The title compound, C(19)H(29)NO(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 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. In the crystal, weak C-H⋯O hydrogen bonds connect the mol-ecules into layers parallel to (001). An intra-molecular O-H⋯N hydrogen bond is also present.