Study of the reactions of 3-chloro-4-cyanobenzo[b][1,6]naphthyridine with nucleophilic reagents

The reactions of 3-chloro-4-cyanobenzo[b][1,6]naphthyridine (4) with S-, C-, and N-nucleophiles afford stable s-adducts at position 10. In the base-catalyzed reactions of compound 4 with thiols, the resulting σ-complexes are rearranged into sulfides 14a—c. Sulfides 14b,c undergo the Thorpe—Ziegler cyclization to give 1-aminobenzo[b]thieno[2,3-h][1,6]naphthyridine derivatives 15a,b. The reaction of naphthyridine 4 with aniline affords a mixture of σ-adducts of the C—N and C—C types, while those with aliphatic amines yield 3-amino derivatives 17a—c. In the presence of H2O2, benzonaphthyridine 4 adds peroxycarboxylic acids to give compounds 8a,b. In alkaline medium, adduct 8a is rearranged into 4-aminopyridine-3-carbaldehyde derivative 10.