(S)-Ethyl 2-((4-((3-chloro-4-fluorophenyl)amino)-7-((tetrahydrofuran-3-yl)oxy)quinazolin-6-yl)amino)-2-oxoacetate (Afatinib Impurity)

(S)-Ethyl 2-((4-((3-chloro-4-fluorophenyl)amino)-7-((tetrahydrofuran-3-yl)oxy)quinazolin-6-yl)amino)-2-oxoacetate (Afatinib Impurity)