反应详情

温度

80 °C

Cyanoacetic acid (Aldrich, 21.0 g) was dissolved in acetic anhydride (260 ml). This solution was added to 1,3-bis(cyclohexylmethyl)urea (from step (a), 54.5 g) and the solution maintained at 80° C. for 2 h under nitrogen. Volatiles were removed in vacuo and the residual oil dried by evaporation of portions of 10% water-ethanol (3×400 ml). The residual solids were dissolved in ethanol (600 ml)-water(300 ml) at 80° C. with adjustment of the pH to 10 by addition of 10% aqueous sodium carbonate. The hot solution was diluted with water (75 ml) and cooled to ambient temperature. The colorless crystals which formed were filtered off, washed with water (3×500 ml) and dried at 0.5 Torr to give 6-amino-1,3-bis(cyclohexylmethyl)uracil (64.98 g, 94%), m.p. 138–141° C.; 1H-NMR (DMSO-d6) δ: 6.73 (br s, 2, NH2), 4.63 (s, 1, H-5), 3.67 (d, J=7.3 Hz, 2, NCH2), 3.57 (d, J=7.3 Hz, 2, NCH2), 1.55 and 1.09 (both m, 22, 2 cyclohexyl).

1. customVolatiles were removed in vacuo
2. dry with materialthe residual oil dried by evaporation of portions of 10% water-ethanol (3×400 ml)
3. dissolutionThe residual solids were dissolved in ethanol (600 ml)-water(300 ml) at 80° C. with adjustment of the pH to 10
4. additionby addition of 10% aqueous sodium carbonate
5. additionThe hot solution was diluted with water (75 ml)
6. temperaturecooled to ambient temperature
7. customThe colorless crystals which formed
8. filtrationwere filtered off
9. washwashed with water (3×500 ml)
10. customdried at 0.5 Torr