Reaction Steps
A stirred solution of 2-amino-N-(2,6-dioxo-piperidin-3-yl)-3-methyl-benzamide (0.9 g, 3.4 mmol) and trimethyl orthoformate (4.5 mL) and p-toluene sulfonic acid (250 mg) in acetonitrile (20 mL) was heated to reflux for 17 hours. To the mixture, was added water (75 mL) and stirred for 20 minutes. The suspension was filtered and washed with methanol (20 mL), water (20 mL) and ethyl acetate (20 mL) to give a purple solid. The solid in NMP (4 mL) was heated at 80° C. for 30 minutes. To the solution, was added water (1 mL), and the mixture was allowed to cool to room temperature. The suspension was filtered and washed with water (30 mL) to give 3-(8-methyl-4-oxo-4H-quinazolin-3-yl)-piperidine-2,6-dione as a light purple solid (660 mg, 72% yield): HPLC: Waters Symmetry C18, 5 μm, 3.9×150 mm, 1 mL/min. 240 nm, 30/70 CH3CN/0.1% H3PO4, 3.07 min (98.6%); mp: 290-292° C.; 1H NMR (DMSO-d6) δ 2.11-2.19 (m, 1H, CHH), 2.56 (5, 3H, CH3), 2.62-2.93 (m, 3H, CH2, CHH), 5.48 (br, 1H, NCH), 7.46 (t, J=8 Hz, 1H, Ar), 7.73 (d, J=8 Hz, 1H, Ar), 7.99 (d, J=8 Hz, 1H, Ar), 8.38 (s, 1H, CH), 11.16 (s, 1H, NH); 13C NMR (DMSO-d6) δ 17.01, 22.53, 30.97, 56.22, 121.36, 123.79, 126.51, 126.86, 135.03, 135.47, 136.39, 145.96, 146.36, 159.97, 169.92, 172.52; LCMS: MH=272; Anal Calcd for C14H13N3O3: C, 61.99; H, 4.83; N, 15.49. Found: C, 61.70; H, 4.68; N, 15.40.
