The reaction of 2-thiobarbituric acid (I) with ethyl bromoacetate (II) by means of NaHCO3 in ethanol - water gives ethyl-(4,6-dihydroxy-2-pyrimidinylthio)acetate (III), which by halogenation with POCl3 and N,N-diethylaniline yields ethyl (4,6-dichloro-2-pyrimidinylthio)acetate (IV). The condensation of (IV) with 2,3-dimethylaniline (V) by means of Na2CO3 in refluxing ethanol affords ethyl [4-chloro-6-(2,3-xylidino)-2-pyrimidinylthio]acetate (VI), which is finally hydrolyzed with Na2CO3 in refluxing ethanol. Description.- Crystals, m.p. 146-51 C; Na salt, m.p. 183 C (decomp.).