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

Temperature

97 °C

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.

1. temperatureThe reaction mixture was heated at 100° C. for 4 hours
2. temperaturethe resulting mixture was heated to 100° C. overnight
3. filtrationThe hot reaction mixture was filtered through a CELITE™ pad
4. washthe filter cake was washed with hot water
5. additionthe filtrate was acidified, until pH 1, by addition of an aqueous solution of hydrochloric acid (6 M)
6. extractionThe resulting mixture was extracted with ethyl acetate
7. dry with materialthe organic layer was dried over anhydrous sodium sulfate
8. filtrationfiltered
9. customevaporated under reduced pressure
10. washThe light yellow solid residue (903 mg) was washed twice with a small aliquot of dichloromethane

ORD record

ord-8f27cd0b951c415da1c7de106ef5fff9

Source dataset

uspto-grants-2016_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09255110B2