C(=O)([O-])[O-].[K+].[K+].[CH3:7][C:8]1[NH:9][CH:10]=[CH:11][N:12]=1.Br[CH2:14][C:15]([O:17][CH2:18][CH3:19])=[O:16]>O1CCCC1>[NH3:9].[CH3:7][C:8]1[N:9]([CH2:14][C:15]([O:17][CH2:18][CH3:19])=[O:16])[CH:10]=[CH:11][N:12]=1Potassium carbonate (8.42 g, 61 mmol) was added to a solution of 2-methylimidazole (5 g, 61 mmol) in tetrahydrofuran (100 mL) and the suspension was stirred for 30 minutes. Ethyl bromoacetate (6.75 mL, 61 mmol) was added and the reaction was stirred for a further 30 minutes at room temperature. The mixture was filtered, washing through with dichloromethane:methanol (90:10). The filtrate was evaporated under reduced pressure and the crude product was purified by column chromatography on silica gel using dichloromethane:methanol:0.88 ammonia (93:7:0.5) as eluant to afford the title compound as an oil, 5.28 g.
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