Hydrochloric Acid → 3'-Fluoro-4'-methoxy-[1,1'-biphenyl]-4-carboxylic acid

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Reaction Steps

The resulting 4-acetyl-3'-fluoro-4'-methoxybiphenyl (7.2 g) was dissolved in 300 ml of dioxane, and 360 ml of a solution of sodium hypobromite (prepared from 75 g of sodium hydroxide and 78 g of bromine) was added over about 40 minutes at 0° to 5° C., and the mixture was stirred at 30° to 35° C. for 2 hours. The excess of sodium hypobromite was decomposed with a saturated aqueous solution of sodium hydrogen sulfite, and 10% hydrochloric acid was added to adjust the pH of the solution to 3 to 4. The solution was left to stand at 10° C. for 20 hours to permit crystallization. The resulting crystals were filtered to give 7.2 g of 3'-fluoro-4'-methoxybiphenyl-4-carboxylic acid. Recrystallization from isopropyl alcohol gave 6.8 g of the desired product. Yield 94%.

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