L. Vijayalakshmi

1,5,13‐Tri­methyl‐9‐phenyl‐8,10‐dioxatetra­cyclo[7.7.1.02,7.011,16]­heptadeca‐2,4,6,11,13,15‐hexaene

In the title compound, C24H22O2, both six-membered heterocyclic rings adopt a distorted envelope conformation. The mean planes passing through these rings are nearly perpendicular to each other [dihedral angle 88.39 (7)°].

N-(p-Hydroxybenzylidene)phenylamine N-Oxide

The crystal structure of the title compound, C~3HIIN02, confirms that it exists as a nitrone. The geometry about C~N is Z. The torsion angles O8--N8--C7-- H7 (174.55(2) °) and C8--N8--C7--H7 (-0.89(4) °) indicate the trans and cis positions around the nitrone moiety.

Piperidinium 3-[(4-hydroxy-5,7-di­methyl-2-oxo-2H-chromen-3-yl)­phenyl­methyl]-5,7-di­methyl-2-oxo-2H-chromen-4-olate

In the title salt, C5H12N+*C29H23O6-, both benzopyran systems are planar. Intermolecular N--H...O hydrogen bonds and a short O--H...O intramolecular hydrogen bond are observed in the structure.