2,3-Diaminopyridine → N-(2-amino-3-pyridinyl)-3-chlorobenzenesulfonamide

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Reaction Steps

2,3-Diaminopyridine (1.97 g, 18 mmol) was dissolved in a tetrahydrofuran/water mixture, followed by the addition of a solution of 1.90 g (9.0 mmol) of 3-chlorobenzenesulfonyl chloride in tetrahydrofuran. The obtained mixture was stirred at room temperature overnight and concentrated, followed by the addition of water and dichloromethane. The organic phase was recovered and put in a vessel and the inside wall of the vessel was scratched to precipitate crystals. The formed crystals were recovered by filtration to give 1.41 g of N-(2-amino-3-pyridinyl)-3-chlorobenzenesulfonamide. 530 mg (1.87 mmol) of the crystals was dissolved in methanol, followed by the addition of a 40% aqueous solution of chloroacetaldehyde (367 mg, 1.87 mmol). The obtained mixture was heated under reflux for 4 hours and concentrated to dryness. A small amount of methanol was added to the residue and the obtained mixture was filtered to give 373 mg of the title compound as a crystal.

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