Reaction of 2-halogeno-4-phenylpyrimidines with potassium amide in liquid ammonia. On the possible occurrence of two SN (ANRORC)-mechanisms

On amination of 2-X-4-phenylpyrimidine (X=F, Cl, 1) with potassium amide in liquid ammonia at −75°. 2-amino-4-phenylpyrimidine is obtained as main product, together with some 3-amino-3-phenylacrylonitrile. It was proved using 2-halogeno-4-phenyl-[1,3-15N]-pyrimidines that the displacement reaction occurs for the greater part via an SN(ANRORC)-mechanism (82% for X=F, 88% for X=Cl and 73% for X=1). It was further found that the 3-amino-3-phenylacrylonitrile, obtained from the 15N-labelled pyrimidines. does not contain15N. This very unexpected result is discussed.