Reaction Steps
1,8-Diazabicyclo[5.4.0]undec-7-ene (0.4 g, 2.4 mmol) was added to a stirred suspension of 4-aminomethyl-2-(2,6-dioxo-piperidin-3-yl)-isoindole-1,3-dione hydrochloride (0.7 g, 2.0 mmol) in acetonitrile (50 mL). After stirring for 30 minutes, pyridin-2-yl-carbamic acid 2,5-dioxo-pyrrolidin-1-yl ester (0.7 g, 3.0 mmol) was added, and the mixture was stirred at room temperature overnight. The solid was collected and slurried with hot acetone (20 mL) to give 1-[2-(2,6-dioxo-piperidin-3-yl)-1,3-dioxo-2,3-dihydro-1H-isoindol-4-ylmethyl]-3-pyridin-2-yl-urea (0.5 g, 64%) as a white solid: mp>260° C.; 1H NMR (DMSO-d6) δ 2.05-2.09 (m, 1H), 2.49-2.65 (m, 2H), 2.84-2.79 (m, 1H), 4.83 (d, J=6.1 Hz, 2H), 5.14-5.21 (dd, J=5.5 and 12.7 Hz, 1H), 6.91-6.96 (m, 1H), 7.33 (d, J=8.5 Hz, 1H), 7.64-7.88 (m, 4H), 8.17-8.20 (dd, J=1.3 and 5.0 Hz, 1H), 8.90 (t, J=5.7 Hz, 1H), 9.44 (s, 1H), 11.16 (s, 1H); 13C NMR (DMSO-d6) δ 21.96, 30.92, 38.67, 48.85, 93.31, 111.57, 116.91, 121.90, 127.20, 131.67, 133.43, 134.80, 138.23, 139.82, 146.69, 153.27, 154.93, 166.97, 167.49, 169.81, 172.75; Anal. calcd. for C20H17N5O5: C, 58.97; H, 4.21; N, 17.19. Found: C, 58.69; H, 4.10; N, 17.05.
