Abstract: A process is disclosed for preparing an (S)-2-amino-&ohgr;-oxoalkanoic acid derivative in which the corresponding aldehyde is converted into the corresponding acetal-protected aldehyde, the acetal-protected aldehyde is converted into the corresponding aminonitrile, the aminonitrile is converted into the corresponding amino acid amide, the amino acid amide is subjected to an enzymatic, enantioselective hydrolysis in which the (R)-enantiomer of the amino acid amide remains and the (S)-enantiomer is converted into the (S)-amino acid, and the (S)-amino acid is isolated. Preferably, the reaction mixture obtained after the conversion of the aminonitrile into the amino acid amide is treated with a benzaldehyde to form the Schiff base of the amino acid amide. The Schiff base is separated out and is converted into the free amino acid amide.

Abstract: A diastereomer complex obtained via a process for the separation of enantiomers is disclosed, wherein separation can be rapidly effected such that enantiomers are obtained with high e.e. values. The process permits the separation of mixtures of enantiomers in which more than one resolving agent is used, of which at least one resolving agent is optically active, and which yields a diastereomer complex containing at least two resolving agents in optically active form. The process provides for, inter alia, a diastereomer complex having at least three compounds of which at least two compounds are resolving agents in optically active form, and at least one compound is an enantiomer in optically active form. Also provided is a diastereomer complex having at least three compounds of which at least one compound is a resolving agent in optically active form, and at least two compounds which are enantiomers in optically active form.

Abstract: A diastereomer complex obtained via a process for the separation of enantiomers is disclosed, wherein separation can be rapidly effected such that enantiomers are obtained with high e.e. values. The process permits the separation of mixtures of enantiomers in which more than one resolving agent is used, of which at least one resolving agent is optically active, and which yields a diastereomer complex containing at least two resolving agents in optically active form. The process provides for, inter alia, a diastereomer complex having at least three compounds of which at least two compounds are resolving agents in optically active form, and at least one compound is an enantiomer in optically active form. Also provided is a diastereomer complex having at least three compounds of which at least one compound is a resolving agent in optically active form, and at least two compounds which are enantiomers in optically active form.

Abstract: A process is disclosed for preparing an (S)-2-amino-&ohgr;-oxoalkanoic acid derivative in which the corresponding aldehyde is converted into the corresponding acetal-protected aldehyde, the acetal-protected aldehyde is converted into the corresponding aminonitrile, the aminonitrile is converted into the corresponding amino acid amide, the amino acid amide is subjected to an enzymatic, enantioselective hydrolysis in which the (R)-enantiomer of the amino acid amide remains and the (S)-enantiomer is converted into the (S)-amino acid, and the (S)-amino acid is isolated. Preferably,the reaction mixture obtained after the conversion of the aminonitrile into the amino acid amide is treated with a benzaldehyde to form the Schiff base of the amino acid amide. The Schiff base is separated out and is converted into the free amino acid amide.

Abstract: A diastereomer complex obtained via a process for the separation of enantiomers is disclosed, wherein separation can be rapidly effected such that enantiomers are obtained with high e.e. values. The process pets the separation of mixtures of enantiomers in which more than one resolving agent is used, of which at least one resolving agent is optically active, and which yields a diastereomer complex containing at least two resolving agents in optically active form. The process provides for, inter alia, a diastereomer complex having at least three compounds of which at least two compounds are resolving agents in optically active form, and at least one compound is an onantiomer in optically active form. Also provided is a diastereomer complex having at least three compounds of which at lea one compound is a resolving agent in optically active form, and at least two compounds which are enantiomers in optically active form.

Abstract: A process is disclosed for preparing an (S)-2-amino-&ohgr;-oxoalkanoic acid derivative in which the corresponding aldehyde is converted into the corresponding acetal-protected aldehyde, the acetal-protected aldehyde is converted into the corresponding aminonitrile, the aminonitrile is converted into the corresponding amino acid amide, the amino acid amide is subjected to an enzymatic, enantioselective hydrolysis in which the (R)-enantiomer of the amino acid amide remains and the (S)-enantiomer is converted into the (S)-amino acid, and the (S)-amino acid is isolated. Preferably, the reaction mixture obtained after the conversion of the aminonitrile into the amino acid amide is treated with a benzaldehyde to form the Schiff base of the amino acid amide. The Schiff base is separated out and is converted into the free amino acid amide.

Abstract: A process is disclosed for preparing an (S)-2-amino-.omega.oxoalkanoic acid derivative in which the corresponding aldehyde is converted into the corresponding acetal-protected aldehyde, the acetal-protected aldehyde is converted into the corresponding aminonitrile, the aminonitrile is converted into the corresponding amino acid amide, the amino acid amide is subjected to an enzymatic, enantioselective hydrolysis in which the (R)-enantiomer of the amino acid amide remains and the (S)-enantiomer is converted into the (S)-amino acid, and the (S)-amino acid is isolated. Preferably, the reaction mixture obtained after the conversion of the aminonitrile into the amino acid amide is treated with a benzaldehyde to form the Schiff base of the amino acid amide. The Schiff base is separated out and is converted into the free amino acid amide.

Abstract: The invention relates to a process for preparing optically active methionine amide in high ee purities in which a mixture of D- and L-methionine amide or the Schiff bases thereof is at least partly converted, optionally in the presence of 0.5-4 equivalents of an aldehyde, relative to the amount of methionine amide, and water, in the presence of an organic solvent, using less than 1.2 equivalents of L- or D-mandelic acid, respectively, relative to the amount of D- or L-methionine amide, respectively, or the Schiff bases thereof, present in the mixture of D- and L-methionine amide or the Schiff bases thereof, into a salt of methionine amide and mandelic acid, a portion consisting substantially of one of the diastereoisomers of the salt is separated from the reaction mixture obtained, and the salt is converted into the optically active methionine. A high degree of optical purity is obtained.

Abstract: The invention relates to a method for the preparation of an .alpha.,.alpha.-disubstituted .alpha.-amino alcohol from the corresponding amide with the aid of sodium in the presence of an alcohol as solvent. The conversion of amino acid amide to amino alcohol proceeds virtually quantitatively. Moreover, the reduction of the amino acid amide to the corresponding amino alcohol proceeds with retention of optical activity.