10α-Hy­droxy-4,9-dimethyl-13-[(4-phenyl­piperazin-1-yl)meth­yl]-3,8,15-trioxatetra­cyclo­[10.3.0.0(2,4).0(7,9)]tetra­decan-14-one

The title compound, C(25)H(34)N(2)O(5), was synthesized from 9α-hy­droxy­parthenolide (9α-hy­droxy-4,8-dimethyl-12-methyl­ene-3,14-dioxatricyclo­[9.3.0.0(2,4)]tetra­dec-7-en-13-one), which was isolated from the chloro­form extract of the aerial parts of Anvillea radiata. The mol­ecule contains a fused five- and ten-membered ring system. The ten-membered ring adopts an approximate chair–chair conformation, while the five-membered ring is in an envelope conformation, with the C atom closest to the hy­droxy group forming the flap. The piperazine ring is in a chair conformation. In the crystal, O—H⋯O hydrogen bonds connect mol­ecules into chains along [100]. Weak inter­molecular C—H⋯O hydrogen bonds are also present.