Abstract
As a part of our search for new antibacterial agents, 5-ethyl-8-oxo-5, 8-dihydrofuro [3, 2-b]-[1, 8] naphthyridine-7-carboxylic acid and its 2, 3-dihydrofuro derivative, the 4-aza analogue of droxacin, were synthesized and their antibacterial activities were tested. Both compounds exhibited high antibacterial activities and a broad antibacterial spectrum. In an attempt to find a suitable method for industrial-scale synthesis of these compounds, several methods for the furan ring cyclization of 6, 7-disubstituted 1, 8-naphthyridine-3-carboxylate derivatives were compared.
