Kinetics of reactions in heterocycles. Part XII. Substituted N-methylquinolinium and N-methylisoquinolinium salts with hydroxide ions

Abstract

Kinetics of the replacement reactions of chloro-, iodo-, methoxy-, and methylthio-subsittuted N-methylquinolinium and N-methylisoquinolinium iodides with hydroxide ions have been determined. The 2-iodo- and 2-methylthioquinolinium salts at 20° were 1440 and 1490 times more reactive than their 4-isomers respectively, owing to lower energies of activation and higher frequency factors. The reactivity of 1-methylthioisoquinoline methiodide was anomalous, being 530 times greater than that of 2-methylthioquinoline methiodide. N-Methylation of the iodoquinolines and -isoquinolines increased their reactivity towards hydroxide ions at 114·8° by 1·2–3·4 × 10⁷ fold for substituents at the α-position, and 6·1 × 10⁵ fold for substituents at the γ-position of quinoline. U.v. and ¹H n.m.r. spectra are recorded and discussed.