反应详情

A solution of EXAMPLE 20B (2.0 g, 11 mmol), 1,2-ethanediol (1.0 g, 16 mmol) and p-toluenesulfonic acid monohydrate (10 mg) in benzene (10 mL) was heated under reflux with a Dean-Stark apparatus for about 6 hours. After cooling, the mixture was partitioned between ethyl acetate and brine and the organic phase washed with 10% sodium hydroxide solution and water. After concentration, the residue was purified by flash chromatography using 1:5 ethyl acetate/hexane to give the title compound (2.1 g, 80%). MS (DCI): m/z 227 (M+H)+.

1. temperatureunder reflux with a Dean-Stark apparatus for about 6 hours
2. temperatureAfter cooling
3. customthe mixture was partitioned between ethyl acetate and brine
4. washthe organic phase washed with 10% sodium hydroxide solution and water
5. concentrationAfter concentration
6. customthe residue was purified by flash chromatography