反应详情

A solution of 305 g of crude diethyl 10,11-dihydro-5H-dibenzo[a,d]cycloheptene-5-malonate and 138 g of potassium hydroxide in 1.5 l of ethanol and 400 ml of water is heated to boiling under reflux for 1.5 hours while stirring and subsequently evaporated in vacuo. The residue obtained is partitioned between 1 l of ether and 1 l of ice-water. The aqueous, alkaline phase is extracted further with 500 ml of ether, made acid with about 220 ml of concentrated hydrochloric acid while cooling with ice and extracted with 2 l of ether. The ethereal phase is washed three times with 500 ml of water each time and the aqueous washings are back-extracted with 1 l of ether. The combined ether extracts are washed for an additional three to four times with saturated sodium chloride solution, dried over magnesium sulfate and concentrated to a volume of about 400 ml. After dilution with 300 ml of petroleum ether, the clear solution obtained is cooled in an ice-bath and left to stand at 4° overnight. The crystallized-out material is removed by filtration under suction while back-washing with petroleum ether and dried at 50° in a vacuum drying oven. There is obtained 10,11-dihydro-5H-dibenzo[a,d]cycloheptene-5-malonic acid of melting point 183° (with decarboxylation).

1. temperatureunder reflux for 1.5 hours
2. customsubsequently evaporated in vacuo
3. customThe residue obtained
4. customis partitioned between 1 l of ether and 1 l of ice-water
5. extractionThe aqueous, alkaline phase is extracted further with 500 ml of ether
6. temperaturewhile cooling with ice
7. extractionextracted with 2 l of ether
8. washThe ethereal phase is washed three times with 500 ml of water each time
9. extractionthe aqueous washings are back-extracted with 1 l of ether
10. washThe combined ether extracts are washed for an additional three to four times with saturated sodium chloride solution
11. dry with materialdried over magnesium sulfate
12. concentrationconcentrated to a volume of about 400 ml
13. customAfter dilution with 300 ml of petroleum ether, the clear solution obtained
14. temperatureis cooled in an ice-bath
15. waitleft
16. customThe crystallized-out material is removed by filtration under suction
17. washwhile back-washing with petroleum ether
18. customdried at 50° in a vacuum
19. customdrying oven