Ethyl Acetoacetate → Ethyl 2-acetyl-5-chlorohex-4-enoate

Beteiligte Stoffe

Reaktionsschritte

To a solution of 46 g sodium (2 g atom) in 500 ml ethanol at reflux, in a 2-liter flask equipped with mechanical stirrer, and addition funnel, was added 325 g ethyl acetoacetate (2.5 mole) over 30 minutes. The resulting solution of enolate was refluxed for 15 minutes, and then 250 g (2.0 mole) 1,3-dichlorobut-2-ene was added dropwise at such a rate as to maintain reflux with gentle heating towards the end of the addition. After addition, refluxing and stirring were maintained for 4 hours, the condenser converted for distillation, and ethanol removed as 500 ml distillate. The residual product was cooled, water and 1.2 N hydrochloric acid were added and the organic layer separated. The aqueous portion was extracted with ether, the organic layers combined, washed with water and brine, filtered through sodium sulfate and evaporated in vacuo to give 485 g dark yellow oil (96%, based on dichlorobutene). Vpc showed 73% of trans plus cis product, together with other volatiles.

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