optically inactive 9-(3,4-dimethoxy-phenyl)-6,7-dimethoxy-3a,4,9,9a-tetrahydro-3H-naphtho[2,3-c]furan-1-one

4-(3,4-dimethoxyphenyl)-6,7-dimethoxybenzo[f][2]benzofuran-1,3-dione

dimethyl 1-(3,4-dimethoxyphenyl)-6,7-dimethoxynaphthalene-2,3-dicarboxylate