Chinoin Gyogyszer Es Vegyeszeti Termekek Gyara Rt.

Richter Gedeon Nyrt.

Alkaloida Vegyeszeti Gyar

Zentiva K.s.

Ferenc Faigl

Rudolf Soos

Elemer Fogassy

Laszlo Toke

Jindrich Richter

Jozsef Rakoczi

József Bódi

Jozsef Nemes

Rezso Kolta

Jozsef Bozzay

Ferencné Kassai

Elemer Foggassy

Béla Mátravölgyi

Elemér Fogassy

Ágnes Mizsák

Dorottya Kiss-Bartos

Peter Bencsik

Maria Acs

Robert Klvana

Katalin Szöke

Krisztina Temesvári

Viktor UJVÁRI

Jan Doubsky

Zoltán NÉMET

Róbert Kiss

János FaragÓ

The subject-matter of the invention is process for the separation of optical isomers of racemic 3-alk-3-carboxylic acid ethyl esters of formula rac-I with the resolving agent (II) (&#x2212;)-2,3:4,5-di-O-izopropylidene-2-keto-L-gulonic acid (hereinafter: diacetone-L-ketogulonic acid).

Process for the separation of optical isomers of racemic 3-alkylpiperidine-carboxylic acid ethyl esters

Diastereomer salts of phenylalanine and N-acyl derivatives thereof and

The invention relates to a new process for separating the four stereoisomers of the cyclopropanecarboxylic acids of the formula ##STR1## wherein R stands for a methyl group or a halogen atom. The process comprises

Process for the separation of isomeric cyclopropane-carboxylic acids

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

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Budapest, Hungary

Ferenc Faigl