Metallation of 2,4-Dialkoxy-5-bromopyrimidine and Formylation with Dimethylformamide: Isolation of 2,6-Dialkoxy-5-dimethylaminopyrimidine-4-carboxaldehyde

Abstract

Direct metallation of 2,4-dialkoxy-5-bromopyrimidine with lithium diisopropylamide and consequent trapping by dimethylformamide resulted unexpectedly in the formation of 2,6-dialkoxy-5-dimethylaminopyrimidine-4-carboxaldehyde via displacement of bromine by dimethylamine moiety of dimethylformamide.

Keywords:

• 2,4-Dialkoxy-5-bromopyrimidine
• formylation
• metallation

ACKNOWLEDGMENTS

We are grateful to the Council for Scientific and Industrial Research, New Delhi [No. 01(2215)/08/EMR-II], for financial support of this work. The University Grants Commission, New Delhi, is also thanked for the award of a junior research fellowship to S. M.

Notes

^a Condition A: t₁ = 10 min, t₂ = 1 h, quenched at rt; condition B: t₁ = 30 min, t₂ = 15 min, quenched at −78 °C; condition C: t₁ = 30 min, t₂ = 1 h, quenched at −78 °C; condition D: t₁ = 2 h, t₂ = 2 h, quenched at −78 °C; where t₁ is time of addition of DMF after adding starting material and t₂ is time of stirring after DMF addition at −78 °C.

^b Isolated yield.