Synthetic utility of enaminoester moiety in heterocyclic synthesis

Abstract

Thieno[2,3-b]pyridine-2-carboxylate was utilized to construct a variety of new heterocyclic systems such as thienopyrimidinone, thienopyridine and pyridothienoxazinone derivatives. Treatment of pyridothienoxazinone derivative with some other nitrogen nucleophiles afforded 3-substituted-pyridothienopyramidinone derivatives. Secondary amines such as morpholine, piperidine and N-methylaniline reacted smoothly with the oxazinone derivative. When the oxazinone derivative was allowed to react with ethanol containing few drops of pyridine or formamide as a basic catalyst and heated to reflux, afforded thienopyridine ester. All the compounds were fully characterized by means of IR, MS, 1 H NMR spectra and elemental analyses.