(+)-Austrocorticin and austrocorticinic acid, the first anthraquinones derived from a propionate-triggered octaketide

Abstract

The toadstool pigments (1) and (2) bearing a unique C₂ side chain at C-3 in the anthraquinone nucleus have been isolated and characterised and their biogenesis studied by feeding ¹³C labelled precursors to young fruit bodies; high specific incorporation of label from sodium [3-¹³C]propionate into the C-3′ methyl group of (1) indicates a clear propionate ‘starter’ effect is operating.