1,1'-ethane-1,1-diylbis(3,4-dimethoxybenzene) InChI=1/C18H22O4/c1-12(13-6-8-15(19-2)17(10-13)21-4)14-7-9-16(20-3)18(11-14)22-5/h6-12H,1-5H benzene, 1,1'-ethylidenebis[3,4-dimethoxy-