Theoretical and Experimental

R factor = 0.048; wR factor = 0.153; data-to-parameter ratio = 17.6. In the title compound, C25H27NO5, each of the cyclohexenone rings adopts a half-chair conformation, whereas the six-membered pyran ring adopts a flattened boat conformation, with the O and methine C atoms deviating from the plane of the other four atoms. In the crystal, weak C—H O hydrogen bonds link molecules into chains parallel to the c axis. Related literature For the crystal structures of xanthene derivatives studied recently by our group, see: Cha et al. (2012); Lee et al. (2012)