18-Crown-6 → 3-Bromo-4-(methoxycarbonyl)benzoic acid

Participants

Reaction Conditions

Reaction Steps

A mixture of methyl 2-bromo-4-methylbenzoate (4.58 g, 20 mmol), KMnO4 (12.64 g, 80 mmol) and 18-crown-6 (1.06 g, 4.0 mmol) in t-BuOH:H2O (1:1, 60 mL) was stirred for 20 min at 75° C. Then the mixture was cooled to rt and KMnO4 (3.16 g, 20 mmol) was added. The reaction mixture was stirred for additional 1 h at 75° C. After that, the mixture was cooled to rt and KMnO4 (1.58 g, 10 mmol) was added again. The mixture was stirred for 1 h more at 75° C., cooled to rt and filtered. The filtrate was acidified by citric acid and the white solid was precipitated. It was filtered and washed with water to give the product (2.5 g, yield 48.5%) as a white solid. MS: m/z==258.9 (M+1, ESI+).

Provenance & Evidence