反应详情

6-Amino-3-(cyclohexylmethyl)-1-propyluracil was prepared by the method of V. Papesh, J. Org. Chem. 1951, 16, 1879-1889. A solution of propyl isocyanate (Aldrich, 10.92 mL, 116.5 mmol) and 2-cyano-N-(cyclohexylmethyl)acetamide (from step (a), 14.00 g, 77.7 mmol) in anhydrous toluene (100 mL) was stirred at reflux (heating mantle) under nitrogen for 24 h. Volatiles were then removed at 20 Torr and 50° C., and the resulting orange oil was chromatographed on silica gel. 1-(2-Cyanoacetyl)-1-cyclohexylmethyl-3-propylurea eluted with hexane/ethyl acetate (5:2) as a yellow oil, which solidified upon standing (2.708 g). Unreacted 2-cyano-N-(cyclohexylmethyl)acetamide eluted with hexane/ethylacetate (1:1) as a white crystalline solid (12.02 g), which was resubmitted to the reaction conditions described above. This process was repeated twice to provide 1-(2-cyanoacetyl)-1-cyclohexylmethyl-3-propylurea (total for the three runs: 7.101 g, 34%), 1H-NMR (DMSO-d6) consistent with structure. Unreacted 2-cyano-N-(cyclohexylmethyl)acetamide was also recovered (7.108 g, 51%).

1. temperatureat reflux
2. temperature(heating mantle) under nitrogen for 24 h
3. customVolatiles were then removed at 20 Torr and 50° C.
4. customthe resulting orange oil was chromatographed on silica gel
5. wash1-(2-Cyanoacetyl)-1-cyclohexylmethyl-3-propylurea eluted with hexane/ethyl acetate (5:2) as a yellow oil, which
6. washUnreacted 2-cyano-N-(cyclohexylmethyl)acetamide eluted with hexane/ethylacetate (1:1) as a white crystalline solid (12.02 g), which
7. customwas resubmitted to the reaction conditions