(E)-13-(4-Amino-phen-yl)parthenolide.
The title compound, C21H25NO3 [systematic name: (3aS,9aR,10aR,10bS,E)-3-[(E)-4-(4-amino-benzyl-idene)-6,9a-dimethyl-3a,4,5,8,9,9a,10a,10b-octa-hydro-oxireno[2',3':9,10]cyclo-deca-[1,2-b]furan-2(3H)-one] was obtained from the reaction of parthenolide [synonym: 4,5-ep-oxy-germacra-1(10),11(13)-dieno-12,6-lactone] with 4-iodo-aniline under Heck reaction conditions. It was identified as the E-isomer (conformation about the exocyclic methyl-idene C=C bond; the conformation about the C=C bond in the ten-membered ring is also E). The mol-ecule is built up from fused ten-, five- (lactone) and three-membered (epoxide) rings with a 4-amino-phenyl group as a substituent. The ten-membered ring displays an approximate chair-chair conformation, while the lactone ring has an envelope conformation with the C atom bonded to the ring O atom as the flap. The dihedral angle between the benzene ring of the 4-amino-phenyl moiety and the lactone ring mean plane is 23.50 (8)°. In the crystal, mol-ecules are linked via N-H⋯O hydrogen bonds, between the amine group and the lactone and epoxide ring O atoms, forming chains propagating along the b-axis direction. Adjacent chains are linked via C-H⋯O inter-actions, forming an undulating two-dimensional network lying parallel to the plane (001). The absolute structure of the mol-ecule in the crystal was confirmed by resonance scattering [Flack parameter = 0.03 (3)].
Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
Narsimha Reddy
NR
Penthala
Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
Venumadhav
V
Janganati
Department of Chemistry, University of Kentucky, Lexington, KY 40506, USA.
Sean
S
Parkin
College of Medicine, Department of Physiology & Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
Kottayil I
KI
Varughese
Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
Peter A
PA
Crooks