10α-Hy-droxy-13-{[4-(4-meth-oxy-phen-yl)piperazin-1-yl]meth-yl}-4,9-dimethyl-3,8,15-trioxatetra-cyclo-[10.3.0.0.0]penta-decan-14-one.

The title compound, C(26)H(36)N(2)O(6), was synthesized from 9α-hy-droxy-parthenolide (9α-hy-droxy-4,8-dimethyl-12-methylen-3,14-dioxa-tricyclo-[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 fused five- and ten-membered rings with two additional ep-oxy ring systems and a meth-oxy-phenyl-piperazine 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 hy-droxy group forming the flap. The mol-ecular conformation is determined by an O-H⋯N hydrogen bond between the hy-droxy group and a piperazine N atom. The crystal structure is built up by weak C-H⋯O inter-actions.