An Improved Liquid-Phase Synthesis of Simle Alkylpyridines

Article abstract of DOI:10.1002/hlca.19840670811

The synthesis of pyridines from mixtures of aldehydes or ketones and NH3 in the liquid phase has been reinvestigated, using continuous dosage of the carbonyl components to the reaction mixture.The main product from the reaction of acetaldehyde and formaldehyde is 3-methylpyridine (6), which is also the main product from the reaction of acrolein or a mixture of crotonaldehyde and formaldehyde under the same conditions.The reaction of other aldehydes with formaldehyde give 3,5-dialkylpyridines, e.g. 10, 16.Acetone reacts with either formaldehyde or acetaldehyde to give polysubstituted alkylpyridines.A mechanistic pathway is proposed which accounts for the formation of the observed products.