The identification of four new meta-depsides in the lichen Ramalina asahinae

Abstract

The four new depsides, 2-O-methylsekikaic acid, 2,4'-di-O-methylnorsekikaic acid, 4'-O-methyl-paludosic acid and 4,4'-di-O- methylcryptochlorophaeic acid, have been prepared by unambiguous syntheses and shown to co-occur with usnic acid and boninic acid in several Ramalina species.