Synthesis of 2-heptyl-1-hydroxy-4(1H)-quinolone - Unexpected rearrangement of 4-(alkoxycarbonyloxy)quinoline N-oxides to 1-(alkoxycarbonyloxy)-4(1H)- quinolones

Abstract

2-Heptyl-4(1H)-quinolone was converted in two steps into the 4-ethoxycarbonyloxy-, 4-(tert-butoxycarbonyloxy)-, and 4- (dimethylaminocarbonyloxy)quinoline N-oxides. While the former two rearranged to the corresponding 1-(alkoxycarbonyloxy)-4(1H)-quinolones at room temperature, the latter was stable, even at 140°C in refluxing xylenes. Basic hydrolysis of these compounds furnished 2-heptyl-1-hydroxy-4(1H)-quinolone. © Georg Thieme Verlag Stuttgart.