(9bS)-2,6-diacetyl-7,9-dihydroxy-8,9b-dimethyl-(2H,9bH)-dibenzofuran-1,3-dione 1,3(2H,9bH)-Dibenzofurandione, 2,6-diacetyl-7,9-dihydroxy-8,9b-dimethyl-, (9bS)- 6159-66-6 EINECS 228-181-3 NSC 5889 Usnic acid, (-)-