Method of preparing optically active cyanohydrin derivatives
AssigneeDuphar International Research B.V.
InventorsJohannes Brussee, Arne Van Der Gen, Erwin G. J. C. Warmerdam, Chris G. Kruse
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Abstract
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.
Claims4
A method of preparing an optically active cyanohydrin derivative from an optically active organohydrin of opposite configuration, comprising the steps of converting an optically active cyanohydrin of the general formula ##STR9## wherein:
- R.sub.2 ' is a phenyl group, which group may be substituted with 1-3 substituents selected from the group consisting of halogen, (C.sub.1 -C.sub.4)alkyl, nitro, (C.sub.1 -C.sub.4)haloalkyl, phenyl, phenoxy and cyano;
- or wherein
- R.sub.2 ' is a pyridyl group;
- or wherein
- R.sub.2 ' is a vinyl group, which group may be substituted with (C.sub.1 -C.sub.4)alkyl, phenyl or substituted phenyl, wherein the substituents are selected from the above-defined group;
- by reaction with a carboxylic acid of the general formula ##STR10## wherein:
- R.sub.1 is straight or branched (C.sub.1 -C.sub.6)alkyl group, a cyclohexyl group, or a methyl group substituted with (C.sub.1 -C.sub.4)alkoxy, phenyl, diphenyl or substituted phenyl, wherein the substituents are selected from the group consisting of methyl, methoxy, chloro, fluoro, trifluoromethyl, cyano and nitro;
- or wherein
- R.sub.1 is an aryl or heteroaryl group, selected from the group consisting of phenyl, naphthyl, furyl, pyridyl, quinolyl, thienyl and pyrrolyl, which group is optionally substituted with 1 to 3 substituents selected from the group consisting of methyl, methoxy, trifluoromethyl, cyano and nitro, or with 1 to 5 halogen substituents;
- or wherein
- R.sub.1 is a group of the formula ##STR11## wherein:
- R.sub.4, R.sub.5 and R.sub.6 are each independently (C.sub.1 -C.sub.4)alkyl, phenyl or phenyl substituted with one or more substituents selected from methyl, methoxy, nitro, halogen and cyano;
- or wherein R.sub.4 is methyl, and R.sub.5 plus R.sub.6, together with the C-atom to which they are attached, constitute a cyclohexyl group;
- or wherein R.sub.4, R.sub.5 plus R.sub.6, together with the C-atom to which they are attached, constitute an adamantyl or bicyclooctyl group
- in the presence of a di(C.sub.1 -C.sub.4)alkyl azodicarboxylate and a triphenylphosphine, to produce an optically active cyanohydrin carboxylic acid ester of opposite configuration in high enantiomeric purity, having the general formula ##STR12## wherein the symbols have the above meanings.
Dependencies are inferred from the claim text.