Potassium Fluoride → 2-Chloro-4,5-difluorobenzoic acid

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Reaction Conditions

Reaction Steps

The combined benzoic acids made in each of Examples 3, 11 and 12 (consisting of compounds 5 and 6 in a ratio of about 2:1) were converted to the corresponding acid chlorides as in Example 4. The acid chlorides (2 g, 8.4 mmol) were dissolved in 4 ml of tetramethylenesulfone and treated with spray-dried KF (2.0 g, 34.5 mmol). The mixture was heated at 150° C. under nitrogen for 3 hours and the product distilled at 70°-75° C./15 mm. The acid fluoride collected was hydrolyzed with water and the product was dried in vacuum to give pure compound 8 as the only product (0.4 g, 24%).

Provenance & Evidence