反应详情

N,N-Di-n-butylurea (34.45 g, 0.2 mmol), cyanoacetic acid (19.56 g, 0.23 mol), and acetic anhydride (81.66 ml, 0.8 mol) were heated at 80° C. for 2 h under nitrogen and solvent was removed by rotary evaporation to yield N-(2-cyanoacetyl)-N,N'-dibutylurea. The N-(2-cyanoacetyl)-N,N'-dibutylurea was dissolved in methanol (100 ml) and 4N NaOH (100 ml) was added. The reaction mixture was cooled for 30 min with stirring and the solid was filtered and dried to yield 1,3-di-n-butyl-6-aminouracil (47.04 g, 99.5%) as a colorless solid, m.p. 90.1°-92.4° C.; 1H NMR (DMSO-d6) δ1.72-1.93 (m, 6H, 2×CH3, 1.18-1.33 (m, 4H, 2×CH2), 1.39-1.52 (M, 4H, 2×CH2), 3.70 (t, 2H, N--CH2), 3.76 (t, 2H, N--CH2), 4.64 (s, 1H, H-4), 6.77 (br s, exchangeable with D2O, 2H, NH2).

1. temperatureThe reaction mixture was cooled for 30 min
2. filtrationthe solid was filtered
3. customdried