Abstract: A series of 1-aryl substituted dihydro-, 5-methyldihydro-and 6-methyl-dihydro-2, 4 (1 H, 3 H) pyrimidinediones and their 2-thio analogues were obtained by reaction of the corresponding β-alanines or α-methyl-and β-methyl-β-alanines with urea or potassium thiocyanate. The reaction of N-(2, 3-and 3, 5-dimethylphenyl)-α-methyl-β-alanines with ethyl acetoacetate gave 1-(2, 3-or 3, 5-dimethylphenyl)-2, 5-dimethyl-1, 4, 5, 6-tetrahydro-4 (1 H ...
