α-Pyrones. Part V. Structure Effects on the Intramolecular Cyclization of Functionalized 6-Pyronylacetamides: Synthesis of New 2,5,7-Trioxo-pyranopyridines

Article abstract of DOI:10.1016/0040-4020(95)00050-I

Reaction of arylisocyanates 2 with methyl 2-oxo-2H-pyran-6-acetate 1 and with ylide 4 gave two classes of pyronylacetamides 3 and 5, respectively.Phosphoranes 5 were reduced to the corresponding acetamides 6 with zinc and acetic acid.Compounds 6 were alky