Cyanoacetic acid → 6-Amino-1,3-bis(cyclohexylmethyl)uracil

Participants

Reaction Conditions

Reaction Steps

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 67 Pa (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).

Provenance & Evidence