反应详情

温度

10 °C

A solution of 69.65 g of potassium permanganate in 730 cm3 of water is added in the course of 1 hour, while keeping the temperature between 10° and 14° C., to a stirred suspension, cooled to about 10° C., of 45.7 g of 2-chloro-6,7,8-trifluoro-3-formyl-1,4-dihydroquinoline in 585 cm3 of N potassium hydroxide solution. The mixture is stirred for a further 30 minutes at about 10° C. 12 g of sodium dithionite are added and the mixture is stirred for 10 minutes at a temperature close to 10° C. and filtered through diatomaceous silica and the filter cake is washed with 3 times 400 cm3 of water. The filtrate and the washings are combined and 70 cm3 of a 35% aqueous solution of hydrochloric acid are added. The precipitate formed is extracted with 3 times 500 cm3 of ethyl acetate. The combined organic extracts are dried over magnesium sulphate, filtered and concentrated under reduced pressure (20 kPa) at 50° C. The residue is taken up in a mixture of 100 cm3 of diethyl ether and 100 cm3 of diisopropyl ether, drained and washed with 100 cm3 of the same mixture. 46.43 g of 2-chloro-6,7,8-trifluoroquinoline-3-carboxylic acid are obtained in the form of a colourless solid which decomposes at 225°-230° C. and which is used for the subsequent steps without further purification.

1. customthe temperature between 10° and 14° C.
2. stirringthe mixture is stirred for 10 minutes at a temperature
3. customclose to 10° C.
4. filtrationfiltered through diatomaceous silica
5. washthe filter cake is washed with 3 times 400 cm3 of water
6. addition70 cm3 of a 35% aqueous solution of hydrochloric acid are added
7. customThe precipitate formed
8. extractionis extracted with 3 times 500 cm3 of ethyl acetate
9. dry with materialThe combined organic extracts are dried over magnesium sulphate
10. filtrationfiltered
11. concentrationconcentrated under reduced pressure (20 kPa) at 50° C
12. additionThe residue is taken up in a mixture of 100 cm3 of diethyl ether and 100 cm3 of diisopropyl ether
13. washwashed with 100 cm3 of the same mixture