反应详情

A mixture of [rac]-2-ethoxy-3-(4-hydroxy-2-methyl-phenyl)-propionic acid ethyl ester (50 mg, 0.2 mmol), 2-tert-butyl-4-chloromethyl-5-methyl-oxazole (41 mg, 0.22 mmol, example 1, step b]), cesium carbonate (71 mg, 0.22 mmol) and a trace of potassium iodide were suspended in acetone (5 ml). The suspension was heated under reflux for 14 h, the solvent evaporated under reduced pressure and the residue dissolved in 2 N HCl/ice water 1/1 and ethyl acetate. The layers were separated and the aqueous layer was extracted two times with ethyl acetate. The combined organic layers were washed two times with brine and dried over sodium sulfate. The solvent was removed under reduced pressure and the residue purified by column chromatography (silica gel, cyclohexane/AcOEt) to give 50 mg (0.12 mmol, 63%) of the title compound as colorless oil.

1. temperatureThe suspension was heated
2. temperatureunder reflux for 14 h
3. customthe solvent evaporated under reduced pressure
4. dissolutionthe residue dissolved in 2 N HCl/ice water 1/1
5. customThe layers were separated
6. extractionthe aqueous layer was extracted two times with ethyl acetate
7. washThe combined organic layers were washed two times with brine
8. dry with materialdried over sodium sulfate
9. customThe solvent was removed under reduced pressure
10. customthe residue purified by column chromatography (silica gel, cyclohexane/AcOEt)