反应详情

Coumarin-3-carboxylic acid (25.0 g, 131 mmol) is dissolved into 100 mL of 4-hydroxy-2-butanone with ˜0.050 g of para-toluene sulfonic acid in a round bottom flask equipped with a stir bar and condenser packed with molecular sieves. The pressure is reduced to ˜15 mmHg and the system is refluxed for 10 hours. The solvents are removed by rotary evaporation. The solid organic residue is purified by column chromatography using 3:1 ethyl acetate:hexanes to yield 2-oxo-2H-chromene-3-carboxylic acid 3-oxo-butyl ester.

1. customequipped with a stir bar and condenser
2. temperaturethe system is refluxed for 10 hours
3. customThe solvents are removed by rotary evaporation
4. customThe solid organic residue is purified by column chromatography