反応 #44326

反応方程式

1-bromo-2,4-difluorobenzene

2-bromopyridine

hexane

n-butyllithium

→

2-(2,4-difluorophenyl)pyridine

収率 63.0%

溶媒

tetrahydrofuran

tetrahydrofuran

反応条件

後処理

1. 1
   その他over 30 minutes
2. 2
   その他was slowly elevated to 0° C.
3. 3
   温度under reflux
4. 4
   workup.ADDITION200 ml of saturated saline was added to the reaction mixture
5. 5
   抽出followed by extraction of the reaction mixture with diethyl ether
6. 6
   その他After drying
7. 7
   濃縮the extract, concentration and purification by column chromatography (silica gel; chloroform/hexane (1/1: volume ratio))

実験手順

That is, under argon stream, 8.69 g (55.0 mmol) of 2-bromopyridine was dissolved in 200 ml of dry tetrahydrofuran and cooled to −78° C. To this was dripped 38.7 ml (61.9 mmol) of a 1.6 M hexane solution of n-butyllithium over 30 minutes. After completion of the dripping, further a solution of 7.5 g (55.0 mmol) of zinc chloride in 50 ml of dry tetrahydrofuran was dripped over 30 minutes. After completion of the dripping, the temperature of the mixture was slowly elevated to 0° C. and 9.65 g (55.0 mmol) of 1-bromo-2,4-difluorobenzene and 2.31 g (2.0 mmol) of tetrakis(triphenylphosphine)palladium (0) were added thereto. The mixture was stirred for 6 hours under reflux and then 200 ml of saturated saline was added to the reaction mixture, followed by extraction of the reaction mixture with diethyl ether. After drying the extract, concentration and purification by column chromatography (silica gel; chloroform/hexane (1/1: volume ratio)) afforded 6.00 g (31.4 mmol) of 2-(2,4-difluorophenyl)pyridine as colorless transparent oil. Yield: 63%. Identification was performed by elementary analysis of 1H-NMR and elementary analysis of C, H and N.

出典