Sodium Hydroxide → 2-Thiophenecarboxylic acid, 4-bromo-3-methoxy-

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Reaction Steps

The product from Step A above (22.5 g, 84.36 mmol) was dissolved in 60 mL of tetrahydrofuran and added with 125 mL of a 1.0 M NaOH aqueous solution. The mixture was stirred at room temperature for 4 d, then washed with ether (60 mL×2), acidified to pH ˜2 using a 1.0 M HCl aqueous solution. Solids were precipitated out after acidification, and collected by filtration. The solid was dissolved in methylene chloride-ethyl acetate (˜4:1, v/v). The organic solution was washed with H2O and brine, dried with Na2SO4, and concentrated in vacuo to a light yellow solid, further dried on height vacuum, yielding 17.95 g of 4-bromo-3-methoxy-2-thiophene carboxylic acid (90%, MH+=237.0).

Provenance & Evidence