Boron tribromide → 3-[4-(5-Hydroxy-2-methyl-phenoxy)-2-methyl-phenyl]-propionic acid ethyl ester

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Reaction Steps

The compound of 3-[4-(5-Methoxy-2-methyl-phenoxy)-2-methyl-phenyl]-propionic acid ethyl ester (1.02 g, 3.10 mmol) is dissolved in DCM (15 mL) under nitrogen at −78° C., and BBr3 (1M, CH2Cl2) (4.64 mL, 4.64 mmol) is added. The mixture is stirred at that temperature for 10 minutes and the bath is removed. The mixture is stirred at rt for 2 h, and water is added. The mixture is neutralized to pH=7 with NaOH (10%). The mixture is extracted with DCM. The organic layer is dried with Na2SO4 and filtered, and then the solvent is evaporated in vacuo. Purification by flash chromatography by eluting with hexane:ethyl acetate 5:1 to afford the title compound (0.48 g, 50%). Rf=0.13 (hexane:ethyl acetate 5:1). 1H NMR (300 MHz, CDCl3): δ1.26 (t, 3H, J=7.3 Hz), 2.16 (s, 3H), 2.26 (s, 3H), 2.57 (t, 2H, J=7.3 Hz), 2.89 (t, 2H, J=7.5 Hz), 4.15 (q, 2H, J=7.3 Hz), 6.44 (d, 1H, J=2.4 Hz), 6.58 (dd, 1H, J=2.4, 8.1 Hz), 6.68 (dd, 1H, J=2.4, 8.3 Hz), 6.75 (d, 1H, J=2.2 Hz), 6.92 (s, 1H), 7.04 (t, 2H, J=8.1 Hz).

Provenance & Evidence