Pinacolone → methyl 5,5-dimethyl-2,4-dioxohexanoate

HRID 649340Notes

Reaction equation

HRID 649340 reaction equation
[Na].CO[C:4](=[O:9])[C:5]([O:7][CH3:8])=[O:6].[CH3:10][C:11]([C:13]([CH3:16])([CH3:15])[CH3:14])=[O:12]>CCCCCC>[CH3:8][O:7][C:5](=[O:6])[C:4]([CH2:10][C:11](=[O:12])[C:13]([CH3:16])([CH3:15])[CH3:14])=[O:9]

Participants

5

Reactant 3

HCID 6416PinacoloneHCID 11120Dimethyl oxalateHCID 5360545Sodium

Product 1

HCID 4016750methyl 5,5-dimethyl-2,4-dioxohexanoateYield 85.5%

Reagents, catalysts & solvents 1

HCID 8058HexaneSolvent

Procedure

54 g (1 mol) of sodium are suspended in 300 g of n-hexane. 118 g (1 mol) of oxalic acid dimethyl ester, warmed to 60° C., are added dropwise at 0°-5° C. in the course of 1 hour. 100 g of pinacolin are then added rapidly at the same temperature. The mixture is stirred at room temperature for 15 minutes and 222 g of a n-hexane/methanol mixture are then distilled off, at boiling point760 : 50° C., over a 50 cm high packed column in the course of 6 hours. 234.5 g of aqueous sulphuric acid (20.9% strength by weight) are stirred into the bottom product. Separation of the phases and subsequent distillation of the organic phase give, at boiling point8 : 105° C., 159 g of pivaloylpyruvic acid methyl ester (85.0% of the theoretical yield) with a purity of 99.4% (by analysis by gas chromatography).

Workup

  1. additionare added dropwise at 0°-5° C. in the course of 1 hour
  2. distillation222 g of a n-hexane/methanol mixture are then distilled off
  3. custom50° C.
  4. customin the course of 6 hours
  5. stirring234.5 g of aqueous sulphuric acid (20.9% strength by weight) are stirred into the bottom product
  6. customSeparation of the phases and subsequent distillation of the organic phase
  7. customgive

Sources & evidence

ORD record
ord-261886c43b3c4167bc3d18d0a1941a94
Source dataset
uspto-grants-1988_04
Patent number
US04739104

Reaction notes

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