A mixture of 2-[1-(3-ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]-4-aminoisoindoline-1,3-dione (570 mg, 1.4 mmol) and cyclopropane carbonyl chloride (2 mL) was heated to reflux for 15 minutes. To the mixture was added methanol (20 mL) and water (5 mL) at room temperature and kept for 30 minutes. The solvent was removed in vacuo to give an oil. The oil was stirred in ether/hexane (15 mL each) for 1 hour to give a suspension. The suspension was filtered and washed with ether to give a yellow solid. The solid was then stirred in ethanol (10 mL) overnight. The suspension was filtered and washed with ethanol to give cyclopropyl-N-{2-[1-(3-ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]-1,3-dioxoisoindolin-4-yl}carboxamide as a yellow solid (380 mg, 57.4% yield); mp, 153-155° C.; 1H NMR (CDCl3) δ0.92-0.99 (m, 2H, 2CHH), 1.11-1.17 (m, 2H, 2CHH), 1.48 (t, J=6.9 Hz, 3H, CH3), 1.61-1.71 (m, 1H, CH), 2.88 (s, 3H, CH3), 3.75 (dd, J=4.4, 14.3 Hz, 1H, CHH), 3.86 (s, 3H, CH3), 4.12 (q, J=7.1 Hz, 2H, CH2), 4.57 (dd, J=10.4, 14.3 Hz, 1H, CHH), 5.89 (dd, J=4.4, 10.3 Hz, 1H, NCH), 6.84-6.88 (m, 1H, Ar), 7.11-7.15 (m, 2H, Ar), 7.48 (d, J=7.2 Hz, 1H, Ar), 7.65 (t, J=7.4 Hz, 1H, Ar), 8.76 (d, J=8.5 Hz, 1H, Ar), 9.69 (s, 1H, NH); 13C NMR (CDCl3) δ8.71, 14.62, 16.16, 41.58, 48.59, 54.60, 55.89, 64.50, 111.49, 112.44, 114.83, 117.91, 120.26, 124.99, 129.27, 130.99, 136.02, 137.77, 148.63, 149.76, 167.49, 169.52, 172.79; Anal Calcd for C24H26N2O7S: C, 59.25; H, 5.39; N, 5.76. Found: C, 59.06; H, 5.30; N, 5.69.
