Reaction #329560

Reaction equation

n-butyl lithium

ammonium chloride

( 2 )

4-(tert-Butyldiphenylsilyloxymethyl)-1-(2-fluoroethyl)-1H-imidazole

N-methoxy-N-methylacetamide

→

title compound

1-[4-(tert-Butyldiphenylsilyloxymethyl)-1-vinyl-1H-imidazol-2-yl]ethanone

1-[4-(tert-butyldiphenylsilyloxymethyl)-1-(2-fluoroethyl)-1H-imidazol-2-yl)ethanone

Solvents

THF

Conditions

Workup

1. 1
   workup.STIRRINGby stirring at the same temperature for 30 minutes
2. 2
   workup.STIRRINGstirring
3. 3
   Otherwas gradually brought back to room temperature
4. 4
   Otherto terminate
5. 5
   Otherthe reaction
6. 6
   Extractionfollowed by extraction with ethyl acetate
7. 7
   WashThe extract was washed with saturated brine
8. 8
   Dryingdried over anhydrous sodium sulfate
9. 9
   workup.DISTILLATIONsubsequently the solvent was distilled off under reduced pressure
10. 10
    OtherThe resulting residue was purified by flash chromatography (ethyl acetate/hexane=4%→40%)

Procedure

The compound (5.35 g) obtained in (2) was dissolved in THF (200 mL), and cooled to −78° C. while stirring under nitrogen stream. To the present solution was added dropwise n-butyl lithium (2.76 M hexane solution, 7.60 mL), followed by stirring at the same temperature for 30 minutes. Then, N-methoxy-N-methylacetamide (2.91 mL) was added, and stirring was continued for 4 hours while the temperature was gradually brought back to room temperature. A saturated aqueous ammonium chloride solution was added to the reaction solution to terminate the reaction, followed by extraction with ethyl acetate. The extract was washed with saturated brine, dried over anhydrous sodium sulfate, and subsequently the solvent was distilled off under reduced pressure. The resulting residue was purified by flash chromatography (ethyl acetate/hexane=4%→40%) using silica gel column (product name: Hi-Flash Column 3 L, manufactured by Yamazen Corporation) to afford the title compound (1.48 g) and 1-[4-(tert-butyldiphenylsilyloxymethyl)-1-(2-fluoroethyl)-1H-imidazol-2-yl)ethanone (3.91 g).

Source