Reaction Steps
To a stirred mixture of 2-amino-3,5-dichlorobenzoic acid (5.0 g, 24 mmol) and imidazole (1.9 g, 28 mmol) in acetonitrile (60 mL), was added acetyl chloride (2.0 mL, 28 mmol) at room temperature. The mixture was stirred at room temperature overnight. To the mixture, was added 3-amino-piperidine-2,6-dione hydrogen chloride (3.9 g, 24 mmol), imidazole (3.5 g, 52 mmol) and triphenyl phosphite (6.8 mL, 26 mmol) and heated to reflux for 22 hours. The suspension was filtered and washed with acetonitrile (30 mL), water (2×30 mL), and ethyl acetate (30 mL) to give 3-(6,8-dichloro-2-methyl-4-oxo-4H-quinazolin-3-yl)-piperidine-2,6-dione as a white solid (4.65 g, 58% yield): HPLC: Waters Symmetry C18, 5 μm, 3.9×150 mm, 1 mL/min, 240 nm, 40/60 CH3CN/0.1% H3PO4, 4.78 min (100%); mp: 238-240° C.; 1H NMR (DMSO-d6) δ 2.15-2.22 (m, 1H, CHH), 2.55-2.69 (m, 5H, CH, 2CHH), 2.78-2.91 (m, 1H, CHH), 5.33 (dd, J=6, 11 Hz, 1H, NCH), 7.96 (d, J=2 Hz, 1H. Ar), 8.15 (d, J=2 Hz, 1H, Ar), 11.09 (s, 1H, NH); 13C NMR (DMSO-d6) δ 20.63, 23.85, 30.54, 56.92, 122.55, 24.24, 130.51, 131.72, 134.38, 142.25, 156.80, 159.07, 169.12, 172.53; LCMS: MH=340, 342; Anal Calcd for C14H11N3O3Cl2: C, 49.43; H, 3.26; N, 12.35; Cl, 20.84. Found: C, 49.21; H, 3.11; N, 12.30; Cl, 19.43.
