Electro-organic reactions part 35. Efficient carbon-oxygen bond formation in the anodic coupling of pyridopyrimidine derivatives

Article abstract of DOI:10.1016/S0040-4020(01)87057-5

4-H-Pyrido[1,2-a]pyrimidine-2,4-diones (Chichibabin) derivatives, formed by condensation of 2-aminopyridines with substituted dialkylmalonates, are electroactive. In solution in CH₂Cl₂/CF₃CO₂H mixtures they are smoothly and selectively anodically coupled in high yield. The products are novel and unexpected; radical coupling at the C-3 and O-4 positions is involved and the proposed mechanism is analogous to that of oxidative phenolic coupling.