Kinetics of reactions in heterocycles. Part XIV. Reactions of 2- and 4-amino-, -methylamino-, and -dimethylamino-pyridine methiodides and 2-methylthiopyrimidine methiodide with hydroxide ions in water

Abstract

The kinetics of the reactions of 2- and 4-amino-, -methylamino-, and -dimethylamino-pyridine methiodides with hydroxide ions in water have been studied. At 20 °C, 2-dimethylaminopyridine methiodide was 8.5 × 10³ times more reactive than its 4-isomer, owing mainly to a lower energy of activation (by 6.4 kcal mol^–1). The 2- and 4-dimethylaminopyridine methiodides were 2.3 × 10^–4 and 3.1 × 10^–6 times less reactive than their chloroanalogues. The reaction of 2-methylthiopyridine methiodide with hydroxide ions was found to proceed via a two-step process.