3-Chloro-4-hydroxybenzoic acid → 3-Chloro-5-(chlorosulfonyl)-4-hydroxybenzoic acid

Participants

Reaction Conditions

Reaction Steps

To a flask charged with chlorosulfonic acid (13.9 mL, 209.0 mmol) was added 3-chloro-4-hydroxybenzoic acid (6.0 g, 34.8 mmol) portionwise over ten minutes. The mixture was then heated for 2 h at 65° C. under a nitrogen atmosphere. After cooling the mixture to room temperature, the reaction mixture was carefully poured over crushed ice with vigorous stirring, and extracted with Et2O until no further product remained in the aqueous layer. The combined organic extracts were dried over anhydrous Na2SO4, filtered and concentrated in vacuo to afford 3-chloro-5-(chlorosulfonyl)-4-hydroxy-benzoic acid as a white solid (7.0 g, 74%) which was used without further purification.

Provenance & Evidence