-yl)-oxy]benzene.

The asymmetric unit of the title compound, C14H8Cl2N4O2, contains one half-mol-ecule, the complete mol-ecule being generated by the operation of a twofold rotation axis. The Cl atom deviates significantly from the plane of the pyrazine ring [0.0215 (4) Å]. The central benzene ring makes a dihedral angle of 72.82 (7)° with the plane of the pyrazine ring.

3-(4-Chloro-phen-yl)-1-cyclo-propyl-2-(2-fluoro-phen-yl)-5-phenyl-pentane-1,5-dione.

In the title compound, C26H22ClFO2, the cyclo-propane ring is disordered over two orientations, with site-occupancy factors of 0.64 (2) and 0.36 (2). The major occupancy component of the cyclo-propane ring makes dihedral angles of 47.6 (7), 50.4 (7) and 65.4 (7)° with the fluoro-, chloro- and unsubstituted benzene rings, respectively [the corresponding values for the minor occupancy component are 47.6 (12), 51.0 (12) and 60.9 (12)°]. An intra-molecular C-H⋯O hydrogen bond occurs. The F and Cl atoms deviate by 0.0508 (12) and 0.0592 (7) Šfrom the planes of their attached benzene rings. In the crystal, C-H⋯F hydrogen bonds link the mol-ecules into chains along the b-axis direction.

1,4-Bis(3-chloro-pyrazin-2-yl-oxy)benzene.

In the title compound, C14H8Cl2N4O2, the pyrazine rings are orthogonal to the benzene ring, making dihedral angles of 88.42 (8) and 89.22 (8)°. The Cl atoms attached to the pyrazine rings deviate by -0.0597 (5) and 0.0009 (5) Šfrom the ring plane. The crystal structure features C-H⋯N hydrogen bonds.