Tuberostemoamide hemihydrate.

In the crystal structure of the title compound {systematic name: (1'S,2R,2'R,3'S,6'R)-3'-ethyl-4-methyl-5H-5'-oxa-10'-aza-spiro-[furan-2,4'-tricyclo-[8.3.0.0(2,6)]trideca-ne]-5,11'-dione hemihydrate}, C(17)H(23)NO(4)·0.5H(2)O, the asymmetric unit contains two mol-ecules of tuberostemoamide with similar conformations and one water mol-ecule. The tuberostemoamide mol-ecule is composed of one seven-membered ring (A) and three five-membered rings (B, C and D). Ring A exists in a chair conformation, both rings B and C exist in envelope conformations, and ring D is almost planar with a mean deviation of 0.0143 (4) Å in one molecule and 0.0095 (3) Å in the other.. The dihedral angles between the planes of rings C and D are 75.1 (3)° in one mol-ecule and 74.5 (3)° for the other. The solvent water mol-ecule links the tuberostemoamide mol-ecules through O-H⋯O(ketone) hydrogen bonds. Weak C-H⋯O inter-actions are also present, involving both the water mol-ecule and a heterocyclic ether O-atom acceptor.