Basf Aktiengesellschaft

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Badische Anilin- & Soda-fabrik Aktiengesellschaft

Basfaktiengesellschaft

Bask Aktiengesellschaft

Joachim Paust

Hansgeorg Ernst

Walter Dobler

Hagen Jaedicke

Michael John

Udo Rheude

Wolfgang Krause

Rolf Hartmuth Fischer

Werner Hoffmann

Bernhard Schulz

Friedhelm Balkenhohl

Christoph Wegner

Wolfram Schmidt

Hans-Martin Weitz

Friedrich Vogel

Hartmut Leininger

Wolfgang Siegel

Martin Jochen Klatt

Axel Nuerrenbach

Sigberg Pfohl

Joachim U Schneider

Wolfgang Littmann

Markus Niebel

Klaus Kaiser

Hardo Siegel

Walter Himmele

Eckhard Hickmann

Horst Hartmann

Manfred Eggersdorfer

Karl Von Fraunberg

Juergen Frank

Michael Hullmann

Klaus Schmieder

Peter Eckes

Henning-Peter Gehrken

Horst Schumacher

Wolfgang Kriegl

Guenter H Knaus

Wolfgang Schul

Rainer Becker

Herbert Naarmann

Hartwig Voss

Klaus Penzien

Dieter Horn

Marco Thyes

Helmut Auweter

Hans-Heiner Wuest

Fritz-Frieder Frickel

Werner Aquila

Karin Sperling-Vietmeier

Joachim Meyer

Horst Weiss

Heinz Eckhardt

Paul Grafen

Hartwig Fuchs

Wolfram Burst

Norbert Mueller

Heinz Etzrodt

Heribert Bohn

J&ouml;rg Botzem

Jens Rieger

Klaus Henrich

Günter Wegner

Franz Feichtmayr

Klaus-Peter Pfaff

Roland Betz

Hans-Ulrich Scholz

Reinhard Kaczmarek

Walter Trautmann

Peter Munster

Helmut Guembel

Otto Worz

Arno Kochner

Armin Bertram

Gunter Dauwel

Klaus Kr&auml;mer

Henning Kroesche

Axel Nurrenbach

Ulrich Schaefer-Luederssen

Walter Dobuler

Alfred Mitschker

Helmut Indest

Ulrich Von Deessen

The present invention relates to a process for the preparation of R- and S-lipoic acid and R- and S-dihydrolipoic acid comprising (a) reaction of 

Process for the preparation of lipoic acid and dihydrolipoic acid

Processes for the preparation of R-lipoic acid or S-lipoic acid comprising a process step selected from

Method for producing lipoic acid and dihydrolipoic acid

Preparation of N-acylamino acid esters and N-acylamino acetals

A process for the preparation of 1,1,4,4-tetramethoxy-2-butene by reacting 2,5-dimethoxydihydrofuran with methanol in the presence of acids comprises carrying out the reaction in the presence of solid catalysts having acidic centers.

Preparation of 1,1,4,4-tetramethoxy-2-butene

Phosphonium salts are prepared by reacting an alkanol with triarylphosphine and sulfonic acids in a solvent.

Preparation of phosphonium salts

In the 2 &THgr; diffractogram of an enantiomerically pure crystalline (R)- or (S)-lipoic acid, the most intense reflection line in the range from 13&deg; to 30&deg; is that at 2 &THgr;&equals;23&deg;.

Crystal modification of lipoic acid

Process for preparing folic acid

Organosulfur compounds can be used in complexes with carotenoids for effecting a bathochromic shift in the absorption bands of carotenoids in the UV/vis spectrum. Carotenoid formulations comprising these complexes, a process for preparing these formulations and their use in the food, cosmetics and pharmaceutical sectors are described.

Use of organosulfur compounds for effecting a bathocromic shift in the UV/vis absorption bands of carotenoids

Phosphonium salts are prepared by reacting an alkanol with triarylphosphine and alkyl or trifluoromethane sulfonic acids in a solvent.

A process for preparing 4-hydroxy-1,2,2-trimethylcyclopentyl methyl ketones of the general formula I, in particular of the (1R,4S)-4-hydroxy-1,2,2-trimethylcyclopentyl methyl ketone of the formula Ia ##STR1## which is required for preparing the red dye capsorubin which is in demand, starts from 2,2,6-trimethylcyclohexanones of the general formula II ##STR2## where R is hydrogen or a protective group, via the novel intermediates of the general formulae V and VI ##STR3## by diastereoselective epoxidation and reaction of the resulting 7-oxabicyclo[4.1.0]heptanes of the general formula VIII ##STR4## with Lewis acids and, where appropriate, removal of the protective group. Also claimed are the novel intermediates of the formula V and their (1S) and (1R) isomers and those of the formula VIII as well as their (1R,3S,6S), (1S,3S,6R) and (1R,3R,6S) isomers.

Preparation of (1R,4S)-4-hydroxy-1,2,2-trimethylcyclopentyl methyl

Preparing (3R, 3'R)-zeaxanthin of the formula I ##STR1## starting from (4-hydroxy-2,2,6-trimethylcyclohexanone of the formula II ##STR2## via the novel intermediates (4R,6R)-1-formyl-2,2,6-trimethyl-7-oxabicyclo[2.2.1]heptane of the formula IV ##STR3## (4R,6R)-1-(3-oxo-1-butenyl)-2,2,6-trimethyl-7-oxabicyclo[2.2.1]heptane of the formula V ##STR4## (4R,6R)-1-(3- hydroxy-3-methyl-1,4-pentadienyl)-2,2,6-trimethyl-7-oxabicyclo[2.2.1]heptan e of the formula VI ##STR5## [5-(4R,6R)-(4-hydr oxy-2,2,6-trimethyl-1-cyclohexylidene)-3-methyl-1,3-pentadienyl]triarylphos phonium salt of the formula iso-III ##STR6## where Ar is aryl and X is one equivalent of an anion of a strong acid. The (4R,6R)-1-formyl-2,2,6-trimethyl-7-oxabicyclo[2.2.1]heptane of formula IV is obtained by reacting the ketone of the formula II with dichloromethyllithium, which can be prepared by metallation of dichloromethane with butyllithium or lithium diisopropylamide.

Preparation of zeaxanthin, intermediates for this preparation, and the

A process for the preparation of pure trans- and cis-4-hydroxy-2, 2,6-trimethylcyclohexan-1-one from a mixture of these isomers comprises fractionally rectifying the isomeric mixture in a suitable column having from about 30 to 80 theoretical separation stages at temperatures of preferably from 50.degree. to 130.degree. C. and a pressure in the range from 0.1 to 5 mbar. The products are essential intermediates for the preparation of 3-hydroxycarotenoids such as cryptoxanthin and zeaxanthin.

Preparation of pure trans- and

A process for preparing polyenecarbonyl compounds having a high all-E content and their acetals or ketals by aldol condensation or Horner-Emmons reaction comprises carrying out the reaction, for the purposes of the preferred formation of a double bond of E configuration and in order to maintain the E configuration of the double bonds in the stating compounds as completely as possible, in the presence of oxygen or an oxygen-inert gas mixture or nitric oxide or a nitric oxide-inert gas mixture and/or in the presence of specific stable radicals and/or in the presence of quinones or quinone derivatives.

Preparation of polyenecarbonyl compounds having a high content of the

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Neuhofen, Germany

Joachim Paust