Sulfuric Acid → 4-Iodophthalonitrile

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Reaction Steps

4-Aminophthalonitrile (40 g, 0.28 mol) was slowly added to 80 ml of concentrated sulfuric acid and the mixture was stirred with cooling (below 25° C.) until dissolution was complete. After cooling below 15° C., ice water (175 ml) was slowly added to precipitate the amine bisulfate. A solution of sodium nitrite (20 g, 0.29 mol) in 40 ml of water was then added at such a rate as to maintain the temperature at 0°-10° C. After stirring the solution for an additional 15 minutes, a few crystals of urea were added to decompose any excess sodium nitrite. The homogeneous solution was then poured into a breaker containing potassium iodide (75 g, 0.45 mol) dissolved in 150 ml of water. After the evolution of nitrogen had ceased and a negative test with alkaline p-methoxyphenol indicated that the reaction was complete, the brown precipitate was collected by suction filtration and washed with 10% sodium bisulfite, with saturated sodium bicarbonate and finally with water. Recrystallization from ethanol-water afforded 51 g (72%) of the desired product, m.p. 141°-142° C.

Provenance & Evidence