3,5a,9-Trimethyl-8-(2-phenylhydrazin-1-ylidene)-4,5,5a,9b-tetrahydro-3aH,8H-naphtho[1,2-b]furan-2(3H)-one

The title compound, C₂₁H₂₄N₂O₂, is a phenyl hydrazine derivative of the well known anthelminthic agent α-santonin, which is composed of three fused rings (benzodieneone, cyclo­hexane and γ-lactone). The cyclo­hexa­dienone ring adopts a boat conformation, the cyclo­hexane ring is in a chair conformation and the trans-fused γ-lactone ring adopts a C-envelope conformation. In the crystal, mol­ecules are linked by N—H...O and C—H...O hydrogen bonds, forming chains along the a axis.

8-[(2-Hy­droxy­phen­yl)imino]-3,5a,9-trimethyl-3a,4,5,5a,8,9b-hexa­hydro­naphtho­[1,2-b]furan-2(3H)-one

The title compound, C₂₁H₂₃NO₃, is a phenyl­imine derivative of the well known anthelmintic agent α-santonin. The trans-fused cyclo­hexane and γ-lactone rings of the α-santonin ring system adopt chair and envelope conformations, respectively, whereas the hexa­diene ring is approximately planar [maximum deviation = 0.029 (4) Å] and forms a dihedral angle of 62.30 (11)° with the benzene ring. An intra­molecular O—H...N hydrogen bond is observed.

1-(3-Meth­oxy­phen­yl)-2-(phenyl­sulfon­yl)ethan-1-one

In the title compound, C₁₅H₁₄O₄S, the dihedral angle between the benzene and phenyl rings is 88.74 (10)°. In the crystal, mol­ecules are linked into a three-dimensional network by C—H...O hydrogen bonds and π–π stacking inter­actions [centroid–centroid distances = 3.6092 (13)–3.8651 (13) Å].

5-Chloro-2-phenyl-1,3-benzothia­zole

In the structure of the title compound, C₁₃H₈ClNS, the dihedral angle between the benzothia­zole ring system and the phenyl ring is 7.11 (8)°. In the crystal, mol­ecules are arranged parallel to the c axis.

2-(5-Chloro-1,3-benzothia­zol-2-yl)-4-meth­oxy­phenol

In the mol­ecule of the title compound, C₁₄H₁₀ClNO₂S, the dihedral angle between the almost planar benzothia­zole ring system [maximum deviation = 0.005 (2) Å] and the benzene ring is 1.23 (9)°. The conformation of the mol­ecule is stabilized by an intra­molecular O—H...N hydrogen bond, forming an S(6) ring motif. In the crystal, mol­ecules are linked into layers parallel to the ac plane by C—H...O hydrogen bonds and π–π stacking inter­actions [centroid–centroid distance = 3.7365 (12) Å].

6-Methyl-4-oxo-4H-chromene-3-carbaldehyde

In the title compound, C₁₁H₈O₃, the benzopyran-4-one or chromone ring system is almost planar, with a maximum deviation of 0.045 (2) Å. The crystal structure is stablized by π–π inter­actions between the benzene and pyran rings of inversion-related mol­ecules stacked along the b axis, with a centroid–centroid distance of 3.5463 (12) Å

Ethyl (E)-3-(6-methyl-4-oxo-4H-chromen-3-yl)prop-2-enoate

In the title compound, C₁₅H₁₄O₄, the chromone ring system is close to being planar [maximum deviation = 0.015 (2) Å]. The double bond of the ethyl prop-2-enoate chain adopts an E conformation and an intra­molecular C—H...O hydrogen bond generates an S6 ring. In the crystal, inversion dimers linked by pairs of C—H...O hydrogen bonds generate R₂²(14) loops. Weak π–π inter­actions [centroid–centroid distance = 3.8493 (12) Å] also occur.

5-Chloro-2-(3,4,5-trimeth­oxy­phen­yl)-1,3-benzothia­zole

In the title compound, C₁₆H₁₄ClNO₃S, the dihedral angle between the almost-planar benzothia­zole ring system [maximum deviation = 0.012 (3) Å] and the aromatic ring of the trimeth­oxy­phenyl group is 15.56 (6)°. In the crystal, the mol­ecules are arranged into layers parallel to the bc plane, held together only by weak van der Waals forces.

3-(2-Ethyl-2-phenyl­hydrazin-1-yl­idene)indolin-2-one

In the title compound, C₁₆H₁₅N₃O, the dihedral angle between the indole ring system (r.m.s. deviation = 0.020 Å) and the phenyl ring is 14.49 (9)°. The mol­ecular conformation is supported by an intra­molecular C—H...O inter­action, which closes an S(7) ring. In the crystal, inversion dimers linked by pairs of N—H...O hydrogen bonds generate R₂²(8) loops.

N′-(3-Chloro­benzyl­idene)-4-hy­droxy­benzohydrazide

The mol­ecule of the title compound, C₁₄H₁₁ClN₂O₂ adopts an E conformation of the azomethine double bond and the dihedral angle between the benzene rings is 38.96 (13)°. In the crystal, mol­ecules are linked by N—H...O and O—H...O (with the ketone O atom as acceptor) and C—H...O (with the hy­droxy O atom as acceptor) hydrogen bonds, forming a three-dimensional network.