There are numerous natural and synthetic products that possess a indane ring system showing significant biological activity, including simple natural compounds such as the asarone dimer a component of the essential oil of Acarus calamus 1 or complex compounds, such as pallidol a resveratrol dimer from Cissus pallida. 2 In addition, there are many synthetic compounds possessing the indane skeleton that show significant biological activity, for example, indinavir ® and ...