Reaction #586105

Reaction equation

2-methyl-3-(trimethylsilyloxy)cyclopent-2-enone

ammonia

n-butyllithium

hydrochloric acid

8-bromoquinoline

→

2-methyl-3-(8-quinolyl)cyclopent-2-enone

Yield 74.9%

Solvents

tetrahydrofuran

Conditions

Workup

1. 1
   workup.STIRRINGThe mixture was stirred for a further 15 minutes
2. 2
   workup.STIRRINGwhile stirring
3. 3
   Temperatureto warm to room temperature
4. 4
   workup.STIRRINGwhile stirring
5. 5
   workup.STIRRINGwas stirred for a further one hour
6. 6
   Otherthe mixture obtained in this way
7. 7
   Temperaturewas refluxed for 3 hours
8. 8
   Temperatureto cool to room temperature
9. 9
   workup.STIRRINGwhile stirring
10. 10
    OtherThe aqueous phase was then separated off from the organic phase
11. 11
    Extractionthe aqueous phase was extracted twice with diethyl ether
12. 12
    Dryingdried over magnesium sulfate
13. 13
    Filtrationfiltered
14. 14
    workup.DISTILLATIONthe solvent was distilled off
15. 15
    OtherThe residue obtained in this way
16. 16
    workup.DISTILLATIONwas distilled at 119-139° C.

Procedure

A mixture of 38.7 g (186 mmol) of 8-bromoquinoline in 250 ml of tetrahydrofuran was cooled to −80° C. and 74.4 ml of n-butyllithium (2.5 M in hexane, 186 mmol) were subsequently added while stirring. The mixture was stirred for a further 15 minutes and, while stirring, 49.9 g (186 mmol) of 2-methyl-3-(trimethylsilyloxy)cyclopent-2-enone were added. The mixture was allowed to warm to room temperature while stirring and was stirred for a further one hour. The reaction mixture was then hydrolyzed by means of a mixture of 40 g of ice and 30 ml of concentrated hydrochloric acid and the mixture obtained in this way was refluxed for 3 hours. The mixture was allowed to cool to room temperature while stirring and ammonia solution was added until the pH was 12. The aqueous phase was then separated off from the organic phase and the aqueous phase was extracted twice with diethyl ether. The organic phases were combined, dried over magnesium sulfate, filtered and the solvent was distilled off. The residue obtained in this way was distilled at 119-139° C. and 2×10−2 mbar to give 31.1 g (139.3 mmol, 74.9%) of 2-methyl-3-(8-quinolyl)cyclopent-2-enone.

Source