The cyclo-hexene ring that constitutes a part of the tetra-hydroxanthene fused-ring system of the title compound, C(23)H(26)O(4), adopts a flattened half-chair conformation that approximates an envelope conformation (in which the methyl-ene 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...

MCM-41-R-SO3H catalyzed one-pot synthesis of 1,8-dioxo-octahydroxanthenes is reportedunder reflux conditions. The catalyst is easily prepared, highly stable, very simple to handle andrecycled for five times without loss of significant activity