Reaction Steps
A suspension of 3-(4-aminomethyl-1-oxo-1,3-dihydro-isoindol-2-yl)-piperidine-2,6-dione hydrochloride (0.7 g, 2.1 mmol) and triethylamine (0.3 g, 2.7 mmol) in THF (30 mL) was cooled to 4° C. Phenyl isocyanate (0.3 g, 2.7 mmol) was added, and the mixture was stirred at room temperature for 5 hours. The mixture was concentrated, and the residue was stirred with 1N HCl (30 mL). The solid was collected and slurried with ethanol (10 mL) to give 1-[2-(2,6-dioxo-piperidin-3-yl)-1-oxo-2,3-dihydro-1H-isoindol-4-ylmethyl]-3-phenyl-urea (0.7 g, 89%) as a white solid: mp 328-330° C.; 1H NMR (DMSO-d6) δ 2.00-2.04 (m, 1H), 2.36-2.64 (m, 2H), 2.86-2.98 (m, 1H), 4.37-4.58 (m, 4H, 2CH2), 5.12-5.19 (dd, J=5.0 and 13.2 Hz, 1H, CH), 6.71 (t, J=5.7 Hz, 1H, NH), 6.89 (t, J=7.3 Hz, 1H, Ar), 7.21 (t, J=7.6 Hz, 2H, Ar), 7.38 (d, J=7.6 Hz, 2H, Ar), 7.48-7.65 (m, 3H, Ar), 8.61 (s, 1H, NH), 11.03 (s, 1H, NH); 13C NMR (DMSO-d6) δ 22.57, 31.18, 39.67, 46.20, 51.58, 117.80, 121.20, 121.54, 128.29, 128.62, 130.33, 131.64, 135.59, 139.90, 140.29, 155.22, 168.09, 171.01, 172.84; Anal. calcd. for C21H20N4O4: C, 64.28; H, 5.14; N, 14.28. Found: C, 64.36; H, 4.96; N, 14.17.
