Novel naphthyridine-, and quinolinecarboxylic acids as antibacterial agents are described as well as methods for their manufacture, formulation, and use in treating bacterial infections including the description of certain novel intermediates used in the manufacture of the antibacterial agents.
In the search for new potent antiparasitical fluoroquinolones, a QSAR analysis by molecular connectivity led to the design of R-5 (Me or Et)/R-8 (MeO, Me or Et)-substituted analogs of the most powerful antibacterial or antiparasitical fluoroquinolones known so far. Unfortunately, the synthetic schemes that were elaborated in literature for 3- and 3,6-di-substiluted 2,4,5-trifluorobenzoic acids, the key precursors of the target R-5/R-8-substituted 6-fluoroquinolones, led in our hands to poor yields and/or to inextricable mixtures of derivatives. This led us to reinvestigate the key alkylation steps or the 2,4,5-trifluorophenyl-oxazoline synthons and the subsequent deprotection of their oxazoline into acid with the aim of optimising the syntheses of 3- and 3,6-di-Substituted 2.4,5-trifluorobenzoic acids, which constitute the entries to our target derivatives. (c) 2005 Elsevier Ltd. All rights reserved.