Reaction Steps
A mixture of 4-(aminomethyl)-2-[1-(3-ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]isoindoline-1,3-dione (0.34 g, 0.79 mmol) and 2,5-dimethoxytetrahydrofuran (0.10 g, 0.79 mmol) in acetic acid (5 mL) was heated to reflux for 1 hour. The reaction mixture was then concentrated in vacuo and the residue was stirred with ethyl acetate (50 mL) and saturated sodium bicarbonate (25 mL). The organic layer was washed with water (25 mL), brine (25 mL), dried and concentrated. The residue was purified by flash chromatography (methylene chloride:ethyl acetate, 95:5) to afford 2-[1-(3-ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]-4-(pyrrolylmethyl)isoindoline-1,3-dione (0.23 g, 60% yield): mp 80-82° C.; 1H NMR (CDCl3) δ 7.71 (d, J=7.3 Hz, 1H, Ar), 7.57 (t, J=7.7 Hz, 1H, Ar), 7.26 (m, 2H, Ar), 7.15 (d, J=7.0 Hz, 2H, Ar), 6.96 (d, J=7.8 Hz, 1H, Ar), 6.71 (d, J=1.7 Hz, 1H, Ar), 6.22 (d, J=1.8 Hz, 1H, Ar), 5.94-5.88 (dd, J=4.4 and 10.3 Hz, 1H, NCH), 5.57 (s, 2H, CH2), 4.63-4.53 (dd, J=10.7, 14.4 Hz, 1H, CHH), 4.13 (q, J=7.0 Hz, 2H, CH2), 3.85 (s, 3H, CH3), 3.80-3.72 (dd, J=4.4, 14.4 Hz, 1H, CHH), 2.86 (s, 3H, CH3), 1.47 (t, J=6.9 Hz, 3H, CH3); 13C NMR (CDCl3) δ 168.08, 167.69, 149.72, 148.63, 138.71, 134.74, 132.65, 131.86, 129.44, 126.92, 122.69, 121.46, 120.47, 112.49, 111.44, 109.15, 64.51, 55.95, 54.65, 48.73, 48.57, 41.58, 14.69; Anal. Calcd for C25H26N2O6S: C, 62.23; H, 5.43; N, 5.81; S, 6.64. Found: C, 62.25; H, 5.56; N, 5.63; S, 6.83.
