Crystal structure of limonoid TS3, isolated from .

The title limonoid compound, CHO·0.5HO () [systematic name: (3a,3b,4a,5a,6,7a,8a,8b,11a)-6-(furan-3-yl)-3a,5a,8b,11a-tetra-methyl-3a,4a,5,5a,6,7,7a,8b,11,11a-deca-hydro-oxireno[2',3':4b,5]oxireno[2'',3'':2',3']cyclo-penta-[1',2':7,8]phenanthro[10,1-]furan-3(3a)-one hemihydrate], crystallizes with two independent mol-ecules (1 and 2) in the asymmetric unit and one water mol-ecule. is composed of three six-membered rings (, and ), three five-membered rings (, and ) and two epoxide rings. A group of five fused rings (-) is bonded to a furan ring () with a C-C bond [1.500 (3) Å in mol-ecule 1 and 1.499 (3) Å in mol-ecule 2]. The absolute structures of the mol-ecules in the crystal were determined by resonant scattering; Flack parameter = 0.05 (5). In the crystal, the individual mol-ecules stack in columns along the -axis direction. The water mol-ecule bridges mol-ecules 1 and 2 O-H⋯O and C-H⋯O hydrogen bonds. Together with further C-H⋯O hydrogen bonds, linking mol-ecules 1 and 2, the columns are linked to form slabs parallel to the plane. Within each column, mol-ecules are also linked C-H⋯π inter-actions involving the five-membered furan () rings.