In a SUS autoclave were placed 420 mg (1.00 mmol) of t-butyl [3-(2-chloro-6,7-dimethoxyquinazolin-4-yl)phenyl]carbamate, tetrahydrofuran (2.5 mL), and 2-propanol (1.25 mL), to this mixture was added a methanol solution (2.5 mL) of 40% methylamine, and the mixture was stirred at 90° C. for 8 hours. The reaction mixture was allowed to cool and then poured into a mixed solution of ethyl acetate (40 mL), tetrahydrofuran (40 mL), and 5% w/w sodium chloride solution (50 mL) to extract the organic layer. The organic layer was washed with 5% w/w sodium chloride solution (50 mL) and then concentrated under reduced pressure. To the concentration residue was added t-butyl methyl ether (2.1 mL), and the mixture was crystallized with a spatula and then stirred at room temperature for 3 hours. The precipitated crystals were collected by filtration and dried to give 348 mg of a target product (yield: 83.8%).
