9-(2-Hydroxy-4,4-dimethyl-6-oxocyclohex-1-en-1-yl)-3,3-dimethyl-2,3,4,9-tetrahydro-1H-xanthen-1-one

Abstract

The cyclohexene ring that constitutes a part of the tetrahydroxanthene fused-ring system of the title compound, C23H26O4, adopts a flattened half-chair conformation that approximates an envelope conformation (in which the methylene C atom bearing the two methyl substituents represents the flap) as five of the six atoms lie approximately on a plane (r.m.s. deviation = 0.020 Å). The mean plane of the cyclohexene ring with the hydroxy substituent is approximately perpendicular to the mean plane of the tetrahydroxanthene system. In the crystal, adjacent molecules are linked by O—H...Ocarbonyl hydrogen bonds into a chain running along the b axis.