Synthesis and reactions of dinitrated amino and diaminopyridines

Nitration of amino‐ and diaminopyridines and ‐picolines led, in unexpected one‐step reactions, to dinitrated derivatives. Dinitropicolines gave styrylpyridines, and 2‐amino‐6‐hydroxy‐3,5‐dinitropyridine was transformed by the thermolysis of its azido derivative into 5‐amino‐6‐nitro[1,2,5]oxadiazolo[3,4‐b]pyridine. Using 1H and 13C nmr spectroscopy, azido‐tetrazole tautomerism of 2‐amino‐6‐azido‐3,5‐dinitropyridine and intramolecular hydrogen bonding at 20° for several 2‐amino‐3,5‐dinitro‐6‐R‐pyridines have been proved.