Reaktion #2719

Reaktionsgleichung

2-methylthiophene

n-BuLi

2,2-dimethyl-6-bromo-thiochroman-4-one

Compound M

2,2-dimethyl-6-bromo-thiochroman-4-one

→

title compound

2,2-Dimethyl-4(2-methyl-thien-5-yl)-6-bromo-thiochrom-3-ene

Lösungsmittel

THF

hexane

THF

ether

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigewas recooled to -78° C.
2. 2
   workup.STIRRINGThe mixture was stirred for 16 hours at ambient temperature
3. 3
   Waschenwashed with water (10 mL), brine (10 mL)
4. 4
   Sonstigedried
5. 5
   Sonstigethe solvent was removed by evaporation
6. 6
   SonstigeThe product was seperated by column chromatography
7. 7
   workup.DISSOLUTIONwas dissolved in dichloromethane (5 mL)
8. 8
   workup.ADDITIONTo this solution p-TSA (5 mg) was added
9. 9
   workup.STIRRINGthe mixture was stirred at ambient temperature for 5 min
10. 10
    SonstigeThe reaction was quenched with 10% NaHCO3 (3 mL)
11. 11
    Waschenwashed with brine (5 mL)
12. 12
    Sonstigedried
13. 13
    Sonstigethe solvent was removed by distillation
14. 14
    SonstigeThe residual crude material was purified by column chromatography

Vorschrift

To a cold (-78° C.) solution of 2-methylthiophene (1.2 g, 12.2 mmol) in THF (8 mL) was added n-BuLi in hexane (1.6M, 8.5 mL). The mixture was warmed to ambient temperature over 30 minutes. with stirring. The mixture was recooled to -78° C. and a solution of 2,2-dimethyl-6-bromo-thiochroman-4-one (Compound M, 1.4 g, 5.2 mmol) in THF (10 mL) was added. The mixture was stirred for 16 hours at ambient temperature. Then the reaction mixture was diluted with ether (125 mL), washed with water (10 mL), brine (10 mL) dried and the solvent was removed by evaporation. The product was seperated by column chromatography and was dissolved in dichloromethane (5 mL). To this solution p-TSA (5 mg) was added and the mixture was stirred at ambient temperature for 5 min. The reaction was quenched with 10% NaHCO3 (3 mL), washed with brine (5 mL), dried and the solvent was removed by distillation. The residual crude material was purified by column chromatography to obtain the title compound as a pale yellow oil.

Quelle