Dsm Fine Chemicals Austria Nfg Gmbh & Co. Kg

Peter P&ouml;chlauer

Herbert Mayrhofer

Irma Wirth

Herfried Griengl

Rudolf Neuhofer

Peter Riebel

Dean Vincent Johnson

Process for the preparation of optically highly pure (R)- and (S)-&agr;-hydroxycarboxylic acids, in which either isolated, impure (R)- and (S)-&agr;-hydroxycarboxylic acids prepared by acidic hydrolysis of the (R)- and (S)- cyanohydrins obtained by enzyme-catalyzed addition of a cyanide group donor to the corresponding aldehydes or ketones are recrystallized in an aromatic hydrocarbon, optionally in the presence of a cosolvent, and optically highly pure (R)- and (S)-&agr;-hydroxycarboxylic acids having an optical purity of over 98%ee are obtained or the hydrolysis solution obtained by acidic hydrolysis of the (R)- and (S)-cyanohydrins is treated directly with an aromatic hydrocarbon, optionally in combination with a cosolvent, and is then extracted at hydrolysis temperature, whereupon after cooling of the organic phase the corresponding chemically and optically highly pure (R)- and (S)-&agr;-hydroxycarboxylic acids having an optical purity of over 98%ee crystallize out.

Process for the preparation of optically and chemically highly pure (R)- or (S)-&agr;-hydroxycarboxylic acids

The invention relates to the production of (R)-enantiomeric, optically active cyanohydrins by reacting an aldehyde or a ketone with a cyanide group donor in the presence of (R) oxynitrilase, wherein a reaction mixture comprising a) an aldehyde or a ketone dissolved in an organic solvent; said organic solvent is immiscible or only slightly miscible with water, b) any aqueous R)-oxynitrilase solution and c) a cyanide group donor is stirred in such away that an emulsion is formed which remains intact until the end of the enzymatic reaction. After the enzymatic reaction has terminated, the (R)-cyanohydrin is isolated from the reaction mixture.

Method for the production of optically active cyanohydrins using r-oxynitrilase

A process for the preparation of enantiomer-enriched aminofuranones and hydroxyfuranones in which an enantiomer-enriched cyanohydrin is acylated by an acylating agent, then cyclized at 40 to 90&deg; C. in the presence of zinc or a zinc compound to the corresponding enantiomer-enriched aminofuranone, which is converted where appropriate by acid hydrolysis into the corresponding enantiomer-enriched hydroxyfuranone.

Process for preparing enantiomer-enriched amino- and hydroxyfuranones

Process for the stereoselective reduction of chiral &agr;- or &bgr;-keto esters which have a chiral center in the &ggr; position in an inert solvent at temperatures from &minus;80 to &plus;50&deg; C. using a reductant obtained by reaction of NaBH and (D)- or (L)-tartaric acid, to give the corresponding diastereomeric hydroxy compounds in each case.

Growing community of inventors

Linz, Austria

Peter Pöchlauer

Growing community of inventors

Linz, Austria

Peter P&ouml;chlauer

Peter Pöchlauer