Polycyclic N ‐heterocyclic compounds. 48 . syntheses of furo[2,3‐ h ]‐[1,6]naphthyridine and imidazo(or pyrimido)[2,1‐ f ]‐[1,6]naphthyridines with rearrangement

The formation of a novel ring system, furo[2,3‐ h ][1,6]naphthyridine via the Smiles rearrangement and intramolecular cyclization is described. Cyclization of 5‐(ω‐hydroxyalkylamino)‐8‐methyl‐1,2‐dihydrofuro[2,3‐ h ][1,6]naphthyridines provided novel spiro compound with rearrangement.