反应详情

To a solution of 22 g of methyl-4-bromoacetoacetate in 200 ml benzene is added 14.4 g of 1,1-dimethylbutylurea and 100 mg of p-toluenesulfonic acid. The solution is heated at reflux under nitrogen for 4 hours with water removal. At the end of this period the solution is cooled and concentrated. The residual material is chromatographed on 400 g of silicic acid. Elution with a solution of benzene (60%), ethyl acetate (30%) and methanol (10%) gives crystalline material. Recrystallization of this material from ethyl acetate gives 1.8 g of 1-(1,1-dimethylbutyl)-3-(2,5-dihydro-5-oxo-3-furyl)urea, m.p. 130°-132°C.

1. temperatureThe solution is heated
2. temperatureAt the end of this period the solution is cooled
3. concentrationconcentrated
4. customThe residual material is chromatographed on 400 g of silicic acid
5. washElution with a solution of benzene (60%), ethyl acetate (30%) and methanol (10%)
6. customgives crystalline material
7. customRecrystallization of this material from ethyl acetate