Crystal structure of (-)-(5R,7R,8S,9R,10S)-8-methyl-7-[(5 R)-3-methyl-2-oxooxolan-3-en-5-yl]-1-aza-6-oxatricyclo[8.3.0.0 5,9 ]tridecan-13-one monohydrate

The title compound, C₁₇ H₂₃ NO₄ ·H₂ O, is an epimer of the natural tetracyclic alkaloid isosaxorumamide which consists of a fused 5-7-5 tricyclic core and a dihydrofuranone substituent. The terminal dihydrofuran ring is essentially planar with a maximum deviation of 0.0273(14)Å from the mean plane and oxolane, azepane and pyrrolidine rings in the tricyclic ring system adopt twist, twist-chair and envelope forms, respectively. In the crystal, the amide and water molecules are linked by O - H...O hydrogen bonds, forming a tape structure running along the b-axis direction. The tapes are further connected by C - H...O interactions into a three-dimensional architecture.