Dimethylformamide → [3-(Dimethylamino)-2-(imidazol-2-yl)-allylidene]-dimethylammonium hexafluorophosphate

HRID 1730653Notes

Reaction equation

HRID 1730653 reaction equation
[CH3:1][N:2]([CH3:5])[CH:3]=O.C(Cl)(Cl)=O.[CH3:10][C:11]1[NH:12][CH:13]=[CH:14][N:15]=1.[F:16][P-:17]([F:22])([F:21])([F:20])([F:19])[F:18].[Na+]>C(Cl)(Cl)Cl>[F:16][P-:17]([F:22])([F:21])([F:20])([F:19])[F:18].[CH3:1][N:2]([CH3:5])[CH:3]=[C:10]([C:11]1[NH:12][CH:13]=[CH:14][N:15]=1)[CH:1]=[N+:2]([CH3:5])[CH3:3]

Participants

6

Reactant 4

HCID 6228DimethylformamideHCID 6371PhosgeneHCID 127492-MethylimidazoleHCID 5147921Sodium hexafluorophosphate

Product 1

HCID 86734207[3-(Dimethylamino)-2-(imidazol-2-yl)-allylidene]-dimethylammonium hexafluorophosphate

Reagents, catalysts & solvents 1

HCID 6212ChloroformSolvent

Procedure

The Vilsmeier Haack reagent is prepared using 140 ml. (1.8 mole) of dimethylformamide and 500 ml. of 3N phosgene in chloroform. 2-Methylimidazole (30.8 g., 0.375 mole) is added in portions over one hour maintaining the temperature at or below 10° C. and the mixture is then stirred overnight at ambient temperature. The reaction mixture is poured onto ice (490 g.), shaken and separated. The chloroform solution is extracted with water (35 ml.) and the combined aqueous solutions treated with sodium hexafluorophosphate (63.0 g., 0.375 mole). After filtering, the filtrate is cooled in an ice-bath while sodium carbonate anhydrate (139 g., 1.313 mole) is added in small portions. The crystalline precipitate obtained weighs 50.70 g. (39%) and melts at 185°-187° C. Recrystallization of the crude product from water (5 parts volume by weight) gives purified product melting at 191°-192° C. in the form of colorless crystals.

Workup

  1. customThe Vilsmeier Haack reagent is prepared
  2. temperaturemaintaining the temperature at or below 10° C.
  3. additionThe reaction mixture is poured onto ice (490 g.)
  4. stirringshaken
  5. customseparated
  6. extractionThe chloroform solution is extracted with water (35 ml.)
  7. filtrationAfter filtering
  8. temperaturethe filtrate is cooled in an ice-bath while sodium carbonate anhydrate (139 g., 1.313 mole)
  9. additionis added in small portions
  10. customThe crystalline precipitate obtained
  11. customRecrystallization of the crude product from water (5 parts volume by weight)
  12. customgives
  13. custompurified product melting at 191°-192° C. in the form of colorless crystals

Sources & evidence

ORD record
ord-9badf27b072744f9b5631f810a2c6243
Source dataset
uspto-grants-1976_11
Patent number
US03993656

Reaction notes

Loading…