Catechol → o-Toluenesulfonyl chloride

Participants

Reaction Steps

p-Toluenesulfonyl chloride (2.88 g, 15.08 mmol) was added in two portions, 30 minutes apart, to a stirring solution of pyrocatechol (1.49 g, 13.53 mmol) and potassium carbonate (2.05 g, 14.85 mmol). The solution was heated to reflux for 4 hours. The cooled solution was evaporated under reduced pressure, and the residue was taken up in ethyl acetate (100 cm3) and water (100 cm3). The aqueous layer was extracted with ethyl acetate (2×100 cm3), and the combined extracts were washed with brine (2×200 cm3), dried (MgSO4), and evaporated under reduced pressure. The residue was triturated with diethyl ether (2×20 cm3), and the precipitate was removed by filtration to give unreacted toluenesulfonyl chloride (1.10 g). The filtrate was evaporated under reduced pressure. The yellow crystals were recrystallized from ethyl acetate and heptane to give mono protected pyrocatechol, (1.65 g, 53%) as clear crystalline squares, mp 80-84° C.

Provenance & Evidence