反应详情

13.8 g of bromine were added dropwise to a solution of 11.5 g of sodium hydroxide in 60 ml of water at 5°-10° C., and a solution of 8.1 g (0.029 mol) of trans-3,3-dimethyl-2-(2-chloro-2-(4-chloro-phenyl)-vinyl)-1-acetylcyclopropane in 30 ml of dioxane was then added dropwise at 0°-5° C. The mixture was subsequently stirred for 3 hours, without cooling, poured onto 250 ml of water and extracted twice with 50 ml of ether each time. The aqueous phase was freed from adhering ether in vacuo and then brought to pH 2 by adding aqueous hydrochloric acid. After crystallization, the product was filtered off and rinsed with water. 6.2 g (77% of theory) of trans-3,3-dimethyl-2-(2-chloro-2-(4-chloro-phenyl)-vinyl)-cyclopropanecarboxylic acid were thus obtained in the form of pale yellow-colored crystals with a melting point of 103°-106° C.

1. temperaturewithout cooling
2. extractionextracted twice with 50 ml of ether each time
3. additionby adding aqueous hydrochloric acid
4. customAfter crystallization
5. filtrationthe product was filtered off
6. washrinsed with water