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The general procedure for the synthesis of 2,3-diamino-4-chloropyridine from 2-amino-3-nitro-4-chloropyridine was as follows: 2-amino-3-nitro-4-chloropyridine (2 g, 11.52 mmol, 1.00 equiv) was dissolved in a mixture of 20 mL of solvent of n-propanol and water in a 100 mL round bottom flask. Iron powder (3.23 g, 57.84 mmol, 5.02 eq.) and ammonium chloride (3.06 g, 57.21 mmol, 4.96 eq.) were sequentially added to the reaction system at room temperature. The reaction mixture was stirred at 70 °C for 2 hours. Upon completion of the reaction, the mixture was cooled to room temperature and thermally filtered through a diatomaceous earth pad. The filtrate was concentrated under reduced pressure to afford the target product 2,3-diamino-4-chloropyridine (1.6 g, 97% yield) as a black solid.

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