Investigations into the cine‐Amination of 4‐Substituted‐5‐bromopyrimidines by potassium amide in liquid ammonia

Abstract The cine‐amination of some 4‐R‐5‐bromopyrimidines ( t ‐butyl, phenyl, methoxyl, piperidine, methyl, methylamino, anilino, amino) by potassium amide in liquid ammonia has been studied. Evidence is presented that the conversion into the corresponding 4‐substituted‐6‐aminopyrimidines can proceed in part via an S N (ANRORC) mechanism, involving an open‐chain intermediate, provided that the substituent at C‐4 does not contain an acidic proton in the α‐position to the pyrimidine ring. 5‐Bromo‐4‐piperidinopyrimidine yields the tele ‐amination product, 2‐amino‐4‐piperidinopyrimidine, alongside the 6‐amino derivative. It is proven that the tele ‐amination does not proceed via an S N (ANRORC) mechanism.