A new tetrahydrodibenzofuran and other constituents from the lichen Usnea antarctica

A new tetrahydrodibenzofuran, 2,6-diacetyl-3,4a, 7,9-tetrahydroxy-8,9b-dimethyl-1-oxo-1,4,4a, 9b-tetrahydrodibenzofuran, together with seven known compounds were isolated from the lichen Usnea antarctica. Their structures were elucidated on the basis of spectroscopic methods and by comparison with literature values.