Reaction Steps
A mixture of 3,5-dimethyl-4-hydroxybenzaldehyde (0.600 g, 4.00 mmol), N-(2-bromoethyl)-phthalimide (1.22 g, 4.80 mmol), K2CO3 (0.829 g, 6.00 mmol), Nal (3.00 g, 20.0 mmol) in DMF (40.0 mL) was heated at 80° C. for 2.5 h. The reaction was cooled to room temperature, diluted with EtOAc (200 mL), washed with 1 M NaOH (2×100 mL), 1 M HCl (2×100 mL), brine (75 mL), dried over sodium sulfate, filtered and concentrated under vacuum. The residue was chromatographed on silica gel (40 g, hexanes/EtOAc) to provide the expected ether (0.300 g, 23%) as a yellow solid. A mixture of the above ether (0.293 g, 0.907 mmol), 2-amino-4,6-dimethoxybenzamide (0.178 g, 0.907 mmol), NaHSO3 (94%, 0.100 g, 0.907 mmol), and p-TsOH.H2O (0.0173 g, 0.0907 mmol) in DMA (11.3 mL) was stirred at reflux for 1.5 h then cooled to room temperature. The mixture was diluted with EtOAc (250 mL), washed with saturated aqueous ammonium chloride (3×75 mL) and brine (75 mL), dried over sodium sulfate, filtered and concentrated under vacuum. The residue was chromatographed on silica gel (40 g, CH2Cl2/CH3OH) to provide the expected product (0.075 g, 17%) as a light yellow solid. A mixture of the above compound (0.213 g, 0.426 mmol) and 2 M methylamine in THF (25.0 mL) was stirred at room temperature for 17 h. The volatiles were removed under vacuum and the residue was chromatographed on silica gel to provide compound N1-(2-(4-(5,7-dimethoxy-4-oxo-3,4-dihydroquinazolin-2-yl)-2,6-dimethylphenoxy)ethyl)-N2-methylphthalamide (0.0493 g, 22%) and compound 2-(4-(2-aminoethoxy)-3,5-dimethylphenyl)-5,7-dimethoxyquinazolin-4(3H)-one (0.0360 g, 23%) as white solids. Selected data for N1-(2-(4-(5,7-dimethoxy-4-oxo-3,4-dihydroquinazolin-2-yl)-2,6-dimethylphenoxy)ethyl)-N2-methylphthalamide: 1H NMR (300 MHz, DMSO-d6) δ 11.80 (s, 1H), 8.51 (t, J=5.57 Hz, 1H), 8.18 (q, J=4.57 Hz, 1H), 7.89 (s, 2H), 7.53-7.42 (m, 4H), 6.74 (d, J=2.31 Hz, 1H), 6.52 (d, J=2.29 Hz, 1H), 3.96-3.80 (m, 8H), 3.61 (q, J=5.73 Hz, 2H), 2.71 (d, J=4.62 Hz, 3H), 2.32 (s, 6H); MS (APCI) m/z 531 [M+H]+. Selected data for 2-(4-(2-aminoethoxy)-3,5-dimethylphenyl)-5,7-dimethoxyquinazolin-4(3H)-one: 1H NMR (300 MHz, DMSO-d6) δ 7.90 (s, 2H), 6.74 (d, J=2.31 Hz, 1H), 6.51 (d, J=2.32 Hz, 1H), 3.88 (s, 3H), 3.85 (s, 3H), 3.77 (t, J=5.76 Hz, 2H), 2.91 (t, J=5.75 Hz, 2H), 2.30 (s, 6H); MS (APCI) m/z 370 [M+H]+.
