Lithium hydroxide, monohydrate → 2-Bromo-4-[[[(3-hydroxyphenyl)methyl]amino]carbonyl]benzoic acid

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Reaction Steps

A solution of lithium hydroxide monohydrate (4.41 g, 105.1 mmol) in water (15 mL) was added to a solution of 2-bromo-4-[[[(3-hydroxyphenyl)methyl]amino]carbonyl]benzoic acid, methyl ester (Example 14; 15.30 g, 42.0 mmol) in tetrahydrofuran/methanol (2:1, 21 mL). The solution was stirred at room temperature for 1 h, then it was concentrated to remove tetrahydrofuran and methanol. The remaining aqueous solution was extracted with ethyl acetate (15 mL) and the ethyl acetate extract was discarded. The aqueous layer was acidified with 1 M HCl (75 mL) and extracted with ethyl acetate (2×50 mL). The combined organic layers were washed with brine (15 mL), dried (MgSO4), filtered, and evaporated to give 2-bromo-4-[[[(3-hydroxyphenyl) methyl]amino]carbonyl]benzoic acid (15.1 g, quantitative yield) which was used in the next step without further purification.

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