It is purified by conversion to the MgCl2 complex in a small volume of H2O. The complex (~ 5g) is dissolved in the minimum volume of hot H2O, passed through a column of activated Al2O3 (200g), and the column is washed with EtOH. Evaporation of the EtOH gives a colourless residue of the aminopyrimidine which is recrystallised from *C6H6 (toluene could also be used) which forms needles at first, then prisms. It melts with sublimation. Acetylation yields 5-acetamidopyrimidine which crystallises from *C6H6, m 148-149o. [Whittaker J Chem Soc 1565 1951.]