Synthesis of some N-substituted isonicotinamides

A one-pot transformation of some cyclic 1,3-dicarbonyls 1 with N-(isonicotinoyl)glycine 2 and one-carbon synthons in acetic anhydride to the corresponding N-substituted isonicotinamides (pyridine-4-carboxamides) 7-9 containing a fused pyran-2-one ring is described. Compound 8 was further converted with some nitrogen-containing nucleophiles either to the corresponding quinoline-2,5-diones 10-11 or 5-hydrazonobenzopyran-2-ones 14-15. Under more severe conditions the compound 8 gave with hydrazine 5-hydrazonoquinoline derivative 12 or even 13. Hydrazoic acid transformed compound 8 to the pyrano[3,2-c]azepine system 16. Diazotization of 1-amino derivative 10 gave deaminated product 11.