(Z)-6-Hy-droxy-1a,5-dimethyl-8-[(morpholin-4-yl)meth-yl]-2,3,6,7,7a,8,10a,10b-octa-hydro-oxireno[2',3':9,10]cyclo-deca-[1,2-b]furan-9(1aH)-one.

The title compound, C(19)H(29)NO(5), was synthesized from 9α-hy-droxy-parthenolide (9α-hy-droxy-4,8-dimethyl-12-methylen-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 (morpholin-4-yl)methyl group as a substituent. The five-membered lactone ring has an envelope conformation, whereas the ten-membered and the morpholine rings display approximate chair-chair and chair conformations, respectively. The dihedral angle between the ten-membered ring and the lactone ring is 27.93 (6)°. The crystal structure is stabilized by weak inter-molecular C-H⋯O hydrogen-bond inter-actions. An intra-molecular O-H⋯N hydrogen bond also occurs.