Interesting Synthetic Approaches towards [1] Benzopyrano[4,3- b ]quinolines via Intramolecular Reaction of Nitrilium Salts

Abstract

The o-allyloxybenzanilides 2a,b,d and o-propargyloxybenzanilides 3a–f are prepared and converted to the corresponding dihydro[1]benzopyrano[4,3-b]quinolinium hexachloroantimonate 6a and [1] benzopyrano[4,3-b] quinolines 9a–e, 10 upon treatment with PCI₅ followed by SbCI₅.