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

HRID 649344Notes

Reaction equation

C[O-].[Na+].CO[C:6](=[O:11])[C:7]([O:9][CH3:10])=[O:8].[CH3:12][C:13]([C:15]([CH3:18])([CH3:17])[CH3:16])=[O:14]>>[CH3:10][O:9][C:7](=[O:8])[C:6]([CH2:12][C:13](=[O:14])[C:15]([CH3:18])([CH3:17])[CH3:16])=[O:11]

Participants

Reactant 3

HCID 6416Pinacolone

HCID 11120Dimethyl oxalate

HCID 10942334Sodium Methoxide

Product 1

HCID 4016750methyl 5,5-dimethyl-2,4-dioxohexanoateYield 88.5%

Conditions

Temperature: 50 °C

Procedure

57.2 g (1.06 mols) of sodium methylate are suspended in 400 g of dehydrated pinacolin. 118 g of molten oxalic acid dimethyl ester are added dropwise to the suspension in the course of 1 hour. The temperature is kept at 10° C. during this addition. The mixture is subsequently stirred for 15 minutes and 84 g of a methanol/pinacolin mixture are then distilled off at 64° C. The bottom product is cooled to 50° C. and 252 g of aqueous sulphuric acid (20.9% strength by weight) are added. Separation of the phases and subsequent distillation of the organic phase gives 164.6 g of pivaloylpyruvic acid methyl ester (87.8% of the theoretical yield), purity: 99.3%.

Workup

additionThe temperature is kept at 10° C. during this addition
distillation84 g of a methanol/pinacolin mixture are then distilled off at 64° C
addition252 g of aqueous sulphuric acid (20.9% strength by weight) are added
customSeparation of the phases and subsequent distillation of the organic phase

Sources & evidence

ORD record: ord-e9984211be3348bba373b669033fe768
Source dataset: uspto-grants-1988_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04739104

Reaction notes

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