反应详情

5-Chloro-2-nitro-benzoic acid (compound A′) (10.0 g) was dissolved in ethanol (100 ml). Thionyl chloride (20 ml) was added dropwise to the solution at 0° C., and the mixture was then heated under reflux with stirring for 48 hr. After the completion of the reaction, the reaction solution was concentrated under the reduced pressure. Distilled water was added to the residue, and the mixture was neutralized with a saturated aqueous sodium hydrogencarbonate solution under ice cooling. The cooled solution was subjected to separatory extraction with ethyl acetate. The organic layer was dried over sodium sulfate and was then concentrated under the reduced pressure. The residue was purified by column chromatography eluted with a chloroform-methanol system to give 5-chloro-2-nitro-benzoic acid ethyl ester as a useful intermediate (11.0 g, yield 97%).

1. temperaturethe mixture was then heated
2. temperatureunder reflux
3. customAfter the completion of the reaction
4. concentrationthe reaction solution was concentrated under the reduced pressure
5. additionDistilled water was added to the residue
6. extractionThe cooled solution was subjected to separatory extraction with ethyl acetate
7. dry with materialThe organic layer was dried over sodium sulfate
8. concentrationwas then concentrated under the reduced pressure
9. customThe residue was purified by column chromatography
10. washeluted with a chloroform-methanol system