Potentiation of the estrogenic activity of stilbestrol by spiro (cyclohexane-1,2'-indan)-1',4-dione.

During the investigation of a series of spiro compounds having approximately similar molecular dimensions to naturally occurring estrogens, the novel compound spiro(cyclohexane-1,2'-indan)-1',4-dione was prepared. The pretreatment of mice with this estrogenically inactive compound was found to potentiate the estrogenic activity of stilbestrol.