A mixture of 3-(3-ethoxy-4-methoxyphenyl)-3-(1-oxoisoindolinyl)propanoic acid (500 mg, 1.41 mmol) and N,N′-carbonyldiimidazole (250 mg, 1.54 mmol) in methylene chloride (30 mL) under nitrogen was stirred at room temperature for 30 minutes. To the solution was added 0-methyl hydroxylamine hydrochloride (175 mg, 2.09 mmol) followed by the addition of 1-methyl piperidine (0.26 mL, 2.14 mmol). The mixture was stirred at room temperature for 2 hours and then was heated to reflux for 14 hours. The cooled reaction mixture was washed with hydrochloric acid (1N, 25 mL), saturated sodium bicarbonate (25 mL), brine (25 mL), and then dried over sodium carbonate and sodium sulfate. Removal of solvent in vacuo gave a solid which was stirred with ether (10 mL) for 30 minutes. This suspension was filtered and the solid was washed with ether (2×10 mL) to give 3-(3-ethoxy-4-methoxyphenyl)-N-methoxy-3-(1-oxoisoindolinyl)-propionamide as a white solid (360 mg, 67% yield): mp, 138.0–139.5° C.; 1H NMR (CDCl3) δ 1.41 (t, J=6.9 Hz, 3H, CH3), 2.95 (dd, J=4.6, 14.5 Hz, 1H, CHH), 3.53 (dd, J=11.2, 14.5 Hz, 1H, CHH), 3.62 (s, 3H, CH3), 3.84 (s, 3H, CH3), 4.02 (q, J=6.9 Hz, 2H, CH2), 4.23 (d, J=17.1 Hz, 1H, NCHH), 4.46 (d, J=17 Hz, 1H, NCHH), 5.49 (dd, J=4.4, 10.3 Hz, 1H, NCH), 6.78–6.99 (m, 3H, Ar,), 7.27–7.51 (m, 3H, Ar), 7.78 (dd, J=7.4 Hz, 1H, Ar), 10.08 (br s, 1H, NH); 13C NMR (CDCl3) δ 14.66, 37.52, 49.48, 54.94, 5.91, 64.01, 64.41, 111.37, 112.12, 119.26, 122.75, 123.54, 128.04, 131.38, 131.68, 132.58, 141.44, 148.56, 149.15, 167.81, 169.47. Anal. Calcd for C21H24N2O5: C, 65.61; H, 6.29; N, 7.29. Found: C, 65.23; H, 6.52; N, 6.88.
