反应详情

1.1 ml (10 mmol) of methyl acetoacetate in 5 ml of dry tetrahydrofuran are added dropwise under nitrogen to a suspension of 360 mg (12 mmol) of 80% strength sodium hydride in 30 ml of dry tetrahydrofuran at -5° C. After 15 minutes, 6.2 ml (10 mmol) of 15% strength butyllithium in n-hexane are added dropwise at the same temperature and the mixture is subsequently stirred for 15 minutes. 2 g (5 mmol) of the compound from Example 4, dissolved in 20 ml of dry tetrahydrofuran, are subsequently added dropwise and the mixture is subsequently stirred for 30 minutes at -5° C. 3.3 ml of 50% strength acetic acid are cautiously added to the reaction solution, it is diluted with 100 ml of water and the mixture is extracted three times using 100 ml of ether each time. The combined organic phases are washed twice with saturated sodium hydrogen carbonate solution and once with saturated sodium chloride solution, dried over magnesium sulphate and concentrated in vacuo. The residue is chromatographed on a column (silica gel 70-230 mesh, using ethyl acetate/petroleum ether 4:6).

1. additionare subsequently added dropwise
2. stirringthe mixture is subsequently stirred for 30 minutes at -5° C
3. extractionthe mixture is extracted three times
4. washThe combined organic phases are washed twice with saturated sodium hydrogen carbonate solution and once with saturated sodium chloride solution
5. dry with materialdried over magnesium sulphate
6. concentrationconcentrated in vacuo
7. customThe residue is chromatographed on a column (silica gel 70-230 mesh, using ethyl acetate/petroleum ether 4:6)