Depsidone synthesis. VII. Vicanicin and norvicanicin

Abstract

The lichen Psoroma sphinctrinurn (Mont.) Nyl. occurs in two or more chemical strains. 2,7-Dichloro- 3 - hydroxy -8-methoxy- 1,4,6,9 - tetramethyl - 11H- dibenzo[b,e][l,4]dioxepin- 11-one (vicanicin) (2), a known depsidone, is a metabolite of one strain, and 2,7-dichloro-3,8-dihydroxy-1,4,6,9-tetramethyl-1lH-dibenzo[b,e][1,4]dioxepin-11-one (norvicanicin) (3) is shown to be a metabolite of another. By oxidative coupling of an appropriate benzophenone (7) and subsequent steps both of these metabolites were synthesized.