Afatinib Impurity E Catalogue A155365 CAS 2223677-62-9 M.W 469.48 M.F C24H25F2N5O3 Specifications FAQs (S,E)-N-(4-((3,4-difluorophenyl)amino)-7-((tetrahydrofuran-3-yl)oxy)quinazolin-6-yl)-4-(dimethylamino)but-2-enamide