Hydrochloric Acid → 4,5-Bis(4-methoxyphenyl)-2-(4-trifluoromethylphenylthio)imidazole

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Reaction Steps

6.25 g of 4,5-bis(4-methoxyphenyl)-2-mercaptoimidazole is dissolved in 150 ml of absolute dimethylformamide and combined with 0.60 g of sodium hydride (80% in oil). After the evolution of hydrogen has ceased, the solution is cooled to 0°, combined with a pinch of powdered copper, and then a diazonium salt solution, cooled to 0° and prepared from 3.26 g of 4-trifluoromethylaniline (99%), 1.38 g of sodium nitrite, as well as 10 ml of 6 N hydrochloric acid, is added dropwise to the reaction mixture. The latter is agitated for 30 minutes at 0° and then allowed to warm up to room temperature. The solution is then concentrated under vacuum, the residue is distributed between water and ethyl acetate; the organic solution is dried over sodium sulfate and concentrated to dryness under vacuum. The residue is chromatographed on 500 g of aluminum oxide, neutral, activity stage II, with hexane/ethyl acetate 3:2 as the eluting agent. Elution yields 3.39 g of 4,5-bis(4-methoxyphenyl)-2-(4-trifluoromethylphenylthio)imidazole, mp 179°-181°.

Provenance & Evidence