Potassium Cyanide → 2,6-Difluoro-4-iodobenzonitrile

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Reaction Steps

12 g of sodium nitrite was dissolved in 91 ml of sulfuric acid and cooled to 10° C or less, and then 100 ml of acetic acid was added. At 20 to 25° C, 39 g of the 2,6-difluoro-4-iodoaniline from Step 3 was added to the solution, and then the solution was agitated for one hour. A second solution was made by dissolving 37 g of copper sulfate pentahydrate in 91 ml of water to which was added 62 g of ice, and this solution was added to the first. A third solution containing 39 of potassium cyanide dissolved in 92 ml of water, 221 g of sodium bicarbonate, and 91 ml of benzene was added to the first solution, and a diazonium salt sulfuric acid solution was added therein. After agitation at room temperature for 3 hours, a sodium hydroxide aqueous solution was added to dissolve the crystals. After being extracted with chloroform, the crystals were washed three times alternating with a 10% sodium hydroxide solution and water. After distillation of the chloroform, the residue was extracted with hexane, and the hexane was distilled off. This residue was recrystallized with methanol to obtain 6.7 g of 1,3-difluoro-2-cyano-5-iodobenzene.

Provenance & Evidence