Efficient method for the synthesis of pyranoquinoline, thiopyranoquinoline, thienoquinoline, and naphtho[2,7]naphthyridine derivatives catalyzed by iodine.

A mild and efficient method for the synthesis of pyranoquinoline, thiopyranoquinoline, thienoquinoline, and naphtho[2,7]naphthyridine derivatives via three-component reaction of aromatic aldehyde, naphthalen-2-amine, and heterocycloketones, including tetrahydropyran-4-one, tetrahydrothiopyran-4-one, pyridinone, and thiophenone, is described using iodine as catalyst. The features of this procedure are mild reaction conditions, good to high yields, and operational simplicity.