12-{[4-(4-Bromo-phen-yl)piperazin-1-yl]meth-yl}-9α-hy-droxy-4,8-dimethyl-3,14-dioxatri-cyclo-[9.3.0.0(2,4)]tetra-dec-7-en-13-one.

The title compound, C25H33BrN2O4, was synthesized from 9α-hy-droxy-parthenolide (9α-hy-droxy-4,8-dimethyl-12-methylen-3,14-dioxa-tri-cyclo-[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 mol-ecule is built up from two fused five- and ten-membered rings with an additional ep-oxy ring system and a bromo-phenyl-piperazine group as a substituent. The ten-membered ring adopts an approximate chair-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 hy-droxy group forming the flap. An intra-molecular O-H⋯N hydrogen bond stabilizes the mol-ecular conformation. The crystal packing features C-H⋯O hydrogen bonds, which link the mol-ecules into zigzag chains running along the b-axis direction.