反应详情

温度

30 °C

2 ml of dibromoethane are added to a suspension of 26.73 g (1 mole+10% excess) of magnesium in 250 ml of anhydrous tetrahydrofuran and warmed to about 30° C. to initiate the reaction. Immediately thereafter, 277.5 g (1 mole) of 8-bromo-6-chloro-2,2-dimethyl-4H-1,3-benzodioxin dissolved in 250 ml of tetrahydrofuran are added dropwise thereto in such a manner that the temperature does not exceed 40° C. The addition takes about 150 minutes. The organomagnesium compound is cooled to about 10° C. (partial precipitation) and it is then added to a solution of 338 g (1 mole) of 1-triphenylmethyl-1H-imidazole-4-carboxaldehyde in 2.8 liters of tetrahydrofuran which has previously been cooled to 0° C. During the addition, the temperature of the mixture increases progressively to 20° C. Stirring is continued for 1 hour at this temperature and then 53.5 g (1 mole) of ammonium chloride are added. After stirring for 1 hour, 18 ml of water are added and stirring is maintained for a further hour. The tetrahydrofuran is removed under reduced pressure. The residue is taken up in 5 liters of dichloromethane and washed with 2 liters of water containing 30 g of sodium bisulfite. The aqueous phase is separated and washed with 1 liter of dichloromethane. The organic phases are again washed with water, then dried over anhydrous sodium sulfate and the solvent removed under reduced pressure. The residue is recrystallized from about 4 liters of toluene at 80° C. and filtered hot on Norit. 335.6 g of alpha-(6-chloro-2,2-dimethyl-4H-1,3-benzodioxin-8-yl)-1-triphenylmethyl-1H-imidazole-4-methanol, which contans one molecule of toluene, are thus obtained. M.P.: 120° C. followed by 188° C.

1. customthe reaction
2. additionare added dropwise
3. customdoes not exceed 40° C
4. additionThe addition
5. custom(partial precipitation) and it
6. temperaturehas previously been cooled to 0° C
7. additionDuring the addition
8. temperaturethe temperature of the mixture increases progressively to 20° C
9. waitis continued for 1 hour at this temperature
10. stirringAfter stirring for 1 hour
11. stirringstirring
12. temperatureis maintained for a further hour
13. customThe tetrahydrofuran is removed under reduced pressure
14. washwashed with 2 liters of water containing 30 g of sodium bisulfite
15. customThe aqueous phase is separated
16. washwashed with 1 liter of dichloromethane
17. washThe organic phases are again washed with water
18. dry with materialdried over anhydrous sodium sulfate
19. customthe solvent removed under reduced pressure
20. customThe residue is recrystallized from about 4 liters of toluene at 80° C.
21. filtrationfiltered hot on Norit
22. customare thus obtained
23. customfollowed by 188° C.