Chinoin Gyogyszer Es Vegyeszeti Termekek Gyara Rt.

Rezso Kolta

Rudolf Soos

Sandor Zoltan

Eva Somfai

Laszlo Toke

Gyorgy Hidasi

Jozsef Nemes

Ferenc Faigl

Elemer Fogassy

Maria Tary

Jozsef Muskovits

Ferenc Lindwurm

Tivadar Puskas

Jozsef Bozzay

Peter Bencsik

The present invention relates to a process for the selective separation of esters of the general formula II

Process for the separation of esters

The invention relates to a process for the preparation of enantiomers of trans vinyl-cyclopropane carboxylic acids of the formula I, ##STR1## wherein R is a methyl group or chlorine atom, by resolution of racemic trans compound or mixture of racemic cis and trans compounds by using (+)- or (-)-N-(1-formamido-2,2,2-trichloroethyl)-piperazine as a resolving agent in a polar solvent then separating the crystallizing salt of (+)-trans carboxylic acid and (-)-resolving agent or (-)-trans carboxylic acid and (+)-resolving agent from the mother liquor by filtration and obtaining the enantiomers by acidifying the mother liquor or the salts suspended in water followed by extraction with a solvent and evaporation. The products so obtained may be used as starting materials for the preparation of insecticides.

Process for the preparation of optically active cyclopropane carboxylic

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

Growing community of inventors

Budapest, Hungary

Rezso Kolta