STUDIES ON THE MECHANISM OF THE NITRAMINOPYRIDINE REARRANGEMENT

The rearrangement of 2-nitraminopyridine and of its 3-,4-,5-,6-methyl,5-bromo, and 3-nitro derivatives in conc sulphuric add has been investigated. 5-Methyl-2-nitraminopyridine appears to react by a different mechanism from the rest, as a considerable amount of 5-methyl-2-pyridone is also formed. For the others, results at variance with other reports are presented, trans-Nitration studies have established that free nitronium ions are produced, second order kinetics are followed, and the rate is equally enhanced by the addition of aminopyridine or potassium nitrate. However, the observation of a 1:1.5 mixture of 3- and 5-nitro products from 4-methyl-2-nitraminopyridine makes a normal SeAr mechanism unlikely. © 1979.