4-Aminobenzoic Acid → 4-[(4-Methylbenzene-1-sulfonyl)amino]benzoic acid

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Reaction Steps

A mixture of 190.5 g (1 mole) of 4-toluenesulfonyl chloride in 300 ml of i-propyl ether is added dropwise at 20-30° C. to one of 252 g (3 mole) of sodium bicarbonate and 139.1 g (1 mole) of 4-aminobenzoic acid in 2.5 l of water. The mixture is stirred vigorously for 2-4 hours, until the sulfonyl chloride has been consumed. The aqueous solution is separated off and then adjusted to pH 1 with concentrated hydrochloric acid, and the precipitate is taken up in propyl acetate. The extract is washed 2× with 2N hydrochloric acid and 1× with water, dried over sodium sulfate and evaporated. 240 g (82.5% of theory) of N-(4-carboxyphenyl)-4-toluenesulfonamide are obtained.

Provenance & Evidence