Reaktion #1998159

Reaktionsgleichung

ammonium chloride

n-butyllithium

2,6-dibromopyridine

tert-butyl 4-oxopiperidine-1-carboxylate

→

tert-Butyl 4-(6-bromopyridin-2-yl)-4-hydroxypiperidine-1-carboxylate

Lösungsmittel

dichloromethane

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGThe mixture is stirred at room temperature for 20 minutes
2. 2
   Sonstigethe aqueous phase is removed
3. 3
   ExtraktionAfter the aqueous phase has been extracted with dichloromethane
4. 4
   Trocknenthe combined organic phases are dried over sodium sulphate
5. 5
   Einengenconcentrated under reduced pressure
6. 6
   SonstigeThe residue is purified by chromatography

Vorschrift

To a solution of 2,6-dibromopyridine (34 g) in dichloromethane (740 ml) is added dropwise, at −78° C. under argon, n-butyllithium (1.6 M in tetrahydrofuran, 100 ml). The reaction mixture is stirred at −78° C. for 20 minutes and then tert-butyl 4-oxopiperidine-1-carboxylate is added. The mixture is stirred at room temperature for 20 minutes. The reaction mixture is subsequently admixed with saturated ammonium chloride solution at −30° C. and the aqueous phase is removed. After the aqueous phase has been extracted with dichloromethane, the combined organic phases are dried over sodium sulphate and concentrated under reduced pressure. The residue is purified by chromatography. This gives tert-butyl 4-(6-bromopyridin-2-yl)-4-hydroxypiperidine-1-carboxylate (60 g).

Quelle