Chemistry and crystal structure of leprolomin, a novel diphenyl ether from the lichen Psoroma leprolomum

Abstract

The isolation and structural elucidation of 3'-(2''-acetyl-3''-hydroxy- 5''-methoxy-4''-methylphenoxy)-2',4'-dihydroxy-6'-methoxy-5'- methylacetophenone (leprolomin) (12), an unusual lichen metabolite probably derived biogenetically by C-O phenolic coupling of two units of C-methylphloroacetophenone, is reported. Spectroscopic data on leprolomin and its derivatives allowed the structure to be limited to six possibilities; hence the crystal structure of leprolomin triacetate (15) was determined by X-ray diffraction.