反应详情

温度

95 °C

A mixture of 500 g methyl 4,5-dimethoxy-2-nitro-benzoate and 625 g potassium hydroxide in 2300 ml of water is heated to 95° C. for 18.5 h. After cooling, the mixture is filtered clear and the filtrate is diluted with 3 l water. The solution is combined with 950 ml acetic acid and after 1 h the precipitate is filtered off. The precipitate is suspended in 3250 ml ethyl acetate and then 100 ml of water and 200 ml 12N hydrochloric acid are added. After 1.5 h the phases are separated and the aqueous phase is extracted with 700 ml ethyl acetate. The combined organic phases are dried on magnesium sulphate and after filtration they are evaporated down. The mixture is evaporated again with 200 ml methylcyclohexane. The residue is refluxed together with 1600 ml of methanol and 100 ml conc. sulphuric acid for 16.5 h. The mixture is evaporated down until crystallisation begins. 1000 ml of water are added and the mixture is stirred until a homogeneous suspension is obtained. The precipitate is filtered off, washed with 500 ml of water and suspended in 1000 ml of water. After 1.5 h stirring the precipitate is filtered off and washed with 500 ml of water. After the filter cake is dried, 364 g product are obtained.

1. temperatureAfter cooling
2. filtrationthe mixture is filtered clear
3. additionthe filtrate is diluted with 3 l water
4. filtrationthe precipitate is filtered off
5. addition100 ml of water and 200 ml 12N hydrochloric acid are added
6. customAfter 1.5 h the phases are separated
7. extractionthe aqueous phase is extracted with 700 ml ethyl acetate
8. customThe combined organic phases are dried on magnesium sulphate
9. filtrationafter filtration they
10. customare evaporated down
11. customThe mixture is evaporated again with 200 ml methylcyclohexane
12. temperatureThe residue is refluxed together with 1600 ml of methanol and 100 ml conc. sulphuric acid for 16.5 h
13. customThe mixture is evaporated down until crystallisation
14. addition1000 ml of water are added
15. customis obtained
16. filtrationThe precipitate is filtered off
17. washwashed with 500 ml of water
18. stirringAfter 1.5 h stirring the precipitate
19. filtrationis filtered off
20. washwashed with 500 ml of water
21. customAfter the filter cake is dried