Reaction Steps
To a stirred mixture of 2-amino-4-methylbenzoic acid (2.0 g, 13 mmol) and imidazole (1.1 g, 16 mmol) in acetonitrile (20 mL), was added acetyl chloride (1.1 mL, 16 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 (2.2 g, 13 mmol), imidazole (2.0 g, 30 mmol) and triphenyl phosphite (4.2 mL, 16 mmol) and heated to reflux for 22 hours. To the mixture, was added water (60 mL). The suspension was filtered and washed with water (2×50 mL), ethyl acetate (2×50 mL), and water (50 mL) to give 3-(2,7-dimethyl-4-oxo-4H-quinazolin-3-yl)-piperidine-2,6-dione as a white solid (2.52 g, 67% yield): HPLC: Waters Symmetry C13, 5 μM, 3.9×150 mm, 1 mL/min. 240 nm, 20/80 CH3CN/0.1% H3PO4, 5.13 min (99.9%); mp: 305° C. (decomp); 1H NMR (DMSO-d6) δ 2.08-2.24 (m, 1H, CHH), 2.45 (s, 3H, CH3), 2.56-2.75 (m, 5H, 2CHH), 2.81-2.91 (m, 1H, CHH), 5.24 (dd, J=6, 11 Hz, 1H, NCH), 7.32 (dd, J=1.8 Hz 1H, Ar), 7.43 (s, 1H, Ar), 7.91 (d, J=8 Hz, 1H, Ar), 11.00 (s, 1H, NH); 13C NMR (DMSO-d6) δ 21.00, 21.35, 23.45, 30.61, 56.43, 117.94, 125.80, 126.10, 127.97, 145.21, 146.98, 154.96, 160.34, 169.56, 172.62; LCMS: MH=286; Anal Calcd for C15H15N3O3: C, 63.15; H, 5.21; N, 14.73. Found: C, 63.14; H, 5.21; N, 14.76.
