Potassium Permanganate → 2-Chloro-5-methoxy-4-nitrobenzoic acid

Participants

Reaction Conditions

Reaction Steps

A suspension of 1-chloro-4-methoxy-2-methyl-5-nitro-benzene (1.05 g, 5.21 mmol) in a mixture of pyridine and water (1/2, 15 mL) was heated to 97° C. and then potassium permanganate (4.53 g, 28.64 mmol) was added. The reaction mixture was heated at 100° C. for 4 hours; a second aliquot of the mixture pyridine/water (1/1, 10 mL) was added and was followed by potassium permanganate (1 g); the resulting mixture was heated to 100° C. overnight. The hot reaction mixture was filtered through a CELITE™ pad, the filter cake was washed with hot water and the filtrate was acidified, until pH 1, by addition of an aqueous solution of hydrochloric acid (6 M). The resulting mixture was extracted with ethyl acetate; the organic layer was dried over anhydrous sodium sulfate, filtered and evaporated under reduced pressure. The light yellow solid residue (903 mg) was washed twice with a small aliquot of dichloromethane to give 2-chloro-5-methoxy-4-nitro-benzoic acid as an off-white solid without further purifications.

Provenance & Evidence