Evonik Degussa Gmbh

Barbara Jaeger

Klaus Huthmacher

Christoph Weckbecker

Christoph Kobler

Martin Hateley

Philipp Roth

Rainer Peter

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

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

Ketomethionine ketals and derivatives thereof

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Mainhausen, Germany

Barbara Jaeger