Reaction #696712

Reaction equation

2-(trichloroacetyl) pyrrole

nitric acid

isopropyl alcohol

→

4-Nitro-2-trichloroacetyl-1-methylpyrrole

Solvents

acetic anhydride

Conditions

Workup

1. 1
   Otherto be used without further purification
2. 2
   Otherequipped with a mechanical stirrer
3. 3
   workup.ADDITIONwas added 440 mL
4. 4
   Otherof 1 hour
5. 5
   Temperatureto warm to room temperature
6. 6
   TemperatureThe mixture was cooled to -30° C.
7. 7
   workup.STIRRINGThe solution was stirred at -20° C. for 30 min during which time a white precipitate forms
8. 8
   workup.WAITto stand for 15 min
9. 9
   Filtrationthe resulting precipitate collected by vacuum filtration

Procedure

To a well stirred solution of trichloroacetyl chloride (1 kg, 5.5 mole) in 1.5 liter ethyl ether in a 12 liter flask was added dropwise over a period of 3 h a solution of N-methylpyrrole (0.45 kg, 5.5 mole) in 1.5 liter anhydrous ethyl ether. The reaction was stirred for an additional 3 hours and quenched by the dropwise addition of a solution of 400 g potassium carbonate in 1.5 liters water. The layers were separated and the ether layer concentrated in vacuo to provide 2-(trichloroacetyl)pyrrole (1.2 kg, 5.1 mol) as a yellow crystalline solid sufficiently pure to be used without further purification. To a cooled (-40° C.) solution of 2-(trichloroacetyl) pyrrole (1.2 kg, 5.1 mol) in acetic anhydride (6 L) in a 12 L flask equipped with a mechanical stirrer was added 440 mL fuming nitric acid over a period of 1 hour while maintaining a temperature of (-40° C.). The reaction was carefully allowed to warm to room temperature and stir an additional 4 h. The mixture was cooled to -30° C., and isopropyl alcohol (6 L) added. The solution was stirred at -20° C. for 30 min during which time a white precipitate forms. The solution was allowed to stand for 15 min and the resulting precipitate collected by vacuum filtration.

Source