Kröhnke pyridine synthesis

What is Kröhnke pyridine synthesis?

The Kröhnke pyridine synthesis involves the 1,4-Michael addition of α-pyridinium methyl ketone salts to α,β-unsaturated ketones, which results in the formation of 1,5-dicarbonyl compounds. These compounds are then subjected to a ring closure process, catalyzed by ammonium acetate, leading to the production of substituted pyridines.

Síntesis pyridine synthesis
Kröhnke pyridine synthesis

References

  • Zecher, W. and Kröhnke, F. (1961), Eine neue Synthese substituierter Pyridine, I. Grundzüge der Synthese. [A new synthesis of substituted pyridines, I. Main features of the synthesis.] Chem. Ber., 94: 690-697. https://doi.org/10.1002/cber.19610940317
  • Zecher, W. and Kröhnke, F. (1961), Eine neue Synthese substituierter Pyridine, II. Einige Varianten und Sonderfälle. [A new synthesis of substituted pyridines, II. Some variants and special cases.] Chem. Ber., 94: 698-706. https://doi.org/10.1002/cber.19610940318
  • Kröhnke, F., Zecher, W., Curtze, J., Drechsler, D., Pfleghar, K., Schnalke, K.E. and Weis, W. (1962), Syntheses Using the Michael Adddition of Phridinium Salts. Angew. Chem. Int. Ed. Engl., 1: 626-632. https://doi.org/10.1002/anie.196206261

 

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