Реакция #679309

Уравнение реакции

Coumarin-3-carboxylic acid

para-toluene sulfonic acid

4-hydroxy-2-butanone

→

2-oxo-2H-chromene-3-carboxylic acid 3-oxo-butyl ester

Условия реакции

Обработка

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

Методика

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.

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