Benzoic Acid → Phenylglyoxylic Acid

HRID 597277Notes

Reaction equation

HRID 597277 reaction equation
N([O-])=O.[Na+].C([C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=1)(=O)C.Cl.P([O-])([O-])([O-])=O.[Na+].[Na+].[Na+].N([O-])=O.N[C:27](N)=[O:28].[C:30]([OH:38])(=[O:37])C1C=CC=CC=1>O>[C:8]1([C:27](=[O:28])[C:30]([OH:38])=[O:37])[CH:9]=[CH:10][CH:11]=[CH:12][CH:13]=1

Participants

9

Reactant 7

HCID 243Benzoic AcidHCID 313Hydrochloric Acid3×HCID 946Nitrite2×HCID 1176UreaHCID 7410Acetophenone2×HCID 24243Trisodium PhosphateHCID 23668193Sodium Nitrite2×

Product 1

HCID 11915Phenylglyoxylic Acid

Reagents, catalysts & solvents 1

HCID 962WaterSolvent3×

Procedure

A solution of sodium nitrite (35g; 0.5 mole) in water (100 ml.) was added steadily over 95 minutes to a stirred mixture of acetophenone (24.0g; 0.2 mole) in 6N-hydrochloric acid (200 ml.) at 65°. 1.3M Trisodium phosphate (165 ml.) was then added over ca. 3 minutes to raise the pH of the mixture to 1.8. Simultaneously, addition of a second solution of sodium nitrite (28g; 0.4 mole) in water (70 ml.) was commenced, which took 75 minutes to complete. The pH of the mixture was kept below pH 3.5 during the nitrite addition by addition of hydrochloric acid as required, then was lowered to pH 2. Urea (2g) in water (10 ml.) was then added to decompose any excess of nitrite. The mixture was cooled to 20°, and extracted at pH 4.2 with chloroform (2 × 100 ml.) to give a mixture of unreacted acetophenone and benzoic acid (3.8 g; 16%). The aqueous layer was further acidified with 10N hydrochloric acid (50 ml.) and extracted with ethyl acetate (5 × 100 ml.). The combined water-washed extracts were evaporated to dryness and the residual oil (30g.) was crystallised from carbon tetrachloride (25 ml.) to give phenylglyoxylic acid as almost colourless prisms (9.2g; 31%) m.p. 63.5°-65.5°. Dilution of the mother liquors with increasing quantities of light petroleum (b.p. 40°-60°) gave further crops of phenylglyoxylic acid [8.7g (29%) m.p. 60°-64°, and 1.6g (5%)].

Workup

  1. temperatureto raise the pH of the mixture to 1.8
  2. temperatureThe mixture was cooled to 20°
  3. extractionextracted at pH 4.2 with chloroform (2 × 100 ml.)
  4. customto give
  5. extractionextracted with ethyl acetate (5 × 100 ml.)
  6. washThe combined water-washed extracts
  7. customwere evaporated to dryness
  8. customthe residual oil (30g.) was crystallised from carbon tetrachloride (25 ml.)

Sources & evidence

ORD record
ord-ac9e6d5eb82e48bfbc91f97ba5cb4621
Source dataset
uspto-grants-1977_03
Patent number
US04013680

Reaction notes

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