A compound having one atom as the only common member of two rings.
| Member | Definition | Role |
|---|
| 2,2'-spirobi[3,6,7,8-tetrahydro-1H-cyclopenta[g]naphthalene]-5,5'-dione | A spiro compound that consists of two units of 1,2,3,6,7,8-hexahydro-5H-cyclopenta[b]naphthalen-5-one fused together at position 2. It is an inhibitor of Hepatitis C virus E2 protein that exhibits inhibitory activity against hepatitis C virus infections. | 2,2'-spirobi[3,6,7,8-tetrahydro-1H-cyclopenta[g]naphthalene]-5,5'-dione |
| 5',7'-dimethylspiro[cyclohexane-1,3'-pyrimido[5,4-c][1,2,5]oxadiazine]-6',8'-dione | | 5',7'-dimethylspiro[cyclohexane-1,3'-pyrimido[5,4-c][1,2,5]oxadiazine]-6',8'-dione |
| ainsliadimer a | A sesquiterpene lactone isolated from the whole plants of Ainsliaea macrocephala; exhibits inhibitory activity against production of nitric oxide (NO). | ainsliadimer A |
| crambescidin 800 | An organic heteropentacyclic guanidine alkaloid isolated from the marine sponge Crambe crambe and Batzella. It exhibits anti-HIV-1 and anti-HSV-1 activity. | crambescidin 800 |
| megestrol acetate | A sesquiterpene lactone with formula C15H20O8. It is a neurotoxic natural product found in plants of the family Illiciaceae. | anisatin |
| solavetivone | A cyclic ketone derived from spiro[4.5]dec-6-en-8-one by substitution of hydrogens by methyl groups at positions 6 and 10, and by an isopropenyl group at position 2 (the (2R,5S,10R)-diastereoisomer). | solavetivone |