Chemical Name: Afatinib Impurity 27
                            
                            Synonym: Phosphonic acid, P-[2-[[4-[(3-chloro-4-fluorophenyl)amino]-7-[[(3S)-tetrahydro-3-furanyl]oxy]-6-quinazolinyl]amino]-2-oxoethyl]-, diethyl ester; Diethyl P-[2-[[4-[(3-chloro-4-fluorophenyl)amino]-7-[[(3S)-tetrahydro-3-furanyl]oxy]-6-quinazolinyl]amino]-2-oxoethyl]phosphonate; Phosphonic acid, [2-[[4-[(3-chloro-4-fluorophenyl)amino]-7-[[(3S)-tetrahydro-3-furanyl]oxy]-6-quinazolinyl]amino]-2-oxoethyl]-, diethyl ester; (S)-Diethyl 2-(4-(3-chloro-4-fluorophenylamino)-7-(tetrahydrofuran-3-yloxy)quinazolin-6-ylamino)-2-oxoethylphosphonate