To a solution of 2-amino-4,6-dimethoxy-benzamide (0.80 g, 4.00 mmol) and 4-(3-hydroxy-propyl)-3,5-dimethyl-benzaldehyde (0.98 g, 5.1 mmol) in N,N-dimethylacetamide (15 mL) were added NaHSO3 (58.5 wt %, 0.80 g, 4.40 mmol) and p-TSA (0.155 g, 0.81 mmol) and the reaction mixture was heated at 115° C. for 16 hours, then cooled to room temperature. N,N-dimethylacetamide was removed under reduced pressure. The residue was diluted with water (50 mL), stirred for 30 minutes, and then filtered and washed with water. The crude compound was purified by column chromatography (silica gel 230-400 mesh; 5% methanol in dichloromethane as eluent) to give 2-[4-(3-hydroxy-propyl)-3,5-dimethyl-phenyl]-5,7-dimethoxy-3H-quinazolin-4-one as an off-white solid. Yield: 1.10 g (73%).
