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

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 degrees C in refluxing xylenes. Basic hydrolysis of these compounds furnished 2-heptyl-1-hydroxy-4(1H)-quinolone.