Hydrochloric Acid → 3-(2,2-dimethyl4-oxo4H-1,3-benzodioxin-5-yl)-benzoic acid, ethyl ester

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Reaction Steps

To a solution of 2,2-dimethyl-5-trifluoromethanesulfonyloxy-4H-1,3-benzodioxin-4-one (2.0 g, 5.8 mmol), 3-ethoxycarbonylphenylboronic acid (1.34 g, 6.9 mmol) and anhydrous K2CO3 powder (2.61 g, 18.9 mmol) in DMF (30 mL) was added tetrakis(triphenylphosphine)palladium (0.202 g, 0.175 mmol). The mixture was heated at reflux for 2 h. The reaction mixture was allowed to cool to room temperature (“rt”) and 1 N HCl (25 mL) was added. The mixture was extracted with EtOAc (3×25 mL). The combined extracts were washed with water and brine, then dried over MgSO4, filtered, and concentrated. The crude material was purified by flash chromatography (1:15 EtOAc/hexanes) to afford 3-(2,2-dimethyl-4-oxo-4H-1,3-benzodioxin-5-yl)-benzoic acid, ethyl ester (1.2 g, 63%) as a white solid: 1H NMR (CDCl3) 1.39 (t, J=7.1 Hz, 3H), 1.80 (s, 6H), 4.39 (q, J=7.0 Hz, 2H), 7.01 (d, J=8.0 Hz, 2H), 7.47-7.57 (m, 3H), 8.00 (t, J=1.5 Hz, 1H), 8.07 (dt, J=7.5, 1.5 Hz, 1H).

Provenance & Evidence