Carbon Tetrachloride → 2,4-Difluorobenzoyl chloride

HRID 359026Notes

Reaction equation

HRID 359026 reaction equation
C1(NN[C:9](=[O:18])[C:10]2[CH:15]=[CH:14][C:13]([F:16])=[CH:12][C:11]=2[F:17])C=CC=CC=1.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.C(#N)C.C(Cl)(Cl)(Cl)[Cl:42]>>[Cl:42][C:9](=[O:18])[C:10]1[CH:15]=[CH:14][C:13]([F:16])=[CH:12][C:11]=1[F:17]

Participants

5

Reactant 4

HCID 5943Carbon TetrachlorideHCID 6342AcetonitrileHCID 11776TriphenylphosphineHCID 151170482,4-Difluorobenzoic acid, 2-phenylhydrazide

Product 1

HCID 5880812,4-Difluorobenzoyl chlorideYield 89%

Procedure

To a stirred mixture, under nitrogen, of 49.6 g of 2,4-difluorobenzoic acid, 2-phenylhydrazide, 64.3 g of triphenylphosphine, and 500 ml of anhydrous acetonitrile was added 19.3 ml of carbon tetrachloride. The reaction mixture was stirred at ambient temperature for about 16 hours, concentrated, and extracted with diethyl ether (3×). The diethyl ether extract was filtered and concentrated to a residue, which was flash chromatographed on silica gel, eluting first with ethyl acetate-hexane and, in a subsequent run, with ethyl acetate alone. Concentration of the appropriate fractions yielded 47.5 g (89%) of α-chloro-2,4-difluorobenzaldehyde, phenylhydrazone.

Workup

  1. concentrationconcentrated
  2. extractionextracted with diethyl ether (3×)
  3. extractionThe diethyl ether extract
  4. filtrationwas filtered
  5. concentrationconcentrated to a residue, which
  6. customchromatographed on silica gel
  7. washeluting first with ethyl acetate-hexane and, in a subsequent run, with ethyl acetate alone

Sources & evidence

ORD record
ord-ec22d4b4842c498d9e195d5fe6719549
Source dataset
uspto-grants-1991_03
Patent number
US04999356

Reaction notes

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