Amination of 4-nitro- and 4-cyanopyridazines by liquid ammonia/potassium permanganate

4-Nitro-3- R ¹-6- R ²-pyridazines ( 1 ) ( a, R ¹ = R ² = 2-pyridyl; b, R ¹ = H, R ² = phenyl; e, R ¹ = H, R ² = p-methoxyphenyl; d, R ¹ = R ² = H ) are aminated by liquid ammonia/potassium permanganate to the corresponding 5-amino-4-nitropyridazines 3a-d. The 4-cyano-3-R¹-6-R²-pyridazines 4a,b are only aminated in the presence of potassium amide in liquid ammonia/potassium permanganate to give the 5-amino-4-cyanopyridazines 6a,b. The 5-amino-4-nitropyridazines 3a,b,d are converted to the 4,5-diaminopyridazines 7a,b,d by reduction over a Pd/C catalyst. Reaction of 7b with glyoxal leads to 5-phenylpyrazino2,3-d]pyridazine ( 8b ).