Benzil → 1,2-Bis(4-methylphenyl)-1,2-ethanedione

HRID 2220680Notes

Reaction equation

HRID 2220680 reaction equation
C1(C(C(C2C=CC=CC=2)=O)=O)C=CC=CC=1.[CH3:17][C:18]1[CH:23]=[CH:22][C:21]([C:24]([CH:26]([C:28]2[CH:33]=[CH:32][C:31]([CH3:34])=[CH:30][CH:29]=2)[OH:27])=[O:25])=[CH:20][CH:19]=1>O.N1C=CC=CC=1>[CH3:17][C:18]1[CH:19]=[CH:20][C:21]([C:24]([C:26]([C:28]2[CH:29]=[CH:30][C:31]([CH3:34])=[CH:32][CH:33]=2)=[O:27])=[O:25])=[CH:22][CH:23]=1

Participants

5

Reactant 2

HCID 8651BenzilHCID 2248484,4'-DIMETHYLBENZOIN

Product 1

HCID 769961,2-Bis(4-methylphenyl)-1,2-ethanedione

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 1049PyridineSolvent

Procedure

4,4′-Dimethylbenzil was prepared on the basis of a known method for benzil (L. F. Tietze, Th. Eicher, Reaktionen und Synthesen[Reactions and Syntheses], R. Stierlein, Chem. Ber. 22/1 (1889) 37). 420 g of CuSO4·5H2O (1.68 mol) were dissolved in a mixture of 350 ml of water and 400 ml of pyridine bases while heating. 190 g (0.79 mol) of crude 4,4′-dimethylbenzoin were added to the still warm solution, and refluxing was effected for 4 hours. After cooling to room temperature, the crude product was filtered off and washed with water. The filter residue was taken up in ether, filtered and dried with Na2SO4. After the solution had been evaporated down to about 500 ml, 4,4′-dimethylbenzil crystallized out in the form of pale yellow crystals. Depending on their use, they were recrystallized from ethanol (yield 119.9 g (64%, based on crude 4,4′-dimethylbenzoin used); m.p.: 104° C., literature: 104-105° C. The IR spectrum of 4,4′-dimethylbenzil is shown in FIG. 9.

Workup

  1. temperaturewhile heating
  2. temperaturerefluxing
  3. filtrationthe crude product was filtered off
  4. washwashed with water
  5. filtrationfiltered
  6. dry with materialdried with Na2SO4
  7. customAfter the solution had been evaporated down to about 500 ml, 4,4′-dimethylbenzil
  8. customcrystallized out in the form of pale yellow crystals
  9. customwere recrystallized from ethanol (yield 119.9 g (64%, based on crude 4,4′-dimethylbenzoin used)
  10. custom104-105° C

Sources & evidence

ORD record
ord-78e5a1094e794003a2beb0a635abe0bb
Source dataset
uspto-grants-2008_08
Patent number
US07417247B2

Reaction notes

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