(E)-13-(2-Bromo­phen­yl)micheliolide

The title compound, C₂₁H₂₃BrO₃ [systematic name: (3E,3aS,6Z,9R,9aS,9bS)-3-(2-bromo­benzyl­idene)-9-hy­droxy-6,9-dimethyl-3,3a,4,5,7,8,9,9a-octa­hydro­azuleno[4,5-b]furan-2(9bH)-one] was prepared by the reaction of 1-bromo-2-iodo­benzene with micheliolide [systematic name: (3aS,R,9aS,9bS,Z)-9-hy­droxy-6,9-dimethyl-3-methyl­ene-3,3a,4,5,7,8,9,9a-octa­hydro­azuleno[4,5-b]furan-2(9bH)-one] under Heck reaction conditions. The title compound exhibits intra­molecular O—H...O hydrogen bonding between the hy­droxy group and the lactone ring O atom, forming a ring of graph-set motif S(6). The 2-bromo­phenyl group is trans to the lactone ring, indicating that this is the E isomer (geometry of the exocyclic C=C bond). The dihedral angle between the benzene ring of the 2-bromo­phenyl moiety and the mean plane of the lactone ring is 51.68 (7)°.

Monosuccinate ester of melampomagnolide B

The title monosuccinate derivative of melampomagnolide B [systematic name: 4-(((1aR,7aS,10aS,10bS,E)-1a-methyl-8-meth­yl­ene-9-oxo-1a,2,3,6,7,7a,8,9,10a,10b-deca­hydro­oxireno[2′,3′:9,10]cyclo­deca­[1,2-b]furan-5-yl)meth­oxy)-4-oxo­butan­oic acid], C₁₉H₂₄O₇, was obtained from the reaction of melampomagnolide B with succinic anhydride under nucleophilic addition reaction conditions. The mol­ecule is built up from fused ten-, five- (lactone) and three-membered (epoxide) rings. The inter­nal double bond in the ten-membered ring has the cis geometry (i.e. it is the E isomer). The lactone ring has an envelope-type conformation, with the (chiral) C atom opposite the lactone O atoms as the flap atom. In the crystal, O—H...O hydrogen bonds link the mol­ecules into chains parallel to the b-axis direction.

2,4-Di­chloro-1-iodo-6-nitro­benzene

In the crystal structure of the title compound, C₆H₂Cl₂INO₂, there are weak C—H...Cl inter­actions and I...O [3.387 (4) Å] close contacts. These inter­actions form sheets in the ac plane, with the closest contact between adjacent planes occurring between inversion-related nitro O atoms [3.025 (8) Å]. The molecule possesses mirror symmetry, with the halogen, N and C atoms all lying in the mirror plane. Hence, the dihedral angle between the benzene ring and the nitro group is 90°.