Toward benign syntheses of pyridines involving sequential solvent free aldol and Michael addition reactions

Krohnke type pyridines are readily accessible via a sequential solventless aldol condensation and Michael addition involving solid NaOH, followed by treatment with ammonium acetate in acetic acid, as a one pot reaction, which enables both symmetrical and unsymmetrical 2,6-bisaryl substituted pyridines to be isolated in high yield, typically >75%.