2-Methyl-4-amino-6-hydroxypyrimidine (I) submits to the Mannich reaction in acid medium with formaldehyde and piperidine, dimethylamine, or dethylamine and forms 5-piperidinomethyl (IIa), 5-dimethylaminomethyl (IIb), or 5-diethyl-aminomethyl (IIc) compound. (I) also submits to the Mannich reaction even with formaldehyde and methylamine to form the 5-methylaminomethyl derivative (IId) though the yield is poor compared to the use of secondary amines. 2-Methyl-4, 6-dihydroxypyrimidine (VI) also forms the 5-piperidinomethyl derivative (VII) by reaction with formaldehyde and piperidine but the yield is also poor in this case. 2-Methyl-4-amino-5-aminomethylpyrimidine (VIII) was obtained by heating the methiodide of 2-methyl-4-amino-5-dimethylaminomethylpyrimidine (Vb), derived from (IIb), in conc. ammonia water.