(1S,2R,3R,6R,7S,8R,10S,11S)-13-{[4-(4-Chloro­phen­yl)piperazin-1-yl]meth­yl}-10-hy­droxy-4,9-dimethyl-3,8,15-trioxatetra­cyclo­[10.3.0.0(2,4).0(7,9)]penta­decan-14-one

The title compound, C(25)H(33)ClN(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 is built up from fused five- and ten-membered rings with two additional ep­oxy ring systems and a chloro­phenyl­piperazine group as a substituent. The ten-membered ring adopts an approximate chair–chair conformation, while the piperazine ring displays a chair conformation and the five-membered ring shows an envelope conformation with the C atom closest to the hy­droxy group forming the flap. The mol­ecular conformation is stabilized by an intra­molecular O—H⋯N hydrogen bond between the hy­droxy group and a piperazine N atom. The crystal structure is stabilized by weak C—H⋯O inter­actions.