反应详情

To a stirred solution of sodium ethoxide (prepared from 2.55 g of sodium, 10 mmol) in ethanol (60 ml), was added diethyl tert-butylmalonate (20 g, 92 mmol). The mixture was heated up to reflux. Urea (5.83 g, 97 mmol) in hot ethanol (50 ml) was added and the mixture was refluxed for 6 hr. The mixture was then evaporated in vacuo and the residue was dissolved in water (80 ml). The solution was washed with ether and the water layer was cooled in an ice bath and acidified by the addition of conc. hydrochloric acid. The precipitate was filtered, washed with cold water and n-hexane, and dried in vacuo to give 8.22 g (48%) of a white solid. m.p. 247-248° C.; 1H NMR (200 MHz, DMSO-d6) δ 1.00 (9H, s), 2.83 (1H, s), 11.11 (2H, s).

1. temperatureThe mixture was heated up
2. temperatureto reflux
3. temperaturethe mixture was refluxed for 6 hr
4. customThe mixture was then evaporated in vacuo
5. dissolutionthe residue was dissolved in water (80 ml)
6. washThe solution was washed with ether
7. temperaturethe water layer was cooled in an ice bath
8. additionacidified by the addition of conc. hydrochloric acid
9. filtrationThe precipitate was filtered
10. washwashed with cold water and n-hexane
11. customdried in vacuo