Diflunisal → 2',4'-Difluoro-4-hydroxy-5-iodo-1,1'-biphenyl-3-carboxylic acid

Beteiligte Stoffe

Reaktionsschritte

A mixture of 20.6 g of thallium trifluoroacetate (TTFA, 31.9 mmol) and trifluoroacetic acid (TFA, 50 ml) was stirred in a flask until the TTFA dissolved. This solution was added at room temperature to a flask containing 51 g (205 mmol) of diflunisal and it was stirred for 30 min. A solution of potassium iodide (KI, 40.9 g, 245.6 mmol) in 120 ml of water was slowly added to the mixture. After the reaction finished, the product was worked up. First, sodium metabisulphite (NaS2O5, 5.01 g, 26.4 mmol) was added to reduce the species of TI (III) to TI (I), and then a solution of sodium hydroxide was added to neutralize the TFA. It was extracted with dichloromethane and the organic phase was washed with water and dried over magnesium sulphate. The solvent was evaporated at low pressure and a crude was obtained of 96% purity, which was purified by chromatography on a silica gel column using the appropriate eluents.

Herkunft & Nachweise