CI.[CH3:3][C:4]1[N:8]=[C:7]([CH2:9][C:10](=[O:12])[CH3:11])[O:6][N:5]=1.[C:13](=O)([O-])[O-].[K+].[K+]>C(OCC)(=O)C.CCCCCCC>[CH3:3][C:4]1[N:8]=[C:7]([CH:9]([CH3:13])[C:10](=[O:12])[CH3:11])[O:6][N:5]=1Methyl iodide (0.375 ml, 6 mmol) was added to a mixture of 1-(3-methyl-[1,2,4]oxadiazol-5-yl)-propan-2-one (0.84 g, 6 mmol) and potassium carbonate (4.15 g, 30 mmol) in acetoniotrile (8 mL), and the mixture was stirred at 20° C. for 12 h. Insoluble material was filtered off and the filtrate was diluted with dichloromethane. The solution was washed with 1 N hydrochloric acid and with brine, dried over sodium sulfate, and evaporated under reduced pressure. The residual oil was subjected to column chromatography on silica gel. Heptane/0-20% ethyl acetate eluted successively the title compound 3-methyl-3-(3-methyl-[1,2,4]oxadiazol-5-yl)-butan-2-one (181 mg, 18%), obtained as colorless oil, Rf 0.4 (SiO2, ethyl acetate/heptane 1:1), MS ISP (m/e): 169.1 [(M+H)+]; 3-(3-Methyl-[1,2,4]oxadiazol-5-yl)-butan-2-one (296 mg, 3 2%), obtained as colorless oil, Rf 0.2 (SiO2, ethyl acetate/heptane 1:1), MS ISP (m/e): 155.1 [(M+H)+]; and 3-hydroxy-3-(3-methyl-[1,2,4]oxadiazol-5-yl)-butan-2-one (204 mg, 20%), obtained as colorless oil, Rf 0.1 (SiO2, ethyl acetate/heptane 1:1),
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