To a mixture of 2-aminobenzamide (1.0 g, 7.35 mmol) and 4-(4-acetylpiperazin-1-yl)benzaldehyde (1.71 g, 7.35 mmol) in DMA (60 mL) was added p-TsOH (0.140 g, 0.73 mmol) and NaHSO3 (0.841 g, 8.1 mmol). The reaction mixture was heated at 150° C. for 21 hours, concentrated to half-volume, diluted with water (300 mL), extracted with CH2Cl2 (2×200 mL), washed with brine (200 mL), dried over anhydrous MgSO4, filtered, and concentrated. The residue was purified by silica gel chromatography, eluting with 100% CH2Cl2 to 100% (92:7:1 CHCl3/MeOH/concentrated NH4OH), to afford 2-(4-(4-acetylpiperazin-1-yl)phenyl)quinazolin-4(3H)-one as a yellow solid (2.27 g, 89%).
