AbstractTreatment of solutions of 4,6‐dimethylpyrimidine and 4,6‐di‐t‐butylpyrimidine in acid with aliphatic acids (RCO2H) in the presence of silver nitrate and ammonium peroxydisulfate gave the 2‐R‐4,6‐dimethyl‐ and 2‐R‐4,6‐di‐t‐butylpyrimidines (R = C2H5, i‐C3H7, t‐C4H9). Ths pKa values of these compounds were measured. It was found that 2,4,6‐tri‐t‐butylpyrimidine is a weaker base than expected by about 1.6 pKa units. Oxidation of 2‐isopropyl‐4,6‐di‐t‐butylpyrimidine with permaleic anhydride gives 2‐isopropyl‐4,6‐di‐t‐butylpyrimidine N‐oxide. Under the same conditions 2,4,6‐tri‐t‐butylpyrimidine could not be converted into the corresponding N‐oxide.