[C:1]1(=O)[CH2:6][CH2:5][CH2:4][C:3](=[O:7])[CH2:2]1.[C:9]([NH:13][C:14]([NH2:16])=[O:15])([CH3:12])([CH3:11])[CH3:10].O>C1C=CC=CC=1.C1(C)C=CC(S(O)(=O)=O)=CC=1>[C:9]([NH:13][C:14]([NH:16][C:1]1[CH2:6][CH2:5][CH2:4][C:3](=[O:7])[CH:2]=1)=[O:15])([CH3:12])([CH3:11])[CH3:10]To a solution of 11.2 g of 1,3-cyclohexanedione in 250 ml of benzene is added 11.6 g tert-butylurea and 100 mg of p-toluenesulfonic acid. The solution is heated at reflux under nitrogen with water removal for three hours. At the end of this period the solution is cooled and the precipitated product removed by filtration. The precipitate is recrystallized from acetonitrile to give 14 g of 1-tert-butyl-3-(3-oxo-1-cyclohexene-1-yl)urea, m.p. 223°-225° C.
Loading…
