Selective vicarious nucleophilic amination of 3-nitropyridines

Nine 3-nitropyridine compounds and 4-nitroisoquinoline have been aminated in the 6-position (for 4-nitroisoquinoline in the 1-position) by vicarious nucleophilic substitution reactions. Two amination reagents were used, hydroxylamine and 4-amino-1,2,4-triazole. The yields were from moderate to good. Use of hydroxylamine gave an easy work-up procedure by which almost pure product was obtained directly, but 4-amino-1,2,4-triazole gave better yields of the aminated product for some of the substrates. By this, a general method for the preparation of 3- or 4-substituted-2-amino-5-nitropyridines was obtained.