153463-65-1

Example 22A: 3,5-Dichloro-4-pyridinecarboxaldehyde (10.0 g, 57.1 mmol) was mixed with hydroxylamine hydrochloride (5.25 g, 76 mmol), formic acid (50 mL) and sodium bisulfate (5 drops). The mixture was refluxed for 6 hours under nitrogen protection. Upon completion of the reaction, the solvent was removed by vacuum concentration. The resulting solid was dissolved in ether (250 mL), washed sequentially with sodium bicarbonate solution and brine, and the organic phase was dried with magnesium sulfate. After filtration, the organic phase was concentrated and finally recrystallized from hexane to give 8.2 g of the target product, 3,5-dichloroisonicotinonitrile, in 83% yield with a melting point of 114 °C.

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