U.S. Patent No. 5,532,372, directed to imide compounds.

The claim recited a molecular structure argued to be a racemic mixture (50-50) of two enantiomers based on similarity to a compound in the specification (page 6).  The plain claim language and specification indicate that the claim at least covers the (-)enantiomer (pages 7-8).  The specification does not infer a disclaimer of other than racemic or even use the term racemic, so there is no teaching that the claimed molecule should be considered racemic (pages 9-12).  Since the alleged infringer also includes this (-) enantiomer, there is infringement (pages 2-3).

Hindsight: Chemistry is beyond me, but it appears that including a discussion of racemic in the specification and specific indication of the claimed molecule as not being racemic or including racemic and non-racemic would have helped.