Water → chrysanthemic acid d-trans-form

Participants

Reaction Conditions

Reaction Steps

In a 100 ml flask, 2.0 g of an ethyl chrysanthemate having the optical isomer ratio of 3.6% of (-)-cis, 19.1% of (+)-cis, 10.5% of (-)-trans and 66.9% of (+)-trans forms by weight, was dissolved into 18.0 g of n-heptane under nitrogen. To the solution was added 0.7 g of aluminum chloride, and the mixture was stirred at a temperature of 70° C. for 3 hours. Thereafter, water was added to the reaction mixture to decompose the aluminum chloride. The organic layer separated was evaporated to remove the solvent, and the residue was mixed with 6.1 g of an aqueous 10% sodium hydroxide solution and stirred at a temperature of 100° C. for 2.5 hours to effect the hydrolysis. The reaction mixture was extracted with toluene to separate the neutral substance. The aqueous layer was acidified with a diluted sulfuric acid and then extracted with toluene. The toluene layer was washed with water, dried and evaporated to remove the solvent. Distillation in vacuo yielded 1.32 g of a trans-chrysanthemic acid boiling at 110° to 116° C./2 mmHg. Its analysis by gas-chromatography showed the optical isomer ratio of 0.9% of (-)-cis, 6.3% of (+)-cis, 12.4% of (-)-trans and 80.4% of (+)-trans forms by weight.

Provenance & Evidence