Carbon Dioxide → 2,3,5,6-Tetrafluorobenzoic Acid

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

n-Butyllithium (2.7M solution in n-hexane, 148 cm3) was added dropwise over a period of one hour to a stirred solution of 2,3,5,6-tetrafluorobenzene (60 g) in dry tetrahydrofuran (200 cm3) maintained at -70° C. under a nitrogen atmosphere, after which the mixture was stirred at -70° C. for a further one hour. Carbon dioxide gas was passed into the mixture over a period of 4 hours during which time the temperature was allowed to warm up to the ambient value (ca. 22° C.). After adding water and acidifying with dilute hydrochloric acid, the mixture was extracted with diethyl ether and the extracts dried over anhydrous magnesium sulphate. The product was obtained by removal of the solvent by evaporation under reduced pressure to give 2,3,5,6-tetrafluorobenzoic acid (42.5 g), mp. 152°-154° C.

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