Copper(I)-Catalyzed Azide-Alkyne Cycloaddition Microwave-Assisted: Preparation of 7-(4-Substituted-1H1,2,3-Triazol-1-yl)-Fluoroquinolones

Abstract

Nowadays, the pharmaceutical industry faces the challenge of innovating and increasing the productivity of new medicines due to the increasing multidrug resistance among bacteria, viruses and fungi. The main objective of the present study is connected quinolone and triazole molecules to enhance and broad antibacterial spectrum as well as to have multiple mechanisms of action. Preparation of 4-substituted-1H-1,2,3-triazol-1-yl in C-7 of 6-fluoro- and 6,8-difluoro-quinolone ring is showed. The synthesis involved the preparation of intermediate ethyl 7-azide-1-ethyl-fluoroquinolone-3-carboxylate, followed by copper(I)-catalyzed azide-alkyne cycloaddition to give 13 derivatives. The cycloaddition was carried out by two different methods, where it was observed that the microwave radiation was the best reaction condition, obtaining a range of yields of 47–93%, at 140 °C, 125Wmax for 10 minutes. Therefore, this methodology provided an easy pathway to synthesize a library of fluoroquinolones coupled to 1,2,3-triazole, still unexplored.