Reaktion #90356

Reaktionsgleichung

water

2-chloropyridine

LDA

water

acetaldehyde

→

1-(2-chloropyridin-3-yl)ethanol

Ausbeute 38.1%

Lösungsmittel

THF

THF

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGThe solution was stirred at −78° C. for another 2 h
2. 2
   Sonstigeto rise to −40° C
3. 3
   Sonstigereached −10° C.
4. 4
   ExtraktionThe solution was extracted with ethyl ether (3×100 mL)
5. 5
   TrocknenThe combined organic phase was dried over MgSO4
6. 6
   Filtrationfiltered
7. 7
   Sonstigeevaporated under reduced pressure
8. 8
   Sonstigeto get a brown viscous residue
9. 9
   SonstigeThe crude product was purified on a flash silica gel column (1:1 DCM:hexane→100% DCM)

Vorschrift

A solution of 2-chloropyridine (I) (9.39 mL, 0.1 mol) in anhydrous THF (50 mL) was added slowly to a solution of LDA (2.0 M solution in THF/hexane/ethylbenzene, 50 mL, 0.1 mol) in THF (200 mL) stirred at −78° C. under nitrogen. The stirring was continued at −78° C. for an additional 3 h before adding acetaldehyde (6.17 mL, 0.110 mol). The solution was stirred at −78° C. for another 2 h before allowing the temperature to rise to −40° C. A solution of water (4 mL) in THF (40 mL) was added slowly to the solution. When the temperature reached −10° C., additional water (200 mL) was added to the solution. The solution was extracted with ethyl ether (3×100 mL). The combined organic phase was dried over MgSO4, filtered and evaporated under reduced pressure to get a brown viscous residue. The crude product was purified on a flash silica gel column (1:1 DCM:hexane→100% DCM) to produce 1-(2-chloropyridin-3-yl)ethanol (II) as a brown viscous oil (6 g, 38.1 mmol, 38% yield). 1H NMR (CDCl3) δ ppm 1.52 (d, J=6.41 Hz, 3H), 2.51 (bs, 1H), 5.24 (m, 1H), 7.28 (m, 1H), 7.97 (dd, J=7.72, 1.70, 1H), 8.27 (dd, J=7.72, 1.79, 1H).

Quelle