反应详情

5-fluorosalicylic acid (5.15 g.) and 3,5-dichloro-4-hydroxyaniline (5.88 g.) were well mixed to which was added benzene (10 ml.) and N,N-dimethylaniline (4.35 ml.). Then with stirring thionyl chloride (3.3 ml.) was added and refluxed 30 minutes. The resulting solution was evaporated and the residue was dissolved in ethyl acetate and subjected to decolorization with activated charcoal followed by washing with 2 N hydrochloric acid and 2.5% sodium bicarbonate solution. The ethyl acetate was then extracted several times with 2 N sodium carbonate solution and the aqueous extracts were combined and brought to pH 1-2 with hydrochloric acid to give a precipitate which was recrystalized from aqueous acetone to give white needle-like crystals (5.7 g.) of 3,5-dichloro-2',4-dihydroxy-5'-fluorobenzanilide. Yield: 55%. Melting point: 227°-229° C.

1. temperaturerefluxed 30 minutes
2. customThe resulting solution was evaporated
3. dissolutionthe residue was dissolved in ethyl acetate
4. washby washing with 2 N hydrochloric acid and 2.5% sodium bicarbonate solution
5. extractionThe ethyl acetate was then extracted several times with 2 N sodium carbonate solution
6. customto give a precipitate which
7. customwas recrystalized from aqueous acetone