Reaction #2161247

Reaction equation

1-benzyl-1H-imidazole

triethylamine

ethyl chloroformate

→

Ethyl 1-benzyl-1H-imidazole-2-carboxylate

Solvents

acetonitrile

Conditions

Workup

1. 1
   TemperatureAfter warming to 15 to 20° C.
2. 2
   workup.STIRRINGthe reaction mixture is stirred for 18 h
3. 3
   Concentrationconcentrated in vacuo
4. 4
   workup.ADDITIONWater, a saturated sodium chloride solution and a saturated sodium bicarbonate solution are added to the residue
5. 5
   Extractionthe mixture is extracted three times with ethyl acetate
6. 6
   WashThe combined organic phases are washed with a saturated sodium chloride solution
7. 7
   Dryingafter drying with magnesium sulfate
8. 8
   Concentrationconcentrated in vacuo
9. 9
   workup.DISTILLATIONThe residue is subjected to a fractional distillation under high vacuum (boiling point=173 to 181° C., pressure=1.7 to 1.2 mbar)

Procedure

148 g (936 mmol) of 1-benzyl-1H-imidazole are suspended in 480 ml of acetonitrile and, at −20° C., 120 ml (87.1 g; 860 mmol) of triethylamine are added. Over a period of 15 minutes, 211.2 ml (239 g; 2208 mmol) of ethyl chloroformate are then added dropwise. The reaction mixture is stirred at −20° C. for 10 minutes. After warming to 15 to 20° C., the reaction mixture is stirred for 18 h and then concentrated in vacuo. Water, a saturated sodium chloride solution and a saturated sodium bicarbonate solution are added to the residue, and the mixture is extracted three times with ethyl acetate. The combined organic phases are washed with a saturated sodium chloride solution and, after drying with magnesium sulfate, concentrated in vacuo. The residue is subjected to a fractional distillation under high vacuum (boiling point=173 to 181° C., pressure=1.7 to 1.2 mbar).

Source