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

The title compound, C(25)H(34)N(2)O(5), 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 mol-ecule contains a fused five- and ten-membered ring system. The ten-membered ring adopts an approximate chair-chair conformation, while the five-membered ring is in an envelope conformation, with the C atom closest to the hy-droxy group forming the flap. The piperazine ring is in a chair conformation. In the crystal, O-H⋯O hydrogen bonds connect mol-ecules into chains along [100]. Weak inter-molecular C-H⋯O hydrogen bonds are also present.