4'-Methoxyacetophenone → 4-Hydroxyphenylglyoxal

HRID 865610Notes

Reaction equation

HRID 865610 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 4-hydroxyphenyl 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-ef556ceca24241879f3eb74e05b7cce0
Source dataset
uspto-grants-1996_10
Patent number
US05567299

Reaction notes

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