| Abstract: | The new benzofuro2,3-b]naphthyridine ring system was prepared. 2,4-Dichloro-3-(o-methoxyphenyl)naphthyridines 3a and 3b were obtained by chlorination of hydroxynaphthyridinones 2a and 2b . Demethylation followed by cyclization of 3a and 3b afforded 11-chlorobenzofuro2,3-b]naphthyridines 4a and 4b . Hydrogenolysis of these 11-chlorobenzofuronaphthyridines gave the parent benzofuro2,3-b]naphthyridines 5a and 5b . The analog 4b was also converted to 11-methoxybenzofuro2,3-b]1,8]naphthyridine ( 6 ). |
