Sulfuric Acid → 2,6-Difluorobenzaldehyde

HRID 647206Notes

Reaction equation

HRID 647206 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-2cecae3ff85c4045bdb06c0b28ee2b0c
Source dataset
uspto-grants-1983_10
Patent number
US04407811

Reaction notes

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