An unusual result of the reaction of α-acetylene aldehydes, pyridines, and malonic acid. Synthesis and structure of novel pyridine betaines
5-Aryl-2-carboxy-5-(pyridin-1-ium-1-yl)penta-2,4-dienoates, previously unknown pyridine betaines, were formed in 32–70% yields as a result of the reaction of arylpropynals, substituted pyridines, and malonic acid instead of the expected 5-arylpent-2-en-4-ynoic acids. The molecular structure of the novel compounds was studied by X-ray structural analysis.