Reaktion #1710031

Reaktionsgleichung

Triisopropyl borate

potassium carbonate

2,5-dibromopyridine

n-Butyllithium

N1,N1,N2,N2-tetramethylethane-1,2-diamine

tert-butyl pyridin-2-ylcarbamate

→

title compound

Ausbeute 50.0%

5-bromo-2,3′-bipyridin-2′-amine

Ausbeute 50.0%

Lösungsmittel

toluene

MeOH

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGThe mixture was stirred at 0° C. under N2 for 30 min
2. 2
   SonstigeThe mixture was quenched with sat. NH4Cl aq. at 0° C.
3. 3
   workup.ADDITIONadded with Et2O
4. 4
   Sonstigeto give a yellow precipitate (11.68 g, wet)
5. 5
   workup.ADDITIONNH silica gel was added
6. 6
   Einengenthe mixture was concentrated in vacuo
7. 7
   SonstigeThe residue was purified by column chromatography (NH silica gel, eluted with EtOAc in hexane)

Vorschrift

n-Butyllithium (1.6 M in hexane, 48.3 mL) was added dropwise to a solution of N1,N1,N2,N2-tetramethylethane-1,2-diamine (8.08 g) and tert-butyl pyridin-2-ylcarbamate (5 g) in THF (dry) (50 mL) at −78° C. The mixture was stirred at 0° C. under N2 for 2 hr. Triisopropyl borate (16.95 g) was added to the mixture at −78° C. The mixture was stirred at 0° C. under N2 for 30 min. The mixture was quenched with sat. NH4Cl aq. at 0° C. and added with Et2O to give a yellow precipitate (11.68 g, wet). A mixture of potassium carbonate (438 mg), tetrakis(triphenylphosphine)palladium(0) (61.0 mg), 2,5-dibromopyridine (250 mg) and the precipitate (250 mg) in toluene (10 mL) and MeOH (5 mL) was stirred at 80° C. under N2 overnight. NH silica gel was added and the mixture was concentrated in vacuo. The residue was purified by column chromatography (NH silica gel, eluted with EtOAc in hexane) to give the title compound (132 mg) as a yellow solid.

Quelle