(2E)?-N-?[4-?[(3-?chloro-?4-?fluorophenyl)?amino]?-?7-?[[(3S)?-?tetrahydro-?3-?furanyl]?oxy]?-?6-?quinazolinyl]?-?4-?hydroxy-2-?butenamide is an impurity of Afatinib (A355300), an aminocrotonylamino-substituted quinazoline derivative used for treating cancer and diseases of the respiratory tract, lungs, gastrointestinal tract, bile duct, and gallbladder.
