Quinoline 1-oxide, halogeno-, reactions

Okamoto et al. found that A-oxidation activates 4-halogeno-quinolines in the reaction with piperidine in aqueous alcohol by kinetic factors of 9 to 25, at 100°. This rate-enhancing effect is accompanied by a fairly large decrease in the enthalpy of activation (up to 10 kcal/mole in the chloro compounds), the effect of which is partly offset by a decrease in the entropy of activation. 

Second-order kinetics are reported for the reactions of halogeno-quinoline iV -oxides with piperidine in several solvents and of halo-geno-nitrothiophenes with piperidine in ethanol. ... 

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