反应详情

8.08 g (202 mmol) of 60% sodium hydride was added to 30 ml of tetrahydrofuran, and while cooling on a freezing mixture, 60 ml of tetrahydrofuran solution containing 32.0 g (200 mmol) of diethyl malonate was dropped to the solution below 20° C. over 1 hour, then the solution was stirred for 1 hour. 60 ml of Tetrahydrofuran solution containing 19.2 g (100 mmol) of 2,3-dichloronitrobenzene was dropped to the solution below 10° C. over 10 minutes. After the solution was stirred for 3.5 hours at room temperature, it was heated at reflux for 48 hours. 18 ml of acetic acid was added to the solution, and the solvent was removed by distillation. The solution was extracted over 200 ml of chloroform, and after drying over magnesium sulfate, the solvent was removed by distillation. To the residue, 30 ml of 4N hydrochloric acid and 25 ml of acetic acid were added, and the solution was heated at reflux for 24 hours. After air-cooling, the deposited crystals were filtered off and washed with water, and they were dissolved in 250 ml of ethyl acetate. The filtrate was extracted with 250 ml of ethyl acetate. The organic layers were combined, and after drying over magnesium sulfate, the solvent was removed by distillation. The crystals were washed with n-hexane to obtain 6.78 g of the subject compound (137) in a 31% yield.

1. additionwas dropped to the solution below 20° C. over 1 hour
2. additionwas dropped to the solution below 10° C. over 10 minutes
3. stirringAfter the solution was stirred for 3.5 hours at room temperature
4. temperatureit was heated
5. temperatureat reflux for 48 hours
6. customthe solvent was removed by distillation
7. extractionThe solution was extracted over 200 ml of chloroform
8. dry with materialafter drying over magnesium sulfate
9. customthe solvent was removed by distillation
10. additionTo the residue, 30 ml of 4N hydrochloric acid and 25 ml of acetic acid were added
11. temperaturethe solution was heated
12. temperatureat reflux for 24 hours
13. temperatureAfter air-cooling
14. filtrationthe deposited crystals were filtered off
15. washwashed with water, and they
16. dissolutionwere dissolved in 250 ml of ethyl acetate
17. extractionThe filtrate was extracted with 250 ml of ethyl acetate
18. dry with materialafter drying over magnesium sulfate
19. customthe solvent was removed by distillation
20. washThe crystals were washed with n-hexane