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

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Reaction Steps

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).

Provenance & Evidence