The present invention relates to a process comprising reacting p-fluorobenzaldehyde, 4-methyl-3-oxopentanenitrile and
urea in a first reaction mixture comprising a first
organic solvent, thereby obtaining an intermediate mixture comprising an oxo-
pyrimidine-carbonitrile; and oxidizing the oxo-
pyrimidine-carbonitrile by contacting the intermediate mixture or organic extract with an organic hydroperoxide, thereby obtaining a hydroxyl-
pyrimidine carbonitrile.