The structure of robustic acid, a new 4-hydroxy-3-phenylcoumarin
Robustic acid, derived from the roots of Derris robusta, is a 4-hydroxy-3-phenylcoumarin closely related to scandenin and Ionchocarpic acid. Methyl robustate, a 4-methoxy-3-phenylcoumarin, has also been isolated.
α- and β-Isodihydrorobustic acid have been synthesised by unambiguous methods.
The demethylation of dihydrorobustic acid has been investigated and two rearrangement products have been characterised.