Sulfuric Acid → 2-(2',6'-Dimethylphenyl)ethylglyoxal diethyl acetal

HRID 1589173Notes

Reaction equation

HRID 1589173 reaction equation
[Mg].[CH3:2][C:3]1[CH:8]=[CH:7][CH:6]=[C:5]([CH3:9])[C:4]=1[CH2:10][CH2:11]Br.N1(N[C:20](=[O:28])[CH:21]([O:25][CH2:26][CH3:27])[O:22][CH2:23][CH3:24])CCCCC1.S(=O)(=O)(O)O>O1CCCC1>[CH2:23]([O:22][C:21]([O:25][CH2:26][CH3:27])([CH2:11][CH2:10][C:4]1[C:3]([CH3:2])=[CH:8][CH:7]=[CH:6][C:5]=1[CH3:9])[CH:20]=[O:28])[CH3:24]

Participants

6

Reactant 4

HCID 1118Sulfuric AcidHCID 5462224Magnesium2×HCID 134801962-(2-Bromoethyl)-1,3-dimethylbenzeneHCID 54475451Diethoxyacetic acid piperidinyl amide

Product 1

HCID 201904282-(2',6'-Dimethylphenyl)ethylglyoxal diethyl acetal

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

9 g of magnesium turnings are covered with 400 ml of dry tetrahydrofuran and the mixture is warmed to boiling. To that mixture is then added 2-(2',6'-dimethylphenyl)-1-bromoethane at such a rate that a gentle boiling is maintained. When the magnesium turnings have reacted the solution containing the Grignard reagent is cooled to room temperature. The reaction mixture is then added dropwise, over a period of 3 hours, to a cooled (0°-5° C.) solution of diethoxyacetic acid piperidinyl amide (80.8 g) in 200 ml of dry tetrahydrofuran. After the addition is complete, the reaction mixture is stirred for two hours at about 5° C. The mixture is then poured into a cold 2% sulfuric acid solution (1000 ml). The solution is extracted with toluene and the combined toluene extracts are washed with water and evaporated to dryness to give a residue of about 95 g. The residue is distilled under reduced pressure. The forefraction distilling below 120° C./0.6 mmHg is discarded and the rest, about 66 g, is crude 2-(2',6'-dimethylphenyl)-ethylglyoxal diethyl acetal, which is used without purification in step (b).

Workup

  1. temperaturethe mixture is warmed to boiling
  2. additionThe reaction mixture is then added dropwise, over a period of 3 hours
  3. additionAfter the addition
  4. extractionThe solution is extracted with toluene
  5. washthe combined toluene extracts are washed with water
  6. customevaporated to dryness
  7. customto give a residue of about 95 g
  8. distillationThe residue is distilled under reduced pressure
  9. distillationThe forefraction distilling below 120° C./0.6 mmHg
  10. customis used without purification in step (b)

Sources & evidence

ORD record
ord-69856e3f597a43079aee723067946d80
Source dataset
uspto-grants-1986_02
Patent number
US04568686

Reaction notes

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