[CH3:1][C:2]1[CH:3]=[C:4]2[C:8](=[CH:9][CH:10]=1)[C:7](=[O:11])[CH2:6][CH2:5]2.[N+:12]([O-])([O-:14])=[O:13].[K+]>S(=O)(=O)(O)O>[CH3:1][C:2]1[CH:3]=[C:4]2[C:8](=[CH:9][C:10]=1[N+:12]([O-:14])=[O:13])[C:7](=[O:11])[CH2:6][CH2:5]2This step was performed according to the method described in Journal of Medicinal Chemistry, 2006, 49, 7502-7512. 5-Methylindan-1-one (3.27 g, 22.4 mmol) was dissolved in concentrated sulfuric acid (27 ml), a solution of potassium nitrate (2.28 g, 22.6 mmol) in concentrated sulfuric acid (5 ml) was added dropwise over 10 min under ice-cooling with stirring, and the mixture was stirred at the same temperature for 2 hr. The reaction mixture was added to ice water, and extracted with an ethyl acetate-hexane=1:1 mixed solvent. The organic layer was washed with saturated aqueous sodium hydrogen carbonate and saturated brine, and dried over anhydrous magnesium sulfate. The insoluble material was filtered off, and the solution was concentrated under reduced pressure. The obtained oil was purified by silica gel column chromatography (ethyl acetate-hexane) to give the title compound (2.37 g, yield 55%) as a colorless solid.
読み込み中…