Reaction #1966

Reaction equation

3,4,5,6-tetrafluoro-2-picoline

LDA

LDA

hexane

ethyl iodide

→

title compound

2-Propyl-3,4,5,6-tetrafluoropyridine

Solvents

brine

THF

THF

Conditions

Workup

1. 1
   workup.STIRRINGAfter the reaction mixture is stirred at -60° C. for 0.5 hours
2. 2
   Otheris allowed to slowly (1.5 hours)
3. 3
   Temperaturewarm to -30° C
4. 4
   Extractionthe aqueous mixture is extracted with methylene chloride
5. 5
   ExtractionThe organic extract
6. 6
   Dryingis dried over anhydrous sodium sulfate
7. 7
   Filtrationfiltered
8. 8
   Concentrationconcentrated in vacuo
9. 9
   workup.DISTILLATIONThe residue is distilled

Procedure

A 1.5M solution of LDA in hexane (100 mL, 150 mmol) is cooled to -60° C. in an isopropyl alcohol/dry ice bath. To the stirred LDA solution, under nitrogen, is added, dropwise over a 0.5 hours period, a solution of 22.617 g (137 mmol) of 3,4,5,6-tetrafluoro-2-picoline, the product of Step 1, in 80 mL of dry THF. The reaction mixture is stirred for 0.5 hours at -60° C. and then a solution of 10.95 mL (137 mmol) of ethyl iodide in 30 mL of dry THF is added, dropwise over a 20 minute period. After the reaction mixture is stirred at -60° C. for 0.5 hours, the cooling bath is allowed to slowly (1.5 hours) warm to -30° C. The reaction mixture is poured into cold brine and the aqueous mixture is extracted with methylene chloride. The organic extract is dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The residue is distilled to afford the title compound.

Source