Riedel-de Haen Aktiengesellschaft

Cassella Aktiengesellschaft

Horst Schmand

Wolfgang Dannenberg

Gunter Bartels

Bernd Kellermeier

Hans-Jurgen Schmidt

The present invention relates to a process for the preparation of compounds of the general formula I ##STR1## in which X and Y, independently of each other, represent hydrogen, fluorine, chlorine or bromine, but cannot simultaneously represent hydrogen, characterised in that compounds of the general formula II ##STR2## in which X and Y are defined as above, are reacted with aqueous ammonia under copper catalysis, and to intermediates for the preparation of compounds of the general formula I.

Process for the preparation of haloanthranilic acids

In the process for the preparation of fluorinated benzoic acids of the formula I ##STR1## in which X and Y, for example, independently of one another denote chlorine or fluorine and X moreover denotes bromine, a fluorinated chloroacetophenone of the formula II ##STR2## in which Z denotes chlorine or hydrogen, is reacted with a hypohalite.

Process for the preparation of fluorinated benzoic acids

In a process for resolving racemic DL-.alpha.-aminocarboxylic acids the said acids are reacted in an inert solvent with an aromatic o-hydroxy aldehyde to obtain an azomethine derivative which is reacted in the same stage with an optically active amine base to give a salt. The diastereomeric salt obtained is separated and the respective optically active .alpha.-aminocarboxylic acid is obtained therefrom by an acid treatment. By this process aliphatic and aromatic .alpha.-amino-carboxylic acids can be resolved, especially p-hydroxyphenyl glycine.

Process for resolution of racemic DL-.alpha.-aminocarboxylic acids

Optically active 2-amino-2-phenylacetic acid of the formula ##STR1## in which R.sub.1, R.sub.2 and R.sub.3, which are identical or different, denote hydrogen, halogen, hydroxy, alkyl, acyl, or alkoxy, is prepared by asymmetrical transformation of a corresponding DL-aminophenylacetonitrile with L(+)-tartaric acid. To this end the corresponding DL-2-amino-2-phenyl-acetonitrile is reacted with approximately equimolar amounts of L(+)-tartaric acid in the presence of at least one alkanol having from 1 to 5 carbon atoms and/or at least one carbonyl compound at a temperature of from 0.degree. to 50.degree. C. and the mixture is stirred for 2 to 120 hours at the indicated temperature. The crystallized transformation product is separated, hydrolyzed by treatment with an acid and the desired product is isolated.

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Bad Nenndorf, Germany

Horst Schmand