12-Anilinomethyl-9α-hy-droxy-4,8-dimethyl-3,14-dioxatricyclo-[9.3.0.0]tetra-dec-7-en-13-one.

The title compound, C(21)H(27)NO(4), was synthesized from 9α-hy-droxy-parthenolide, which was isolated from the chloro-form extract of the aerial parts of Anvillea radiata. The asymmetric unit contains two independent mol-ecules. In each, the ten-membered ring displays an approximative chair-chair conformation. Each of the five-membered rings adopts a flattened envelope conformation, the C(H)-C-C(H) atoms representing the flap lie out of the mean plane through the remaining four atoms by 0.443 (2) and 0.553 (2) Å. The dihedral angle between the least-squares planes through the ten- and five-membered rings in the two mol-ecules are similar [22.54 (17) and 23.39 (14)°]. In the crystal, mol-ecules are linked by O-H⋯O, O-H⋯N and N-H⋯O hydrogen bonds.