反应详情

A solution of compound (42) 750 mg in dry tetrahydrofuran 7 ml was cooled at −70° C. and n-BuLi (1.56 mol/l hexane solution) 2.2 ml was added dropwise to the solution. The mixture was stirred for 1 h. Dimethylformamide 257 μl was added and the mixture was stirred for 2 h. The reaction mixtures was diluted with an aqueous ammonium chloride solution and extracted with ethyl acetate. The extracts were washed with brine, dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The residue obtained was chromatographed on aluminum oxide in ethyl acetate:hexane (1:4) to give the titled compound as yellow oil, 556 mg. This was recrystallized from hexane to give the titled compound as colorless crystals, m.p. 104-106° C., 395 mg. Yield 59%

1. stirringthe mixture was stirred for 2 h
2. customThe reaction mixtures
3. extractionextracted with ethyl acetate
4. washThe extracts were washed with brine
5. dry with materialdried over anhydrous magnesium sulfate
6. concentrationconcentrated under reduced pressure
7. customThe residue obtained
8. customwas chromatographed on aluminum oxide in ethyl acetate:hexane (1:4)