Chinoin Gyogyszer Es Vegyeszeti Termekek Gyara Rt.

Ferenc Lindwurm

Eva Somfai

Rudolf Soos

Sandor Zoltan

Gyorgy Hidasi

Rezso Kolta

Jozsef Muskovits

Tivadar Puskas

The invention relates to a new process for the preparation of cyclopropanecarboxylic acids of the formula (I) ##STR1## wherein X and Y independently stand for halogen, by the alkaline hydrolysis of the corresponding alkyl esters having 1 to 6 carbon atoms in the alkyl moiety, in or without a water-miscible organic solvent, in the presence of a phase transfer catalyst. The hydrolysis is carried out with a 2 to 50% by weight aqueous alkali hydroxide solution. If desired, under suitable conditions the cis/trans ratio of the original ester can be altered in the end products. The cyclopropanecarboxylic acids of the formula (I) are obtained in a high purity and are useful intermediates of insecticidally active pyrethroids.

Process for the preparation of dihalovinylcyclopropanecarboxylic acids

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Budapest, Hungary

Ferenc Lindwurm