12-{[4-(4-Bromophenyl)piperazin-1-yl]methyl}-9α-hydroxy-4, 8-dimethyl-3,14-dioxatricyclo[9.3.0.02,4]tetradec-7-en-13-one

Abstract

The title compound, C25H33BrN2O 4, was synthesized from 9α-hydroxyparthenolide (9α-hydroxy-4,8-dimethyl-12-methylen-3,14-dioxa-tricyclo[9.3.0.0 2,4]tetradec-7-en-13-one), which was isolated from the chloroform extract of the aerial parts of Anvillea radiata. The molecule is built up from two fused five-and ten-membered rings with an additional epoxy ring system and a bromophenylpiperazine group as a substituent. The ten-membered ring adopts an approximate chair-chair-chair conformation, while the piperazine ring displays a chair conformation and the five-membered ring shows an envelope conformation with the C atom closest to the hydroxy group forming the flap. An intramolecular O-H..N hydrogen bond stabilizes the molecular conformation. The crystal packing features C-H..O hydrogen bonds, which link the molecules into zigzag chains running along the b-axis direction.