Reaktion #1945

Reaktionsgleichung

LDA

LDA

hexane

product

nitric acid

ethyl iodide

4-chloro-2-picoline

→

title compound

Ausbeute 60.0%

4-Chloro-2-propyl-pyridine

Ausbeute 60.0%

Lösungsmittel

THF

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGAfter the reaction mixture was stirred at -60° C. for 0.5 hours
2. 2
   Sonstigewas allowed to slowly (1.5 hours)
3. 3
   Temperaturwarm to -30° C
4. 4
   Wascheneluted with 5% methanol in methylene chloride
5. 5
   workup.ADDITIONThe reaction mixture was poured into cold brine
6. 6
   Extraktionthe aqueous mixture was extracted with methylene chloride
7. 7
   ExtraktionThe organic extract
8. 8
   Trocknenwas dried over anhydrous sodium sulfate
9. 9
   Filtrationfiltered
10. 10
    Einengenconcentrated in vacuo
11. 11
    workup.DISTILLATIONThe residue was distilled

Vorschrift

A 1.5M solution of LDA in hexane (100 mL, 150 mmol) was cooled to -60° C. in an isopropyl alcohol/dry ice bath. To the stirred LDA solution, under nitrogen, was added, dropwise over a 0.5 hours period, a solution of 17.466 g (137 mmol) of 4-chloro-2-picoline (the product of Step 1 of Example 58) in 80 mL of dry THF. The reaction mixture was 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 was added, dropwise over a 20 minute period. After the reaction mixture was stirred at -60° C. for 0.5 hours, the cooling bath was allowed to slowly (1.5 hours) warm to -30° C. According to TLC analysis on silica gel eluted with 5% methanol in methylene chloride, the reaction had gone to completion. The reaction mixture was poured into cold brine and the aqueous mixture was extracted with methylene chloride. The organic extract was dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The residue was distilled to afford 12.667 g (60% yield of the title compound, b.p. 77°-80° C. (10 mm Hg).

Quelle