Editing Pyrimidine (section)

==Reactions==
Because of the decreased basicity compared to pyridine, electrophilic substitution of pyrimidine is less facile. [[Protonation]] or [[alkylation]] typically takes place at only one of the ring nitrogen atoms. Mono-''N''-oxidation occurs by reaction with peracids.<ref name="JouleMills5th"/>{{rp|253–254}}

[[Electrophilic]] ''C''-substitution of pyrimidine occurs at the 5-position, the least electron-deficient. [[Nitration]], [[nitrosation]], [[azo coupling]], [[halogen]]ation, [[sulfonation]], [[formyl]]ation, hydroxymethylation, and aminomethylation have been observed with substituted pyrimidines.<ref name="BrownPyrimidines1994"/>{{rp|9–13}}

[[Nucleophilic]] ''C''-substitution should be facilitated at the 2-, 4-, and 6-positions but there are only a few examples. Amination and hydroxylation have been observed for substituted pyrimidines. Reactions with Grignard or alkyllithium reagents yield 4-alkyl- or 4-aryl pyrimidine after aromatization.<ref name="BrownPyrimidines1994"/>{{rp|14–15}}

Free radical attack has been observed for pyrimidine and photochemical reactions have been observed for substituted pyrimidines.<ref name="BrownPyrimidines1994"/>{{rp|15–16}} Pyrimidine can be hydrogenated to give tetrahydropyrimidine.<ref name="BrownPyrimidines1994"/>{{rp|pages=17}}