Formation of zwitterionic salts via three-component reaction of 2,6-dimethylpyridine, barbituric acid and dialkyl acetylenedicarboxylate

A zwitterion, an ion pair where cation and anion are covalently tethered, is known to be a kind of salt. The charges on the different functional groups balance each other out, and the molecule as a whole is electrically neutral1. N-heterocycle zwitterions are reactive species that are widely used in organic synthesis, pharmaceuticals and bioinorganic chemistry.2-4 Pyridine zwitterions are usually synthesized via the addition of pyridine derivatives to reactive double bonds or carbenes.5-7 There are also some recent reports on the synthesis of N-heterocycle zwitterions by multi-component reactions.8-10 Here we wish to report the result of our study on the reaction of 2,6-imethylpyridine 1, barbituric acid 2 and dimethyl or diethyl acetylenedicarboxylate 3 in dry acetonitrile as solvent lead to products 4 (Fig. 1). The structures of this products were proved by 1H-NMR, 13C-NMR and IR spectral data and elemental analysiss.

کلیدواژه ها:

zwitterion ، barbituric acid ، 2 ، 6-dimethylpyridine ، dialkyl acetylenedicarboxylate