反应详情

To a mixture of 4-hydroxy-3-methylbenzofuran-2-carboxylic acid (1.12 g, 6 mmole), ethyl chloroformate (1.01 ml, 13.2 mmole), and methylene chloride (20 ml) stirred at 0°-5° C. under argon was added triethylamine (1.82 ml, 13.2 mmole) in methylene chloride (6 ml) dropwise over 5 minutes. The mixture was stirred for 15 minutes and then aniline (1.11 mg, 12 mmole) was added followed by the dropwise addition of triethylamine (1.82 ml, 13.2 mmole) in methylene chloride (3 ml). After 30 minutes, the reaction mixture was washed with water, dried with MgSO4 and evaporated to dryness. The crude product was purified by column chromatography (70 g of Merck silica gel eluted with 1:1:3 ethyl acetate/methylene chloride/hexane to yield 1.38 g (68.1%) of product.

1. stirringThe mixture was stirred for 15 minutes
2. washthe reaction mixture was washed with water
3. dry with materialdried with MgSO4
4. customevaporated to dryness
5. customThe crude product was purified by column chromatography (70 g of Merck silica gel
6. washeluted with 1:1:3 ethyl acetate/methylene chloride/hexane