Brusatol

The title compound, C₂₆H₃₂O₁₁, is composed of an α,β-unsaturated cyclo­hexa­none ring (A), two cyclo­hexane rings (B and C), a six-membered lactone ring (D) and tetra­hydro­furan ring (E). Ring A exists in a half-chair conformation with a C atom displaced by 0.679 (2) Å from the mean plane through the remaining five atoms. Ring B exists in a normal chair conformation. Both rings C and D exist in a twisted-chair conformation due to the O-atom bridge and the carbonyl group in rings C and D, respectively. Ring E shows an envelope conformation with a C atom displaced by 0.761 (1) Å from the mean plane through the remaining five atoms. The ring junctions are A/B trans, B/C trans, C/D cis and D/E cis. An intra­molecular O—H...O hydrogen bond occurs. In the crystal, O—H...O hydrogen bonds involving the hy­droxy, lactone and ester groups and C—H...O inter­actions are observed.

14,15-Didehydro­hellebrigenin

The title compound, C₂₄H₃₀O₅, is the didehydro product of the steroid hellebrigenin (systematic name: 3β,5,14-trihy­droxy-19-oxo-5β-bufa-20,22-dienolide). It consists of three cyclo­hexane rings (A, B and C), a five-membered ring (D) and a six-membered lactone ring (E). The stereochemistry of the ring junctions are A/B cis, B/C trans and C/D cis. Cyclo­hexane rings A, B and C have normal chair conformations. The five-membered ring D with the C=C bond adopts an envelope conformation. Lactone ring E is essentially planar with a mean derivation of 0.006 (4) Å and is β-oriented at the C atom of ring D to which it is attached. There is an O—H...O hydrogen bond in the mol­ecule involving the hy­droxy groups. In the crystal, O—H...O hydrogen bonds link the mol­ecules into chains propagating along [010]. The chains are linked by C—H...O contacts into a three-dimensional network.