A NEW APPROACH TO IMIDAZO1,2-aPYRIDINE DERIVATIVES AND THEIR APPLICATION TO THE SYNTHSES OF NOVEL 2H-PYRANO2',3':4,5 IMIDAZO1,2-aPYRIDIN-2-ONE DERIVATIVES

摘要

3-Bis(methylthio)methylene-2(3H)-imidazo1,2-apyridinones were prepared from the S-alkylation of pyridinium 1-1-carbamoyl-1-(methylthio) thiocarbonylmethylides with methyl iodide followed by the alkaline treatment of the resulting pyridinium salts. The reactions of these 3-methylene-2(3H)-imidazo1,2-apyridinones with some ethyl cyano- or acyl-substituted acetates in the presence of a base did not afford the initially expected 2H-pyrano2',3':4,5imidazo1,2-apyridine-2-one derivatives, but, instead of them, provided ethyl 3-2-hydroxyimidazo1,2-apyridin-3-ylacrylates. The thermolyses of these acrylates without any solvent under reduced pressure gave the corresponding 2H-pyrano2',3':4,5imidazo1,2-apyridine-2-one derivatives.