A stirred mixture of 5-amino-5-(3-ethoxy-4-methoxyphenyl)pentan-3-ol hydrochloride(1.15 g, 3.97 mmol), 3-acetamidophthalic anhydride (0.82 g, 3.97 mmol) and triethylamine (0.4 g, 3.97 mmol) in DMF (20 mL) was heated at 80-90° C. for 6 hours. The mixture was then concentrated in vacuo. The residue was dissolved in ethyl acetate (80 mL), washed with water (30 mL), brine (30 mL) and dried over magnesium sulfate. The solvent was removed in vacuo and the residue was purified by chromatography (Silica gel, methylene chloride:ethyl acetate 8:2) to give N-{2-[1-(3-ethoxy-4-methoxyphenyl)-3-hydroxypentyl]-1,3-dioxoisoindolin-4-yl}acetamide (1.35 g, 77%) ; 1H NMR (CDCl3) δ 9.52 (s, 1H), 8.71 (d, J=8.4 Hz, 1H), 7.63 (t, J=7.6 Hz, 1H), 7.48 (d, J=7.3 Hz, 1H), 7.09-7.07 (m, 2H), 6.83-6.80 (m, 1H), 5.61-5.55 (J=3.9, 11.9 Hz, 1H), 4.11 (q, J=6.9 Hz, 2H), 3.84 (s, 3H), 3.47 (m, 1H), 2.97-2.86 (m, 1H), 2.25 (s, 3H), 2.06-1.95 (m, 1H), 1.78 (b, 1H), 1.62-1.52 (m, 2H), 1.45 (t, J=7.0 Hz, 3H), 0.95 (t, J=7.3 Hz, 3H); 13C NMR (CDCl3) δ 170.39, 169.23, 168.11, 148.94, 148.14, 137.32, 135.83, 131.81, 131.19, 124.72, 120.30, 117.94, 115.31, 112.87, 111.09, 70.01, 64.36, 55.86, 51.29, 37.92, 30.46, 24.92, 14.73, 9.90.
