organic compounds
Open access
The title compound, C28H24O5, consists of a fused tricyclic system containing two five-membered rings and one six-membered ring. The five-membered rings both exhibit an envelope conformation with the O atom at the flap, whereas the six-membered ring adopts a boat conformation. The dihedral angle between the 4-methylphenyl rings at the 1,8-positions is 76.4 (1)°. In the crystal, molecules are stacked in columns along the a axis through C—HO interactions.
organic compounds
Open access
There are two independent molecules (A and B) in the asymmetric unit of the title compound, C14H12ClNO3. The mean planes of the methyl ester unit (Cmethyl—O—C=O; r.m.s. deviation = 0.051 Å for molecule A and 0.016 Å for molecule B) and the chloroquilonine ring system (r.m.s. deviation = 0.023 Å for molecule A and 0.014 Å for molecule B) form dihedral angles of 63.5 (1)° in molecule A and 78.1 (1)° in molecule B. The main difference between the two independent molecules is reflected in the (H)O—C—C=C(H2) torsion angle which is −109.7 (2)° in molecule A and 10.6 (2)° in molecule B. An intramolecular O—HO hydrogen bond is observed in molecule A. In the crystal, molecules A and B are linked into pairs via bifurcated O—H(N,Cl) hydrogen bonds and a weak C—HO hydrogen bond links pairs of molecules into chains along [100].