A Novel and Facile Synthesis of 2-(Benzofuran-2-yl)benzo[h]quinoline-3-carboxylic Acid Derivatives

A simple and concise approach for the synthesis of a series of new heterocyclic systems of 2-(benzofuran-2-yl)benzo[h]quinoline-3-carboxylic acid derivatives (3a3g) is described. The synthetic strategy features the one-pot reaction of ethyl 2-(chloromethyl)benzo[h]quinoline-3-carboxylate (2) with various substituted salicylaldehydes as well as 2-hydroxy-1-naphthaldehyde as a key step. The substrate 2 was prepared in good yield by a mild, efficient and direct reaction of 1-naphthylamine (1) with Vilsmeier-Haack reagent. The structures of all the new compounds were identified by spectral data and elemental analysis.