Crystal structure of (E)-13-{4-[(Z)-2-cyano-2-(3,4,5-tri-meth-oxy-phen-yl)ethen-yl]phen-yl}parthenolide methanol hemisolvate.

The title compound, C33H35NO6 [systematic name: (Z)-3-(4-{(E)-[(E)-1a,5-dimethyl-9-oxo-2,3,7,7a-tetra-hydro-oxireno[2',3':9,10]cyclo-deca-[1,2-b]furan-8(1aH,6H,9H,10aH,10bH)-yl-idene]meth-yl}phen-yl)-2-(3,4,5-tri-meth-oxy-phen-yl)acrylo-ni-trile methanol hemisolvate], C33H35NO6·0.5CH3OH, was prepared by the reaction of (Z)-3-(4-iodo-phen-yl)-2-(3,4,5-tri-meth-oxy-phen-yl)acrylo-nitrile with parthenolide [systematic name: (E)-1a,5-dimethyl-8-methyl-ene-2,3,6,7,7a,8,10a,10b-octa-hy-dro-oxireno[2',3':9,10]cyclo-deca-[1,2-b]furan-9(1aH)-one] under Heck reaction conditions. The mol-ecule is built up from fused ten-, five- (lactone) and three-membered (epoxide) rings with a {4-[(Z)-2-cyano-2-(3,4,5-tri-meth-oxy-phen-yl)ethen-yl]phen-yl}methyl-idene group as a substituent. The 4-[(Z)-2-cyano-2-(3,4,5-tri-meth-oxy-phen-yl)ethen-yl]phenyl group on the parthenolide exocyclic double bond is oriented in a trans position to the lactone ring to form the E isomer. The dihedral angle between the benzene ring of the phenyl moiety and the lactone ring mean plane is 21.93 (4)°.