2-Methylsulfanyl-6-Polyfluoroalkyl-Pyrimidin-4-Ones: Synthesis and Nucleophilic Substitution Reactions

We have optimized the reaction conditions for the synthesis of 2-methylsulfanyl-6-polyfluoro-alkylpyrimidin-4-ones. In particular the yield of trifluoromethyl-substituted heterocycle was increased to 96%, and new polyfluoroalkyl-substituted analogs were prepared. The interaction of these heterocycles with morpholine or hydrazine was shown to result in nucleophilic substitution of the methylsulfanyl group, leading to 2-morpholino- and 2-hydrazino-6-polyfluoroalkylpyrimidin-4-ones. The reaction of 2-(2-phenylhydrazino)-6-trifluoromethylpyrimidin-4-one with paraform produced 5-oxo-2-phenyl-7-tri-fluoromethyl-5H-1,2,4-triazolo[4,3-а]pyrimidin-1-id-2-ium. The lactam structure of the synthesized heterocycles was established by X-ray structural analysis, as well as by IR and NMR spectroscopy.