10α-Hy-droxy-13-{[4-(2-hy-droxy-phen-yl)piperazin-1-yl]meth-yl}-4,9-dimethyl-3,8,15-trioxatetra-cyclo-[10.3.0.0(2,4).0(7,9)]penta-decan-14-one.

The title compound, C(25)H(34)N(2)O(6), was synthesized from 9α-hy-droxy-parthenolide (9α-hy-droxy-4,8-dimethyl-12-methyl-ene-3,14-dioxatricyclo-[9.3.0.0(2,4)]tetra-dec-7-en-13-one), which was isolated from the chloro-form extract of the aerial parts of Anvillea radiata. The ten-membered ring adopts an approximate chair-chair conformation, while the piperazine ring displays a near regular chair conformation and the five-membered ring an envelope conformation with the C atom closest to the hy-droxy group forming the flap. The mol-ecular conformation is stabilized by an O-H⋯N hydrogen bond, which generates an S(7) loop, and the crystal structure features weak C-H⋯O inter-actions.