Sodium Hydroxide → 3-(2,2-Dibromovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

36.2 g. of 2,2-dimethyl-3-(2,2-dibromovinyl)-cyclopropane-1-carboxylic acid ethylester (purity: 90%, cis) trans ratio: 45:65/, 4 g. of a 25% aqueous sodium hydroxide solution and 0.2 g. of tricaprylmethyl ammonium chloride are stirred at 100° C. for 30 minutes, whereupon three 4-g. portions of the sodium hydroxide solution are added in 30 minutes intervals and stirring is continued for altogether 240 minutes. The mixture is cooled to 20° C., diluted with 100 ml. of water and extracted with 10 ml. of benzene. The aqueous solution is admixed with 12 g. of a 36% aqueous hydrochloric acid solution at 70° C. and cooled to room temperature with stirring. The precipitated acid is dissolved in 60 ml. of benzene, the solution is separated and the solvent is evaporated. 30.0 g (92%) of 2,2-dimethyl-3-(2,2-dibromovinyl)-cyclopropanecarboxylic acid are obtained. Cis/trans ratio: 40:60.

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