Pterocarpan biosynthesis: 2′-hydroxy-isoflavone and -isoflavanone precursors of demethylhomopterocarpin in red clover

Abstract

2′-Hydroxy-isoflavone (7) and -isoflavanone (8) are excellent precursors of demethylhomopterocarpin (1) but not maackiain (2) in Cu²⁺-treated red clover seedlings; pterocarp-6a-ene (9) is hardly incorporated into the pterocarpans and (1) is not a precursor of (2).