A 2-(N-methyl-N-methanesulfonylamino)pyrimidine compound of the formula (3): [R is a hydrocarbyl group], is prepared by the steps of: (I) reacting an isobutyrylacetate ester with 4-fluorobenzaldehyde and urea in the presence of a protonic compound and a metal salt； (II) oxidizing the reaction product of the step (I)； (III) reacting the oxidation product of the step (II) with an organic sulfonyl halide or an organic sulfonyl anhydride； and (IV) reacting the reaction product of the step (III) with N-methyl-N-methanesulfonamide.
