Perfluoroalkylation of 2-Thiopyrimidine Derivatives

Abstract

The method of perfluoroalkylation of heterocyclic thiols and disulfides by thermolytic reaction with xenon(II) bisperfluoroalkylcarboxylates has been extended to sulfur-containing pyrimidines, including 2-mercaptopyrimidines, symmetrical disulfides, and S-trifluoroacetyl derivatives obtained from the corresponding thiols. The main reaction products are 2-SC_nF_2n+1 (n = 1, 2)-substituted pyrimidines. Their formation proceeds only via disulfides into which the initial thiols and S-trifluoroacetyl derivatives are converted in the reaction medium. Side reactions occurred in the case of trifluoromethylation linked with the perfluoroalkylation of the pyrimidine nucleus at the free 5 position (in the case of the 4,6-dimethyl derivative), or at position 4 or 4 and 5 (for unsubstituted pyrimidine). In addition, the introduction of the CF₃ group at one of the methyl substituents was confirmed by the formation of CH₂CF₃ fragment.