Synthesis of norfloxacin analogues catalyzed by Lewis and Brönsted acids: An alternative pathway
                                
                                    
                                        作者:Socorro Leyva、Hiram Hernández                                    
                                    
                                        DOI:10.1016/j.jfluchem.2010.07.002
                                    
                                    
                                        日期:2010.10
                                    
                                    An alternative synthetic pathway to prepare norfloxacin analogues is presented. Three Lewis acids (CeCl3 center dot 7H(2)O, AlCl3 center dot 6H(2)O, ZnCl2) and one Bronsted acid (TsOH) were tested as catalysts in the preparation of 3,4-difluoroacrylate. Cyclization of this acrylate at 55 degrees C was achieved with the use of Eaton's reagent (P2O5/MeSO3H) a known Bronsted acid. The fluoroquinolone-boron complex presented high yields on C-7 nucleophilic substitution of the fluorine atom by different heterocyclic amines with low, medium and strong nucleophilic character. (C) 2010 Elsevier B.V. All rights reserved.