Ring transformations in reactions of heterocyclic halogeno compounds with nucleophiles (XVIII): Pyrimidines (XVIII). D/H exchange studies during the conversion of 2‐substituted 4‐chloropyrimidines into 2‐substituted 4‐methyl‐s‐triazines by treatment with potassium amide in liquid ammonia

Abstract 4‐Chloro derivatives of 2‐piperidino‐ and 2‐morpholinopyrimidine are converted by potassium amide in liquid ammonia into 2‐piperidino‐ and 2‐morpholino‐4‐methyl‐s‐triazine, respectively, in about 80‐85% yield. From the results of the reactions of the 6‐monodeuterio and the 5,6‐dideuterio derivatives of 4‐chloro‐2‐morpholinopyrimidine with the same reagent it has been concluded that during the reaction course an intermediate must be present which contains an acidic hydrogen. An acetylenic intermediate is proposed.