Duphar International Research Bv

Johannes Brussee

Arne Van Der Gen

Chris G Kruse

Cornelis G Kruse

Erwin G Warmerdam

The invention relates to a method of preparing an optically active cyanohydrin carboxylic acid ester from an optically active cyanohydrin of opposite configuration, wherein said starting cyanohydrin is converted with a carboxylic acid in the presence of a dialkyl azodicarboxylate and a triarylphosphine. The invention also relates to a method of preparing an optically active cyanohydrin of opposite configuration by a subsequent solvolysis of the ester obtained under conservation of the configuration.

Method of preparing optically active cyanohydrin derivatives

The present invention is concerned with the preparation of N-substituted vicinal aminoalcohol derivatives from the corresponding hydroxyl-protected cyanohydrin derivatives by successive partial reduction, transimination using a primary amine, reduction of the resulting imine and optional removal of the hydroxyl-protecting group. The products are obtained either as a racemate or in an optically pure form, depending upon the stereochemical composition of the starting cyanohydrin derivatives. The present invention is also concerned with certain new enantiomerically pure hydroxyl-protected vicinal aminoalcohols.

Method of preparing vicinal aminoalcohols

The invention relates to a method of preparing optically active alcohols which consist substantially (at least 75% e.e.) or entirely of one enantiomer of formula 4 ##STR1## wherein R and A are as defined therein. The method comprises, which maintaining enantiomeric excess, converting an optically active cyanohydrin of formula 1 ##STR2## into optically active protected cyanohydrin of formula 2 ##STR3## converting the protected cyanohydrin of formula 2 into an optically active compound of formula 3 ##STR4## removing the protecting group B.

Method of preparing optically active alcohols which consist

The present invention is concerned with the preparation of erythro N-substituted vicinal aminoalcohol derivatives from hydroxyl-protected cyanohydrin derivatives by successive Grignard reaction, transimination using a primary amine, reduction of the resulting imine and removal of the hydroxyl-protecting group. The products are obtained either as a racemate or in an optically pure form, depending upon the stereochemical composition of the cyanohydrin derivatives.

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Weesp, Netherlands

Johannes Brussee