Asta Medica, Aktiengesellschaft

Arzneimittelwerk Dresden Gmbh

Viatris Gmbh & Co Kg

Rainer Gewald

Thomas Beisswenger

Gunter Laban

Klaus Huthmacher

Herbert Klenk

Horst Bethge

Stephan Rautenberg

Frank Hubner

Alfred Olbrich

Roland Moller

Gerhard Sator

Matthias Olbrich

The invention relates to a process for the production of (R)- or (S)-8-chloro-6-hydroxyoctanoic acid alkyl esters of the general formula (R)-II or (S)-II, in which R means Calkyl, from 8-chloro-6-oxo-octanoic acid alkyl esters of the general formula I, in which R has the above meaning. The desired enantiomers are produced biocatalytically in an enantioselective reduction, wherein as desired the strains Mucor racemosus are used for (S)-II compounds and Geotrichum candidum for (R)-II compounds. The resultant esters may, in known manner, be converted stereospecifically into (R)-&#x3b1;-lipoic acid.

Process for the enantioselective reduction of 8-chloro-6-oxo-octanoic acid alkyl esters

The invention relates to a process for the preparation of compounds of the general formula Iin which Rrepresents a C-C-alkyl group, a C-C-cycloalkyl group, a C-C-aralkyl group or a mono- or bi-nuclear aryl group, in which a ketone of formula IIwherein Ris as defined above, is subjected to asymmetric hydrogenation.

Method for producing enantiomer-free 6,8 dihydroxy octanoic acid esters by means of asymmetric, catalytic hydrogenation

The invention relates to a process for the preparation of compounds of the general formula I

Process for the preparation of enantiomerically pure 3-hydroxyoctanedioic acid diesters by asymmetric catalytic hydrogenation

The invention relates to a process for the preparation of compounds of the general formula I ##STR1## in which R.sup.1 and R.sup.2 are identical or different and are a C.sub.1 -C.sub.20 -alkyl group, C.sub.3 -C.sub.12 -cycloalkyl group, C.sub.7 -C.sub.12 -aralkyl group or a mono- or binuclear aryl group, in which a ketone of the formula III or IV ##STR2## in which R.sup.1 and R.sup.2 have the above meaning, is asymmetrically hydrogenated.

Process for the preparation of enantiomerically pure

The invention relates to the production and purification of salts of 6,8-bis (amidiniumthio)octanoic acid, its enantiomers (+)-6,8-bis(amidiniumthio)octanoic acid and (-)-6,8-bis (amidiniumthio)octanoic acid and of the esters of these compounds as well as to their use to produce dihydrolipoic acid and .alpha.-lipoic acid.

Production and use of salts of 6,8-bis (amidiniumthio)-octanoic acid

The invention relates to (+) and (-)-8-halogen-6-hydroxy-octanoic acid enantiomers wherein the halogen is Cl, Br, or I, and their respective preparatory processes.

(+)- and (-) -8-halogen-6- hydroxy-octanoic acid its salts and esters

(+)- or (-) -8-halogen-6-hydroxy-octanoic acid, its salts and esters,

The invention relates to the production and purification of salts of 6,8-bis(amidiniumthio) octanoic acid, its enantiomers (+)-6,8-bis(amidiniumthio)octanoic acid and (-)-6,8-bis (amidiniumthio)octanoic acid and of the esters of these compounds as well as to their use to produce dihydrolipoic acid and .alpha.-lipoic acid.

Production and use of salts of 6, 8-bis (amidiniumthio) -octanoic acid

The synthesis of pure enantiomers of 8-chloro-6-sulfonyloxy-octanoic acids and their alkyl esters and of pure enantiomers of 6,8-dichloro-octanoic acid and its alkyl esters as intermediates for the synthesis of the enantiomers of .alpha.-liponic acid as well as a method for converting the two enantiomers of 8-chloro-6-hydroxy-octanoic acid into an enantiomer of .alpha.-liponic acid.

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Dresden, Germany

Rainer Gewald