Photoreaction of pyrido[2,3-c]furoxan

When pyrido[2,3-c]furoxan 4 was irradiated in acetonitrile containing a little water with a low pressure mercury lamp, 3-nitro-2-pyridone 5 was obtained. When compound 4 was irradiated in the presence of morpholine with a low pressure mercury lamp in an argon atmosphere, 6-morpholinopyridine 2,3-dioxime 6 , 6-morpholinopyrido[2,3-c]furazan 7 , 3-amino-6-morpholino-2-nitropyridine 8 , and 3-amino-4,6-dimorpholino-2-nitropyridine 9 was produced. The results of photoreaction study indicated the only photo-product to be compound 6 . The main difference between these two reactions may be considered due to the behavior of nitrogen in the pyridine ring.