Synthesis
A mixture of N'-[2-cyano-4,5-bis(2-methoxyethoxy)phenyl]-N,N-dimethyl-formamidine (compound of Formula II) 60g, with m-aminophenylacetylene (compound of Formula III) 30g, and acetic acid 300mL, was heated with stirring at a temperature of 95~105 for 20~40min; cooled down to 85~90, and dropwise added 4:1 volume ratio of tert-butanol/water mixed solvent 60mL, stirring the reaction under heat preservation for 25min; the reaction was completed, cooled to room temperature, and the reaction solution was concentrated under reduced pressure to obtain about 91g of the crude product containing the target (formula I); using column chromatography, the eluent was dichloromethane/methanol=60:1 (v/v), and the formula I compounds in the crude product were subjected to column chromatography to obtain an isolate of about 4.1g. HPLC The purity was 96.2%. About 4.1 g of the above isolate was added to the mixed solvent of isopropanol and ethyl acetate, isopropanol: ethyl acetate=4:1 (v/v), heated to reflux, all dissolved and then filtered while hot, and the filtrate was left to precipitate crystals for 7~8h at -5~0C, dried, to obtain a high purity of erlotinib impurity of about 3.7 g. The purity of HPLC was 99.30%.
