反応 #40742

反応方程式

dimethyl carbonate

4,5-dichloro-1-ethyl-2-naphthalen-1-yl-1H-imidazole

n-BuLi

hexane

→

5-chloro-3-ethyl-2-naphthalen-1-yl-3H-imidazole-4-carboxylic acid ethyl ester

溶媒

Water

THF

反応条件

後処理

1. 1
   workup.STIRRINGThe resulting solution is stirred at −78° C. for 30 min
2. 2
   温度warmed to rt slowly
3. 3
   workup.STIRRINGstirred for an additional 60 min at rt
4. 4
   その他to quench
5. 5
   その他the reaction, and THF
6. 6
   その他is evaporated under reduced pressure
7. 7
   抽出The residue is extracted with EtOAc (30 ml×2)
8. 8
   洗浄the combined organic layers are washed with water and brine
9. 9
   乾燥dried over sodium sulfate
10. 10
    濃縮concentrated
11. 11
    その他The crude product is purified through silica gel chromatography (hexanes/EtOAc, from 20:1 to 10:1)

実験手順

To a solution of 4,5-dichloro-1-ethyl-2-naphthalen-1-yl-1H-imidazole (2.87 g, 9.86 mmol) in anhydrous THF (60 ml) at −78° C. under nitrogen is added a solution of n-BuLi in hexane (1.6 M, 6.78 ml, 10.84 mmol, 1.1 eq.) dropwise. The resulting mixture is stirred at −78° C. for 1 hr, followed by the addition of dimethyl carbonate (2.66 g, 29.6 mmol, 3.0 eq.). The resulting solution is stirred at −78° C. for 30 min, warmed to rt slowly, and stirred for an additional 60 min at rt. Water (30 ml) is added to quench the reaction, and THF is evaporated under reduced pressure. The residue is extracted with EtOAc (30 ml×2) and the combined organic layers are washed with water and brine, dried over sodium sulfate, and concentrated. The crude product is purified through silica gel chromatography (hexanes/EtOAc, from 20:1 to 10:1) to give 5-chloro-3-ethyl-2-naphthalen-1-yl-3H-imidazole-4-carboxylic acid ethyl ester. LCMS 315 (M+1).

出典