p-Toluenesulfonic acid → Ethyl 3-amino-4-(trifluoromethyl)benzoate

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Reaction Steps

To a solution containing 5.62 g. of anhydrous p-toluenesulfonic acid pre-dissolved in 100 ml. of anhydrous ethanol and 500 ml. of benzene is added 6.1 g. of 2-amino-α,α,α-trifluoro-p-toluic acid. The solution is refluxed under an extractor containing a thimble of anhydrous magnesium sulfate for 11 days with periodic replacement of the drying agent. The resultant solution is then cooled, neutralized with 2 N sodium hydroxide and the organic layer is separated, washed with 2 N sodium hydroxide, and then with brine. After drying the organic solution over anhydrous magnesium sulfate, the solvents are removed on a rotary evaporator and the resulting crystals are dried to yield 2-amino-α,α,α-trifluoro-p-toluic acid ethyl ester (4-trifluoromethylanthranilic acid ethyl ester), m.p. 38°-39° C.

Provenance & Evidence