13-(Imidazol-1-yl)-11,13-dihydromelampomagnolide B monohydrate

The title compound, C₁₈H₂₄N₂O ₄·H₂O {systematic name: (1aR,7aS,8R,10aS,10bS,E)-5- hydroxymethyl-8-[(1H-imidazol-1-yl)methyl]-1a-methyl-2,3,6,7,7a,8,10a, 10b-octahydrooxireno[2′,3′:9,10]cyclodeca[1,2-b]furan-9(1aH)-one monohydrate}, an imidazole derivative of melampomagnolide B was synthesized under Michael addition conditions. The molecule is built up from fused ten-, five-(lactone) and three-membered (epoxide) rings. The internal double bond of the ten-membered ring identifies it as the cis or 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, O-H⋯N and weak C-H⋯O hydrogen bonds link the molecules (along with water) into sheets parallel to the bc plane.