Reaction Steps
1,8-Diazabicyclo[5,4,0]-undec-7-ene (0.8 g, 5.3 mmol) was added to a stirred suspension of 3-(4-aminomethyl-1-oxo-1,3-dihydro-isoindol-2-yl)-piperidine-2,6-dione hydrochloride (0.7 g, 2.1 mmol) in acetonitrile (100 mL). The mixture was stirred for 30 minutes. n-Butyryl chloride (0.3 g, 3.2 mmol) was added, and the mixture was stirred at room temperature overnight. The mixture was concentrated, and the residue was stirred with CH2Cl2 (60 mL) and 2NHCl (30 mL). Solid was collected and slurried with ethanol (20 mL) to give N-[2-(2,6-dioxo-piperidin-3-yl)-1-oxo-2,3-dihydro-1H-isoindol-4-ylmethyl]-butyramide (0.5 g, 67%) as a white solid: mp 244-246° C.; 1H NMR (DMSO-d6) δ 0.85 (t, J=7.4 Hz, 3H, CH3), 1.40-1.60 (m, 2H), 1.99-2.14 (m, 3H), 2.34-2.65 (m, 2H), 2.86-2.98 (m, 1H), 4.32-4.53 (m, 4H), 5.11-5.18 (dd, J=4.9 and 13.2 Hz, 1H, CH), 7.48-7.64 (m, 3H, Ar), 8.13 (t, J=5.1 Hz, 1H, NH), 11.02 (s, 1H, NH); 13C NMR (DMSO-d6) δ 13.67; 18.65, 22.61, 31.19, 37.16, 38.93, 46.15, 51.54, 121.62, 128.29, 130.60, 131.63, 134.82, 140.08, 168.08, 171.02, 172.01, 172.88; Anal. calcd. for C18H21N3O4: C, 62.96; H, 6.16; N, 12.24. Found: C, 63.08; H, 6.06; N, 12.08.
