2,6-Diaminopyridine → HCID 57710474, compound

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Reaction Steps

In a second embodiment, the present invention further comprises the composition 2,6-diamino-3-nitropyridine-5-sulfonic acid (DANPS). This is the intermediate formed during the process of the present invention described above, which is undesirable in the diaminodinitropyridine product. 2,6-Diamino-3-nitropyridine-5-sulfonic acid is prepared by dissolving 2,6-diaminopyridine or 2,6-diaminopyridine hemisulfate salt in oleum to form 2,6-diaminopyridine-3-sulfonic acid and treating the resulting solution with one stoichiometric amount of concentrated (98%) nitric acid. The resulting 2,6-diamino-3-nitropyridine-5-sulfonic acid is isolated by slowly drowning the reaction mix in an excess of 20% sulfuric acid followed by filtration, and washing the filter cake with water and 5% aqueous ammonium hydroxide solution and drying. 2,6-Diamino-3-nitropyridine-5-sulfonic acid is useful as a chemical intermediate, for instance as a dye intermediate.

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