Reaction #42260

Reaction equation

potassium hydroxide

4,4′-dimethylbenzophenone

hydrochloric acid

3-tert-butyl-1-methyl-cyclopentadiene

→

aimed compound

3-tert-butyl-1-methyl-6,6-di-(p-tolyl)fulvene

Solvents

dimethoxy ethane

dimethoxy ethane

Conditions

Workup

1. 1
   OtherIn a 200 ml three-necked flask equipped with a magnetic stirrer chip and three-way cock
2. 2
   workup.ADDITIONwere added in a nitrogen atmosphere
3. 3
   Temperatureunder reflux for 2 hr
4. 4
   OtherTo the reaction solution, a solution prepared
5. 5
   workup.ADDITIONwas gradually added
6. 6
   workup.STIRRINGstirred
7. 7
   Temperatureunder reflux for 3 days
8. 8
   workup.STIRRINGstirred at room temperature for some time
9. 9
   OtherThe organic phase was separated
10. 10
    workup.ADDITIONby adding diethyl ether
11. 11
    Washwashed with a saturated sodium bicarbonate aqueous solution, water and saturated brine
12. 12
    DryingThe organic phase was dried with anhydrous magnesium sulfate
13. 13
    Filtrationthe drying agent was filtered off
14. 14
    workup.DISTILLATIONthe solvent was distilled off from the filtrate under reduced pressure
15. 15
    Otherto give a dark red liquid
16. 16
    OtherThe liquid was purified by a column chromatography
17. 17
    workup.DISTILLATIONthe developing solvent was distilled off under reduced pressure

Procedure

In a 200 ml three-necked flask equipped with a magnetic stirrer chip and three-way cock thoroughly purged with nitrogen, 1.56 g of powdery potassium hydroxide (27.8 mmol) and 100 ml of dehydrated dimethoxy ethane were added in a nitrogen atmosphere. To the suspension, 2.46 g of 3-tert-butyl-1-methyl-cyclopentadiene (18.0 mmol) was gradually added dropwise at room temperature and stirred under reflux for 2 hr. To the reaction solution, a solution prepared by dissolving 3.99 g of 4,4′-dimethylbenzophenone (19.0 mmol) in 40 ml of dehydrated dimethoxy ethane was gradually added and stirred under reflux for 3 days. To the reaction mixture, 50 ml of a hydrochloric acid aqueous solution (1N) was gradually added dropwise in an ice bath, and stirred at room temperature for some time. The organic phase was separated by adding diethyl ether and washed with a saturated sodium bicarbonate aqueous solution, water and saturated brine. The organic phase was dried with anhydrous magnesium sulfate, and thereafter the drying agent was filtered off and the solvent was distilled off from the filtrate under reduced pressure to give a dark red liquid. The liquid was purified by a column chromatography using 170 g of silica gel (developing solvent: n-hexane) and the developing solvent was distilled off under reduced pressure, and thereby the aimed compound was obtained in an amount of 2.55 g (7.76 mmol) as a red solid (yield: 43%).

Source