Process for the preparation of optically active carboxylic acids and amide intermediates
AssigneeConsortium fur Elektrochemische Industrie GmbH
InventorElke Fritz-Langhals
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Abstract
The present invention provides a process for the preparation of optically active carboxylic acids of the formula I* or II* ##STR1## in which X is an oxygen or sulfur atom and n is 1 or 2. The process comprises reacting a racemic carboxylic acid I or II or its derivatives with an optically active 2-amino-carboxylic acid ester to give the diastereomeric carboxylic acid amides, separating the diastereomers and, after cleavage of the amide bond, isolating the optically active carboxylic acids of the general formula I* or II*. The invention also provides certain novel optically active carboxylic acid amides and a tetrahydrothiopyran-2-carboxylic acid.
Claims24
A process for the preparation of optically active carboxylic acids of the formula I* or II* ##STR9## in which X is an oxygen or sulfur atom and n is 1 or 2, which comprises reacting a racemic carboxylic acid I or II or its derivatives, wherein said derivatives are selected from the group consisting of acid halides, esters, anhydrides and amides, with an optically active 2-aminocarboxylic acid ester to give the diastereomeric carboxylic acid amides, separating the diastereomers and, after cleavage of the amide bond, isolating the optically active carboxylic acids of the general formula I* or II*.
Optically active carboxylic acid amides of the formula IV* or V* ##STR14## wherein n=1 or 2, X.dbd.S or O, R is --CH.sub.3, --CH(CH.sub.3).sub.2, --CH.sub.2 CH(CH.sub.3).sub.2, --CH.sub.2 CH.sub.2 SCH.sub.3, or a benzyl radical, and R' is --CH.sub.3, --CH.sub.2 OCH.sub.3 , --CH.sub.2 CH.sub.3, --CH.sub.2 CH.sub.2 CH.sub.3 or --CH(CH.sub.3).sub.2.
Dependencies are inferred from the claim text.