Reaction of Picolinamides with Ketones Producing a New Type of Heterocyclic Salts with an Imidazolidin-4-One Ring.

Reactions of picolinamides with 1,3-propanesultone in methanol followed by the treatment with ketones led to a series of previously unknown chemical transformations, yielding first pyridinium salts ( 2a - f ), with a protonated endocyclic nitrogen atom, and then heterocyclic salts ( 3a - j ) containing an imidazolidin-4-one ring. The structures of intermediate and final products were determined by IR and 1 H, 13 C NMR spectroscopy, and X-ray study. The effects of the ketone and alcohol structures on the product yield were studied by quantum-chemical calculations. The stability of salts 3a - j towards hydrolysis and alcoholysis makes them excellent candidates for the search for new types of biologically active compounds.