Sulfuric Acid → 2,6-Difluorobenzaldehyde

HRID 434862Notes

Reaction equation

HRID 434862 reaction equation
[F:1][C:2]1[CH:7]=[CH:6][CH:5]=[C:4]([F:8])[CH:3]=1.C([Li])CCC.CN([CH:22]=[O:23])C1C=CC=CC=1.S(=O)(=O)(O)O>O1CCCC1>[F:1][C:2]1[CH:7]=[CH:6][CH:5]=[C:4]([F:8])[C:3]=1[CH:22]=[O:23]

Participants

6

Reactant 4

HCID 1118Sulfuric AcidHCID 97411,3-DifluorobenzeneHCID 66737N-MethylformanilideHCID 178418339Butyllithium

Product 1

HCID 1362842,6-DifluorobenzaldehydeYield 58.2%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Conditions

Temperature
-50 °C

Procedure

1,3-Difluorobenzene (25 g., 0.22 mole) was dissolved in 150 ml. of tetrahydrofuran and cooled to -50° C. Butyl lithium (99 ml. of 2.3 M in hexane, 0.228 mole) was added over 20 minutes, maintaining the temperature at -50° C. After 1.5 hours of stirring at the same temperature, N-methylformanilide (29.7 g., 0.22 mole) in 50 ml. of tetrahydrofuran was added over 20 minutes at -50° C. After an additional 1.5 hours of stirring at -50° C., the reaction mixture was poured slowly into 1 liter of cold 1 N sulfuric acid, and extracted with three portions of ether. The combined organic extracts were washed with brine, dried over anhydrous magnesium sulfate, filtered and concentrated to an oil. The oil was distilled. Middle cuts were combined to yield 2,6-difluorobenzaldehyde (18.2 g., 58%; b.p. 72°-74°/12 mm.).

Workup

  1. extractionextracted with three portions of ether
  2. washThe combined organic extracts were washed with brine
  3. dry with materialdried over anhydrous magnesium sulfate
  4. filtrationfiltered
  5. concentrationconcentrated to an oil
  6. distillationThe oil was distilled

Sources & evidence

ORD record
ord-ab37f36e274a42dca1b463fa8575808b
Source dataset
uspto-grants-1983_08
Patent number
US04399296

Reaction notes

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