Reaction Steps
To a suspension of 3-(4-methylaminomethyl-1-oxo-1,3-dihydro-isoindol-2-yl)-piperidine-2,6-dione hydrochloride (0.60 g, 1.86 mmol) and m-tolyl isocyanate (0.29 mL, 2.23 mmol) in dry CH2Cl2 (80 ml), was added diisopropylethylamine (0.45 mL g, 2.60 mmol). The mixture was stirred at room temperature overnight and a suspension was obtained. The reaction mixture was filtered, and the solid was rinsed with CH2Cl2 and slurred with acetone to give 1-[2-(2,6-dioxo-piperidin-3-yl)-1-oxo-2,3-dihydro-1H-isoindol-4-ylmethyl]-1-methyl-3-m-tolyl-urea as a solid (0.41 g, 52%): mp 208-210° C.; HPLC: Waters Symmetry C-18, 3.9×150 mm, 5 micro, 1 mL/min, 240 nm, 40/60 (CH3CN/H2O): tR=2.57 (99%); 1H NMR (DMSO-d6): δ 1.99-2.08 (m, 1H), 2.24 (s, 3H), 2.28-2.35 (m, 1H), 2.55-2.62 (m, 1H), 2.85-2.92 (m, 1H), 2.96 (s, 2H), 4.36 (d, J=17.3 Hz, 1H), 4.43 (d, J=17.3 Hz, 1H), 4.64 (s, 2H), 5.10-5.17 (dd, J=5.1, 13.2 Hz, 1H), 6.78 (d, J=7.4 Hz, 1H), 7.10 (t, J=7.6 Hz, 1H), 7.29-7.25 (m, 2H), 7.45 (d, J=7.2 Hz, 1H), 7.53 (t, J=7.4 Hz, 1H), 7.63 (d, J=7.3 Hz, 1H), 8.38 (s, 1H). 11.02 (s, 1H). 13C NMR (DMSO-d6) δ: 21.17, 22.56, 31.17, 34.71, 46.25, 48.38, 51.56, 117.15, 120.57, 121.71, 122.63, 128.12, 128.43, 129.87, 131.92, 133.87, 137.31, 140.13, 140.27, 155.62, 168.01, 171.01, 172.84. Anal Calcd for C23H24N4O4+0.1 H2O: C, 65.42; H, 5.78; N, 13.27. Found: C, 65.25; H, 5.50; N, 13.14.
