Pinacolone → methyl 5,5-dimethyl-2,4-dioxohexanoate
Reaction equation
CO[C:3](=[O:8])[C:4]([O:6][CH3:7])=[O:5].C[O-].[Na+].[CH3:12][C:13]([C:15]([CH3:18])([CH3:17])[CH3:16])=[O:14]>C1(C)C=CC=CC=1>[CH3:7][O:6][C:4](=[O:5])[C:3]([CH2:12][C:13](=[O:14])[C:15]([CH3:18])([CH3:17])[CH3:16])=[O:8]Participants
Reactant 3
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- 5 °C
Procedure
118 g of oxalic acid dimethyl ester, warmed to 60° C., are added dropwise to a suspension of 59.4 g (1.1 mols) of sodium methylate in 200 g of toluene, cooled to 5° C., in the course of 1 hour, whilst stirring. 100 g (1 mol) of technical grade pinacolin are allowed to run rapidly into the mixture. The mixture is subsequently stirred for 15 minutes and 90 g of a methanol/toluene mixture are then distilled off, at boiling point760 : 67° to 100° C., over a packed column in the course of 3 hours. The bottom product is cooled to 40° C. and 258 g of 20.9% strength by weight aqeuous sulphuric acid are added. Phase separation is effected after thorough stirring for 1 hour. Distillation of the organic phase at boiling point0.4 : 75° C. gives 163.5 g of pivaloylpyruvic acid methyl ester (87.0% of the theoretical yield) with a purity of 99.0% (by analysis by gas chromatography).
Workup
- stirringThe mixture is subsequently stirred for 15 minutes
- distillation90 g of a methanol/toluene mixture are then distilled off
- custom67° to 100° C.
- customin the course of 3 hours
- temperatureThe bottom product is cooled to 40° C.
- addition258 g of 20.9% strength by weight aqeuous sulphuric acid are added
- customPhase separation
- stirringafter thorough stirring for 1 hour
- distillationDistillation of the organic phase
Sources & evidence
- ORD record
- ord-1aabf0dabf3042d6ba2808c77297e368
- Source dataset
- uspto-grants-1988_04
- Patent number
- US04739104
Reaction notes
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