| 摘要 |
PURPOSE:To obtain the objective trans-isomers under extremely mild conditions as compared with those in a well-known method by using tertiary alkylamines in converting the cis-isomers of the subject compounds into the trans-isomers. CONSTITUTION:Reaction of cis/trans mixed 2,2-dimethyl-3-(2,2-dihalovinyl) cyclopropanecarbixylic acids expressed by the formula (X and Y are halogen) with tertiary alkylamines in a molar amount of normally (1/100)-5 times, preferably (1/4)-1 based on the aforementioned compounds in the coexistence of an iodine compound in a molar amount of normally 1-(1/100), preferably (1/50)-(1/4) based on the above-mentioned raw materials normally at 10-150 deg.C, preferably 60-120 deg.C temperature is carried out to afford the trans-isomers with lower toxicity to warm-blooded animals than that of the cis-isomers which are compounds, expressed by the formula and useful as an intermediate for insecticides, such as permethrin or cypermethrin, under mild conditions. |
