| 摘要 |
A process for the preparation of a 3-(2,2-dichlorovinyl)-2,2-dimethyl-cyclopropane-1-carboxylic acid or derivative of the formula <IMAGE> in which R is hydrogen, alkali metal, ammonium, an equivalent of an alkaline earth metal, alkyl, or a radical customary in the alcohol part of pyrethroids, comprising reacting a 3-formyl-2,2-dimethyl-cyclopropane-1-carboxylic acid derivative of the formula <IMAGE> with a dichloromethane derivative of the formula <IMAGE> in which R1 and R2 each independently is alkyl, phenyl, alkoxy or phenoxy, or together are alkanediyl or alkanedioxy, in the presence of a base at a temperature between about -50 DEG and +50 DEG C. The products are intermediates for the preparation of esters of pyrethroid-like insecticidal activity.
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