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Case Law of the Boards of Appeal

5.1.3 Novelty of enantiomers

According to decision T 296/87 (OJ 1990, 195), the description of racemates did not anticipate the novelty of the spatial configurations contained in them; racemates were described in the state of the art by means of expert interpretation of the structural formulae and scientific terms; as a result of the asymmetric carbon atom contained in the formula the substances concerned might occur in a plurality of conceivable spatial configurations (D and L enantiomers), but the latter were not by themselves revealed thereby in an individualised form. That methods exist to separate the racemate into enantiomers was something that should only be considered with respect to inventive step.

In T 1048/92 the board observed that the fact that the disclosure of the prior document did not embrace more than two possible steric configurations did not take away the novelty of the specific one which was claimed in the application, because there was no unambiguous technical teaching directed to that configuration. The novelty of such an individual chemical configuration could only be denied if there was an unambiguous disclosure of this very configuration in the form of a technical teaching. It was thus not sufficient that the configuration in question belonged conceptually to a disclosed class of possible configurations without any pointer to the individual member.

In T 1046/97 the claim was directed to a specific pure enantiomer. The examining division found that prior art document (B) disclosed a compound of the same formula as the one claimed by the applicant but without giving any information on its stereochemical configuration. However, in document (B) it was also stated that "all optically active forms of the compounds described therein were enclosed in the teaching thereof." Since it belonged to the skilled person's general knowledge to identify such mixtures and to separate them, in the examining division's view the claimed enantiomer was not novel.

The board saw no reason to believe that a skilled person would not combine the disclosure of that compound with the reference to the racemic, meso and optically­active forms. However, it was established case law of the boards of appeal that the novelty of an individual chemical compound could only be denied if there was a direct and unambiguous prior disclosure of this very compound in the form of a technical teaching (see T 181/82, OJ 1984, 401; T 296/87, OJ 1990, 195). It was thus not sufficient to show lack of novelty, that the claimed enantiomer belonged conceptually to the group of possible optically­active forms mentioned in document (B), unless there was a pointer to the individual member of the group at stake. Thus, the claimed specific enantiomer being incontestably neither a racemate nor a meso form, the assessment of novelty crystallised on the question, whether it was directly and unambiguously derivable from the disclosure of the compound when combined with the reference to the optically active forms.

The board held that the term "optically­active forms" was to be interpreted as embracing any stereochemical form of the compounds disclosed in document (B), independently of whether such property was obtained by a pure stereochemical isomer or by any mixture of such isomers. Since document (B) provided no information about any specific stereochemical form this disclosure must be regarded as undifferentiated, with the effect that the reference to "all optically active forms of the compounds described therein" could not be equated to an individualised disclosure of a specific enantiomer. The board thus held that the specific configuration of the claimed enantiomer was not directly and unambiguously derivable from the teaching of document (B) and that novelty had not been destroyed.