According to the procedure given for 210f, 209d (3.93 g, 7.9 mmol) was hydrolyzed with KOH (85%, 4.0 g, 60.6 mmol) in ethanol (60 mL) and water (10 mL) at reflux for 3 h and at room temperature overnight. After the usual workup and drying, 210d (3.0 g, 87%) was obtained as an oil 1H NMR (CDCl3): δ 7.40-7.10 (m, 10H), 2.32 (t, 4H, J=7.2), 2.10-1.80 (m, 4H), 1.60-1.45 (m, 4H), 1.54 (s, 6H), 1.25-1.10 (m, 4H). 13C NMR (CDCl3): δ 211.1, 182.5, 142.8, 128.4, 126.9, 126.0, 49.9, 42.3, 38.7, 24.2, 24.0, 22.3. HRMS (LSIMS, nba): Calcd for C27H35O5 (MH+): 439.2484. found: 439.2497. HPLC: 93.7% pure.
