Polyolefinic 18-methyl-19-oxoicosenoic acid pigments from the fungus Piptoporus australiensis(Wakefield) Cunningham

Abstract

Three pigments present in the bright orange fruiting body of the basidiomycete Piptoporus australiensis are identified as (all-E)-18-methyl-19-oxoicosa-2,5,7,9,11,13,15,17-octaenoic acid (piptoporic acid)(4), its methyl ester (3), and (all-E)-(3R)-3-acetoxy-18-methyl-19-oxoicosa-5,7,9,11,13,15,17-heptaenoic acid (5). The absolute configuration of the last named metabolite is established by chemical correlation with methyl (3R)-3-acetoxy-4-carboxybutanoate.