Reaction Steps
A solution of 2-bromo-4-(2,3-dimethyl-naphtho[2,3-b]furan-4-yl)-6-ethyl-phenol (0.30 g, 0.76 mmol), 60% sodium hydride (33 mg, 0.83 mmol), 4-bromobutyric acid, methyl ester (0.44 mL, 3.82 mmol), and anhydrous benzene (1.0 mL) was heated at 100° for 6 h. A second portion of 4-bromobutyric acid methyl ester (0.45 mL, 3.91 mmol) and potassium carbonate (0.5 g, 3.62 mmol) was added and the reaction mixture was heated at 100° for 6 h. The crude reaction mixture was chromatographed with hexane/ethyl acetate to give the title compound as a solid (0.31 g, 82%): NMR (DMSO-d6): δ8.00 (d, J=8 Hz, 1H), 7.98 (s, 1H), 7.48 (d, J=8 Hz, 1H), 7.46 (d, J=2 Hz, 1H), 7.43 (ddd, J=1, 7, 8 Hz, 1H), 7.35 (ddd, J=1, 7, 8 Hz, 1H), 7.26 (d, J=2 Hz, 1H), 4.03 (dd, J=6, 9 Hz, 1H), 3.98 (dd, J=6, 9 Hz, 1H), 3.63 (s, 3H), 2.74 (d of quartets, J=7, 15 Hz, 1H), 2.69 (d of quartets, J=7, 15 Hz, 1H), 2.62 (t, J=7 Hz, 2H), 2.38 (s, 3H), 2.09 (quintet, J=7 Hz, 2H), 1.56 (s, 3H), 1.18 (t, J=7 Hz 3H); MS(EI): [M+], 1 bromine isotope pattern, 494/496.
