反应详情

A solution of lithium hydroxide (78 mg, 3.7 mmol) in water (6 ml) was added to a solution of 5-(trifluoromethyl)benzofuran-2-carboxylic acid ethyl ester (705 mg, 2.73 mmol) in 1,4-dioxane (6 ml). 1,4-Dioxane was added until a clear solution was obtained. The reaction mixture was stirred for 16 h at room temperature. It was diluted with an 1 N aqueous solution of sodium hydroxide and washed with tert-butyl methyl ether (2×30 ml). The aqueous solution was acidified with a 10% aqueous solution of sodium hydrogen sulphate until pH 3 was obtained. It was extracted with ethyl acetate (3×40 ml). The combined ethyl acetate layers were dried over magnesium sulphate. The solvent was removed in vacuo to give crude 5-(trifluoromethyl)benzofuran-2-carboxylic acid which was used in the next step without further purification.

1. customwas obtained
2. washwashed with tert-butyl methyl ether (2×30 ml)
3. customwas obtained
4. extractionIt was extracted with ethyl acetate (3×40 ml)
5. dry with materialThe combined ethyl acetate layers were dried over magnesium sulphate
6. customThe solvent was removed in vacuo