Lithium hydroxide, monohydrate → 5-bromo-3-(methylcarbamoyl)-6-(N-methylmethylsulfonamido)benzofuran-2-carboxylic acid

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Reaction Steps

To a suspension of methyl 5-bromo-3-(methylcarbamoyl)-6-(N-methylmethylsulfonamido)benzofuran-2-carboxylate (2.90 g, 6.92 mmol) in 1,4-dioxane/H2O (30 mL/5 mL) was added LiOH.H2O (870 mg, 20.75 mmol). The mixture was stirred at room temperature overnight. Then it was concentrated in vacuo, diluted with water, acidized with HCl (aq. 2 M) and extracted with EtOAc. The organic layer was washed with brine, dried over Na2SO4 and concentrated give the product of 5-bromo-3-(methylcarbamoyl)-6-(N-methylmethylsulfonamido)benzofuran-2-carboxylic acid (2.50 g, yield: 89%). It was used for the next step without further purification. 1H-NMR (DMSO-d6, 400 MHz) δ 9.16 (br s, 1H), 8.27 (s, 1H), 8.16 (s, 1H), 3.17 (s., 6H), 2.82 (d, J=4.4 Hz, 3H). (M+H)+: 405/407.

Provenance & Evidence