Baeyer pyridine synthesis

What is Baeyer pyridine synthesis?

The Baeyer pyridine synthesis, first discovered by von Baeyer in 1910, involves the conversion of γ-pyrones or other pyrone derivatives into pyridines by utilizing pyronium salt intermediates, which subsequently react with an ammonium salt like ammonium carbonate (NH4)2CO3. This reaction can also be utilized for the preparation of various other types of nitrogen-containing heterocycles.

Baeyer pyridine synthesis - γ-pyrones - pyronium salt intermediates - ammonium carbonate (NH4)2CO3
Baeyer pyridine synthesis

Several alternative approaches have been developed to synthesize pyridines, which include the distillation of allylethylamine over heated lead oxide, the passage of a mixture of acetylene and hydrocyanic acid through a red-hot tube, heating pyrrole with sodium methylate and methylene iodide to 200 ºC, heating isoamyl nitrate with phosphorus pentoxide, and heating piperidine in acetic acid with silver acetate, but these methods usually produce low yields of pyridine derivatives.

References

Baeyer, A. (1910), Über die Einwirkung von Dimethylsulfat auf Dimethyl-pyron. [On the effect of dimethyl sulfate on dimethyl-pyrone.] Ber. Dtsch. Chem. Ges., 43: 2337-2343. https://doi.org/10.1002/cber.191004302198

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