To a mixture of t-butyl 4-(2-((S)-pyrrolidin-3-ylamino)quinazolin-4-yl)piperazine-1-carboxylate (0.30 g), p-chlorophenylacetic acid (0.13 g), and chloroform (5 mL) were added HOBt.H2O (0.18 g) and EDC.HCl (0.18 g), and the mixture was stirred at room temperature for 2 days. To the reaction mixture was added saturated aqueous sodium hydrogencarbonate, and the mixture was extracted with chloroform. The organic layer was dried with anhydrous sodium sulfate, the desiccant was removed by filtration, the filtrate was concentrated under reduced pressure, and the residue was purified by silica gel column chromatography (NH silica gel, hexane/ethyl acetate=3:2) to obtain t-butyl 4-(2-((S)-1-(2-(4-chlorophenyl)ethanoyl)pyrrolidin-3-ylamino)quinazolin-4-yl)piperazine-1-carboxylate (0.29 g). (2) To a solution of t-butyl 4-(2-((S)-1-(2-(4-chlorophenyl)ethanoyl)pyrrolidin-3-ylamino)quinazolin-4-yl)piperazine-1-carboxylate (0.28 g) in methanol (5 mL) was added a solution (1.3 mL) of 4 M HCl in ethyl acetate, and the mixture was stirred overnight. The solvent was evaporated under reduced pressure, and the residue was crystallized in diethyl ether to obtain the title compound (0.15 g).
