Ethanol → 3-Isopropoxy-5-(2-thiophen-3-yl-ethoxy)-benzoic acid

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Reaction Steps

To a solution of 3-isopropoxy-5-(2-thiophen-3-yl-ethoxy)-benzoic acid methyl ester (5.24 g, 16.4 mmol) in THF (120 mL) was added EtOH (80 mL) and water (40 mL) at rt. Sodium hydroxide solution (1.0 M, 49.1 mL) was added slowly with some external cooling if needed. The mixture was stirred at rt overnight. On the second day organic solvents were removed by evaporation. The residue was partitioned between ether and water. After the ether layer was discarded, the aqueous layer was acidified with HCl (6.0 M, ˜8.2 mL) to pH<1, and extracted with EtOAc (3×). Combined EtOAc layers were washed with brine (1×), dried with anhydrous MgSO4, filtered, and concentrated to give 3-isopropoxy-5-(2-thiophen-3-yl-ethoxy)-benzoic acid (4.54 g, 90%) as a white solid. 1H NMR (300 MHz, CDCl3): δ 7.29 (dd, J=5, 3 Hz, 1H), 7.22-7.24 (m, 2H), 7.09-7.10 (m, 1H), 7.04 (dd, J=5, 1 Hz, 1H), 6.69 (m, 1H), 4.59 (m, 1H), 4.21 (t, J=7 Hz, 2H), 3.14 (t, 0.1=7 Hz, 2H), 1.35 (d, J=6 Hz, 6H).

Provenance & Evidence