NMR study of O and N, O-substituted 8-quinolinol derivatives

The 1H and 13C NMR spectral study of several biologically active derivatives of 8‐quinolinol have been made through extensive NMR studies including homodecoupling and 2D‐NMR experiments such as COSY‐45°, NOESY, and HeteroCOSY. Electron donating resonance and electron withdrawing inductive effect of several groups showed marked changes in chemical shifts of nuclei at the seventh positions of O‐substituted quinolinols (2–15). Although in N‐alkyl, 8‐alkoxyquinolinium halides (16–21), ring A rightly showed low frequency chemical shift values. Copyright © 2013 John Wiley & Sons, Ltd. Electron donating and withdrawing effect of different substituents on 1H and 13C NMR chemical shift values of 8‐quinlinol derivatives has been presented. This may serve as reference data for future studies on quinoline compounds.