12-{[4-(4-Bromophenyl)piperazin-1-yl]methyl}-9α-hydroxy-4,8-dimethyl-3,14-dioxatricyclo[9.3.0.02,4]tetradec-7-en-13-one

The title compound, C25H33BrN2O4, was synthesized from 9α-hydroxyparthenolide (9α-hydroxy-4,8-dimethyl-12-methylen-3,14-dioxa-tricyclo[9.3.0.02,4]tetradec-7-en-13-one), which was isolated from the chloroform extract of the aerial parts ofAnvillea radiata. The molecule is built up from two fused five- and ten-membered rings with an additional epoxy ring system and a bromophenylpiperazine 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 hydroxy group forming the flap. An intramolecular O—H...N hydrogen bond stabilizes the molecular conformation. The crystal packing features C—H...O hydrogen bonds, which link the molecules into zigzag chains running along theb-axis direction.