Ethanol → 5-Ethyl-5-methyl-4-oxohept-2-enoic acid

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Reaction Steps

The product of the preparation immediately above was dissolved in 400 ml. of ethanol and brought to a boil. To it was quickly added 40 g. of potassium hydroxide in 360 ml. of water, and the temperature was held at 72° for 2 minutes. The mixture was then poured immediately into 1 liter of ice-water, and 50 g. of sodium chloride was added. The aqueous mixture was extracted with 1000 ml. of diethyl ether, and the aqueous layer was made acid to pH 1 with concentrated hydrochloric acid. It was then extracted 4 times with 500 ml. portions of dichloromethane, and the organic layers were combined, dried over magnesium sulfate and evaporated under vacuum to obtain 20 g. of the desired acid, as a mixture with 5-ethyl-2-hydroxy-5-methyl-4-oxoheptanoic acid, the presence of which was indicated by nuclear magnetic resonance signals, δ4.35 (q, 1H); 2.6-3.8 (m, 2H).

Provenance & Evidence