Ammonia → 2-Chloro-4-nitroaminopyridine

Participants

Reaction Steps

357.5 g of 2-chloropyridin-4-amine were added in portions to 2.28 l of cold concentrated sulfuric acid. 0.86 l of nitric acid (90%) were slowly added so that the temperature of the reaction mixture always stays below 10° C. After the addition the mixture was stirred for one hour at room temperature and poured into 4 l of water containing 10 kg of ice. 6.2125% (w/v) aqueous NH3 solution were slowly added. The resulting precipitate was filtered, washed with ice water and dried under vacuum to give 316.6 g of the 2-chloro-N-nitropyridin-4-amine. 316.2 g of this intermediate compound were treated with 2.35 l concentrated sulfuric acid and stirred for 30 minutes at 88-94° C. The mixture was cooled to room temperature and poured into 2 l of water containing 5 kg ice. 6.5 l 25% (w/v) aqueous NH3 solution were slowly added. The resulting precipitate was filtered and pre-dried under reduced pressure. Finally the residue was dried by azeotropic distillation with benzene. After crystallization from benzene the title compound was obtained.

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