Neotricone and Norperistictic Acid, Two New Depsidones from the Lichen Genus Phaeographis

Abstract

Two new β-orcinol depsidones, neotricone (4,10-dihydroxy-5,8-dimethyl-3,7-dioxo-1,3-dihydro-7H-isobenzofuro[4,5-b][1,4]benzodioxepin-11-carboxylic acid) (2) and norperistictic acid (1,4,10-trihydroxy-5,8-dimethyl-3,7-dioxo-1,3-dihydro-7H-isobenzofuro[4,5-b][1,4]benzodioxepin-11-carboxylic acid) (4) have been identified in the lichens Phaeographis syngraphizans and P. neotricosa. The structure of the new depsidones followed from a combination of partial syntheses, chromatographic comparisons, and spectroscopic data.