Transformations of 10-Substituted Tetrahydrobenzo[b][1,6]naphthyridines through Interaction with Dehydrobenzene
The regioselectivity of dehydrobenzene reaction with 10-substituted benzo[b][1,6]naphthyridines was found to depend on electronic effects due to the C-10 substituent. Stevens rearrangement of 10-cyano-substituted naphthyridines produced 1-alkyl-2-phenyltetrahydrobenzonaphthyridines. 10-Carbamoyl-substituted naphthyridines underwent Hoffman cleavage of the tetrahydropyridine ring, giving 3-phenylallylaminomethyl-2-vinylquinolines.