Phenylhydrazine → Ethyl chrysanthemate

Participants

Reaction Conditions

Reaction Steps

19.64 mg (0.05 mmol) of copper complex prepared from 9.98 mg (0.05 mmol) of copper acetate monohydrate, and 18.23 mg of (R)-N-salicylidene-2-amino-1,1-diphenylpropanol, and 6.0 g(55 mmol) of 2,5dimethyl-2,4-hexadiene were charged in a 50 ml Schienk's tube wherein the atmosphere was replaced with nitrogen, and then 5.4 mg of phenylhydrazine. 1.14 g (10 mmol) of ethyl diazoacetate was added dropwise at 50° C. over 2 hours and further stirred for 1 hour at 25° C. The amount of chrysanthemic acidethyl ester formed was determined by gas chromatography. As a result, it was 1.52 g and the yield was 77.7% based on t-butyl diazoacetate and, furthermore, the trans/cis ratio was 61/39. After 2,5-dimethyl-2,4-hexadiene (boiling point: 51° C./30 mmHg) was distilled off from the reaction mixture. Then, 10 ml of an aqueous 1N sodium hydroxide solution and 5 ml of ethanol were added to 1 g of the concentrate and alkali hydrolysis was performed by stirring at 100° C. for 1 hour. The obtained chrysanthemic acid was reacted with I-menthol, and the resulted diastereomer was analyzed by gas chromatography, which showed the optical purity of (+)-trans isomer was 69% e.e. and that of (+)-cis isomer was 68% e.e.

Provenance & Evidence