Peroxidative conversion of hemigossypol to gossypol. A revised structure for isohemigossypol

Abstract

Phytoalexins from Gossypium have been identified as hemigossypol (2,3,8-trihydroxy-4-isopropyl-6-methyl-l-naphthaldehyde) and isohemigossypol (2,7,8-trihydroxy-4-isopropyl-6-methyl-l-naphthaldehyde) in separate reports, but comparisons of their u.v.-visible, ¹H n.m.r. and mass spectra indicate that they are the same; double resonance studies of the phytoalexin now indicate that the correct structure is hemigossypol, which has been confirmed by dimerization of the phytoalexin to gossypol with the enzyme peroxidase.