Facile Aza-Michael Additions of Uracil Derivatives to Acrylates

24 Aza-Michael adducts were synthesised in moderate to excellent yields by the addition of 5-substituted uracils to acrylates with ethylamine as a catalyst. Many of the adducts were obtained in almost quantitive yield without column chromatography. The procedure provideded an efficient approach to the synthesis of N-1 uracil adducts using acrylates as acceptors. The structures of the compounds were determined by 1H NMR, 13C NMR, mass spectra and X-ray crystallography analyses. The uracil unit is present in DNA and related natural products and has a broad spectrum of biological activity.