The synthesis of six new barbituric acids 1b, 3a, 4b, 5, and 6b, including the novel 5-hydroxy derivative 3b, is reported together with spectroscopic data (proton magnetic resonance, ultraviolet, and infrared) for these and for five related known barbiturates for which such data is lacking. An interesting occurrence of non-equivalence of the N-1 and N-3 CH2(Et) protons in 3b is discussed.