Evonik Degussa Gmbh

Degussa Aktiengesellschaft

Aventis Research & Technologies Gmbh & Co Kg

Degussa Gmbh

Martin Hateley

Christoph Weckbecker

Klaus Huthmacher

Christoph Kobler

Jürgen Bilz

Thomas Häussner

Dieter Buss

Philipp Roth

Barbara Jaeger

Matthias Beller

Ralf Jackstell

Thomas Riermeier

Thomas Lehmann

Rainer Peter

Rainer Sanzenbacher

Daniel Schichl

Barbara Jäger

Thomas Hauhlner

Irina Jovel

Christian Reufer

A method for preparing &#x3b1;-keto acids, especially &#x3b1;-ketomethionine, and/or derivatives thereof, whereby an aldehyde is reacted with thiols to give a corresponding dithioacetal, the dithioacetal formed, is reacted with an electrophile in the presence of a strong base, and the resulting &#x3b1;,&#x3b1;-(dithio)carboxylic acid is solvolyzed with acid-catalysis to release thiol and give the &#x3b1;-keto acid or a derivative thereof. Umpolung of aliphatic or aromatic aldehydes is effected by reaction with thiols.

Process for preparing &#x3b1;-keto acids and derivatives thereof

The invention relates to a method for production of D- and/or L-methionine via D- and/or L-homoserine with subsequent chemical transformation to give methionine.

Method for production of methionine from homoserine

Ketomethionine ketals and hemiketals and derivatives thereof are useful as feed additives, in particular for the nutrition of ruminants.

Ketomethionine ketals and derivatives thereof

The present invention relates to a sequence for the preparation of amino acids, for example alpha amino acids, in particular methionine, by making use of an amidocarbonylation reaction and reuse of the catalyst.

Process for preparing amino acids using amidocarbonylation reaction

The present invention relates to the preparation of &#x3b1;-hydroxy ketones of the general formula I. In particular, the invention relates to novel imidazolinium carboxylate adducts and to a novel process for using catalytic amounts of imidazolium and imidazolinium carboxylate adducts in the acyloin reaction of aldehydes to prepare hydroxy ketones of the general formula I, where R and R' are the same or different and are each H or a straight-chain or branched and optionally substituted C-C-alkyl radical, and R&#x2033;&#x2550;HCSCHCH, t-butyl, n-butyl, sec-butyl, n-propyl, i-propyl, an optionally heteroatom-substituted C-C-aryl, heteroaryl, C-C-arylalkyl, especially phenylmethyl, where phenyl may again be heteroatom-substituted, or heteroalkyl.

Preparation of &#x3b1;-hydroxy ketones via carbene-catalyzed umpolung reaction of aldehydes

The present invention relates to a sequence for the preparation of amino acids, for example alpha-amino acids, in particular methionine, by making use of an amidocarbonylation reaction in the presence of a cobalt carbonyl catalyst and separating the catalyst in the form of a Co(N-amino acid)compound.

Process for preparing amino acids using the amidocarbonylation reaction

A process for the preparation of &#x3b1;-substituted carboxylic acids from the series including &#x3b1;-hydroxycarboxylic acids and N-substituted-&#x3b1;-aminocarboxylic acids by cathodic carboxylation with carbon dioxide of a compound corresponding to the general formula R&#x2014;C(&#x2550;X)Rwhich is constituted by aldehydes, ketones or N-substituted imines. In the past, that carboxylation has taken place in an undivided electrolytic cell with the use of a sacrificial anode. As described herein, the carboxylation takes place in the absence of a sacrificial anode in an electrolytic cell divided by a separator, at a diamond film cathode. The anode is formed of a material which is stable under electrolytic conditions; in particular, it is a diamond film electrode. The catholyte includes an organic solvent and a conducting salt.

Process for the preparation of &#x3b1;-substituted carboxylic acids from the series comprising &#x3b1;-hydroxycarboxylic acids and n-substituted-&#x3b1;-aminocarboxylic acids

Process for racemization of n-acylamino acids by means of transition metal catalysts

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Aschaffenburg, Germany

Martin Hateley