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

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Reaction Conditions

Reaction Steps

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).

Provenance & Evidence