New Dibenzofurans and Depsides From the Lichen Bunodophoron patagonicum

Abstract

The lichen Bunodophoron patagonicum has been shown to contain five new dibenzo -furans: ascomatic acid (3,7-dimethoxy-1,9-dimethyldibenzofuran-2-carboxylic acid) (2) and the corresponding methyl ester (3); 7-O-methylnorascomatic acid (3-hydroxy-7-methoxy-1,9-dimethyldibenzofuran-2-carboxylic acid) (4) and the corresponding methyl ester (5); and norascomatic acid (3,7-dihydroxy-1,9-dimethyldibenzofuran-2-carboxylic acid) (6). The lichen also contains two new depsides : patagonic acid [2-hydroxy-4-(2′-hydroxy-4′-methoxy-6′-methyl-benzoyloxy)-6-(2′-oxononyl)benzoic acid] (10) and isopatagonic acid [2-hydroxy-4-(2′-hydroxy-4′-methoxy-6′-(2′-oxononyl) benzoyloxy )-6-methylbenzoic acid] (11). The structure of all new natural products was confirmed by total synthesis.