4-Toluenesulfonyl chloride → p-Toluenesulfonic acid

Participants

Reaction Steps

2.82 g (9.75 mmol) of 4-(5-bromo-1H-pyrrolo[2,3-b]pyridine-3-yl)-phenol and 3.10 g of para-toluenesulfonyl chloride were dispersed in 400 ml of toluene at 45° C. 45 ml of 50% aqueous solution of KOH and 1.5 ml of 40% aqueous solution of tetra-n-butylammonium hydroxide were added and the resulting mixture stirred vigorously at ambient temperature for 6 h. The resulting mixture was diluted with 100 ml of a saturated aqueous solution of sodium bromide, the phases separated and the aqueous layer extracted three times with toluene. The combined organic phases were washed with a 2 M aqueous solution of sodium hydroxide, dried over sodium sulfate and evaporated. The crude was crystallized from ethanol containing 10% v/v of toluene to afford 3.22 g (5.29 mmol, 55% yield) of toluene-4-sulfonic acid 4-[(5-bromo-1-(toluene-4-sulfonyl)-1H-pyrrolo[2,3-b]pyridine-3-yl]-phenyl ester as ivory crystalline needles.

Provenance & Evidence