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

The title compound, C(19)H(29)NO(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 is built up from two fused five- and ten-membered rings with the (pyrrolidin-4-yl)methyl group as a substituent. The two five-membered ring display the same envelope conformations, whereas the ten-membered ring adopts an approximate chair-chair conformation. The dihedral angle between the ten-membered ring and the lactone ring is 21.81 (9)°. An intra-molecular O-H⋯N hydrogen bond stabilizes the mol-ecular conformation. In the crystal, inter-molecular C-H⋯O inter-actions link the mol-ecules into chains parallel to the c axis.