Science of Synthesis

von Angerer, S., Science of Synthesis, (2004) 16, 501.

Pyrimidine is a π-deficient heteroaromatic system, hence Friedel–Crafts-type acylation reactions are generally not possible. However, the introduction of amino or hydroxy groups at positions 4 or 6 renders this heterocycle susceptible to a Vilsmeier-type formylation affording the corresponding pyrimidine-5-carbaldehydes ‌409‌ (‌Scheme 222‌).[‌526‌–‌528‌] At elevated temperatures the oxygen functions are replaced by chloro substituents.[‌529‌] This exchange reaction also occurs when the intermediate of the formylation is treated with N,N-dimethylaniline and phosphoryl chloride.[‌527‌]

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References

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• 8.Meeeee-Meee, (8888) M 8, 88.
• 8.Meeeee-Meee, (8888) M 8, 88.
• 8.Meeeee-Meee, (8888) M 8e8, 888.