It has been known that oakmoss (Evernia prunastri (L.) Arch.) contains depsides, which are polyfunctional diaryl derivatives. The most important of these depsides are lecanoric acid, evernic acid, divaricatic acid, barbatic acid, atranorin, monochloroatranorin and thamnolic acid (see Figure 1).
It is generally accepted that these depsides are virtually nonvolatile and odorless. The depsides are converted into volatile monoaryl derivatives during treatment of oakmoss with water and solvents. The depsides can be hydrolyzed with water during a fermentation process, and with hot water or steam, Furthermore the depsides can undergo alcoholysis with ethanol, for example, under formation of polyfunctiond monoaryl ethyl esters.
Various qualitative analyses of the odoriferous fraction of oakmoss have been published. So far only one investigation of the quantitative analysis of oakmoss oil has been found in the literature.
