Bromide ion → (4-Chloro-2-hydroxyphenoxy)acetic acid

Participants

Reaction Steps

To a solution of 48% aqueous hyrdrogen bromide (20 mL) was added (4-chloro-2-methoxy-phenoxy)-acetic acid (2.1 g, 9.7 mmol). The resulting mixture was heated to reflux overnight. The mixture was cooled to ambient temperature, diluted with water and extracted with diethyl ether. The organic layer was dried over magnesium sulfate, filtered and concentrated in vacuo to give (4-chloro-2-hydroxy-phenoxy)-acetic acid. The crude product was added to a solution of pyridinium p-toluene sulfonate (0.10 g, 0.40 mmol) in toluene (100 mL). The resulting mixture was heated to reflux for five hours. The reaction was allowed to cool to ambient temperature and concentrated in vacuo. Chromatography on silica gel gave the title compound (0.97 g).

Provenance & Evidence