Extractives of Australian timbers. XVII. The isolation, structure and synthesis of koparin (7,2',3'-Trihydroxy-4'-methoxyisoflavone)

Abstract

The isolation of koparin, a minor constituent of the wood of Castanospermum australe, is described. By a combination of chemical and spectroscopic methods koparin was shown to be either 7,3?,4?-tri- hydroxy-2?-methoxyisoflavone (5) or 7,2?,3?-trihydroxy-4?- methoxyisoflavone (6). The latter compound has been synthesized by demethylenation of 7-hydroxy-4?-methoxy-2?,3?-methylenedioxyiso- flavone (9) and is identical with koparin.