4'-Methoxyacetophenone → 4-Hydroxyphenylglyoxal

HRID 1440641Notes

Reaction equation

HRID 1440641 reaction equation
[CH3:1][C:2]([C:4]1[CH:9]=[CH:8][C:7]([O:10]C)=[CH:6][CH:5]=1)=[O:3].C1(C)C(S([O-])(=O)=[O:19])=CC=CC=1.C([N+](CC)(CC)CC)C>[Pt].CO>[OH:10][C:7]1[CH:6]=[CH:5][C:4]([C:2]([CH:1]=[O:19])=[O:3])=[CH:9][CH:8]=1

Participants

5

Reactant 2

HCID 74764'-MethoxyacetophenoneHCID 23176919HCID 23176919, compound

Product 1

HCID 905684-Hydroxyphenylglyoxal

Reagents, catalysts & solvents 2

HCID 23939PlatinumCatalystHCID 887MethanolSolvent

Procedure

In a standard undivided cell having a platinum anode and a glossy carbon cathode (33 cm2 each) there is charged 200 g methanol (65° C.), 11.3 g of 4-methoxyacetophenone (4-MAP), and 11.5 g tetraethylammonium toluene sulfonate. This electrolysis is conducted at a current density of about 30 mA/cm2 until a current passage of 50.9 Ah is charged (633% of theoretical value). According to an iodometrical determination, a current efficiency of 50% is obtained. About 150 g methanol is distilled off and the remaining solution is neutralized with aqueous NaHCO3 and extracted with ethyl acetate. The extract is dried and the solvent is removed by evaporation. The remaining oil is separated by column chromatography (silica gel, MTBE/cyclohexane =1/4). The acetal product is 6.4 g of 2,2-dimethoxy-1-[4-methoxyphenyl]-ethanale (41% based on 4-MAP). Subsequent hydrolysis at 62° C. yields 4hydroxyphenyl glyoxal (HPGO).

Workup

  1. additionis charged (633% of theoretical value)
  2. customa current efficiency of 50% is obtained
  3. distillationAbout 150 g methanol is distilled off
  4. extractionextracted with ethyl acetate
  5. customThe extract is dried
  6. customthe solvent is removed by evaporation
  7. customThe remaining oil is separated by column chromatography (silica gel, MTBE/cyclohexane =1/4)
  8. customSubsequent hydrolysis at 62° C.

Sources & evidence

ORD record
ord-09a21cbf1cf54092908aef72a776e0fc
Source dataset
uspto-grants-1996_03
Patent number
US05500099

Reaction notes

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