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

HRID 649339

Reaktionsgleichung

Reaktionsgleichung von HRID 649339
C(O[C:4](=[O:10])[C:5]([O:7][CH2:8][CH3:9])=[O:6])C.CC[O-].[Na+].[CH3:15][C:16]([C:18]([CH3:21])([CH3:20])[CH3:19])=[O:17]>C(O)C>[CH2:8]([O:7][C:5](=[O:6])[C:4]([CH2:15][C:16](=[O:17])[C:18]([CH3:21])([CH3:20])[CH3:19])=[O:10])[CH3:9]

Komponenten

5

Edukt 3

HCID 6416PinacoloneHCID 7268Diethyl OxalateHCID 2723922Sodium ethoxide

Produkt 1

HCID 83403Ethyl 5,5-dimethyl-2,4-dioxohexanoate

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 702EthanolLösungsmittel

Reaktionsbedingungen

Temperatur
80 °C

Versuchsvorschrift

146 g (1 mol) of oxalic acid diethyl ester are added dropwise to 367.2 g of a 20% strength sodium ethylate solution in ethanol at 5° C. in the course of one hour, whilst stirring. 100 g of technical grade pinacolin are allowed to run in and the mixture is stirred for a further 15 minutes. It is then heated to 80° C. and heated under reflux for 3 hours. The solution is subsequently evaporated to dryness in a rotary evaporator. The residue is suspended in 200 ml of toluene and the suspension is stirred with 253 g of aqueous sulphuric acid (20.9% strength by weight) at 50° C. for 1 hour. The organic phase is separated off and distilled. 177 g of pivaloylpyruvic acid ethyl ester (88.2% of the theoretical yield) are obtained with a purity of 99.6% (by analysis by gas chromatography).

Aufarbeitung

  1. stirringis stirred for a further 15 minutes
  2. temperatureheated
  3. temperatureunder reflux for 3 hours
  4. customThe solution is subsequently evaporated to dryness in a rotary evaporator
  5. stirringthe suspension is stirred with 253 g of aqueous sulphuric acid (20.9% strength by weight) at 50° C. for 1 hour
  6. customThe organic phase is separated off
  7. distillationdistilled

Quellen und Nachweise

ORD-Eintrag
ord-25d1200d10354b069f0e48c5719d097a
Quelldatensatz
uspto-grants-1988_04
Patentnummer
US04739104

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