PYRIMIDINE REACTIONS .19. AMINOLYSIS AND HYDROLYSIS OF SULPHOXIDES AND SULPHONES DERIVED FROM 2(PARA-SUBSTITUTED PHENYLTHIO)-PYRIMIDINES

The oxidation of a series of 2-(p-substituted phenylthio)pyrimidines by m-chloroperbenzoic acid yields the corresponding sulphoxides and sulphones. These undergo alkaline hydrolysis to 2-hydroxypyrimidine and aminolysis to 2-pentylaminopyrimidine at rates dependent on the electronic nature of the p-substituent. Hammett plots for the hydrolyses are rectilinear, with the p-nitro-derivatives reacting most rapidly. Similar quantitative treatment of the aminolyses is precluded by base catalysis. 1H N.m.r. and u.v. spectra are used to confirm structures and to follow displacements.