3-(4-溴-2,6-二甲基苯基)咪唑烷-2,4-二酮

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: Ethyl isocyanatoacetate (581 mg, 4.50 mmol) and N,N-diisopropylethylamine (426 mg, 1.65 mmol) were added to a solution of 4-bromo-2,6-dimethylaniline (600 mg, 3.00 mmol) in toluene (6 ml) with stirring in a nitrogen stream, and the mixture was heated with stirring at 120° C. After 30 minutes, the reaction solution was brought to room temperature, and the precipitate was collected by filtration, washed with toluene and then dried under reduced pressure. The resulting solid was suspended in toluene (6 ml). DBU (68.4 mg, 2.25 mmol) was added and the mixture was heated with stirring at 120° C. After 30 minutes, the reaction solution was brought to room temperature and diluted with ethyl acetate, and the organic layer was washed with a 1 N aqueous hydrochloric acid solution and saturated brine. The organic layer was dried over anhydrous magnesium sulfate, and the magnesium sulfate was then removed by filtration. The filtrate was concentrated under reduced pressure. The residue was subjected to column chromatography (hexane-ethyl acetate) to give 3-(4-bromo-2,6-dimethyl-phenyl)-imidazolidine-2,4-dione (570 mg, 67%). the mixture was heated with stirring at 120° C was brought to room temperature the precipitate was collected by filtration washed with toluene dried under reduced pressure the mixture was heated with stirring at 120° C After 30 minutes was brought to room temperature the organic layer was washed with a 1 N aqueous hydrochloric acid solution and saturated brine The organic layer was dried over anhydrous magnesium sulfate the magnesium sulfate was then removed by filtration The filtrate was concentrated under reduced pressure