Raeso-Tartaric acid

Draw the structure of raeso-tartaric acid (2,3-dihydroxybutanedioic acid) with an anticlinal conformation in a sawhorse projection. 

Which symmetry elements are present in raeso-tartaric acid ... 

In order to ascertain which symmetry elements are present in raeso-tartaric acid, it is necessary to look at the various conformations of the molecule. The symmetrical highest energy conformer, i.e. the synperiplanar conformer (sp), has a plane of symmetry in which both enantiomorphic halves of the molecule are reflections of each other. No other symmetry elements are present in this conformation (point group Cs). In the ap conformation of raeso-tartaric acid the only symmetry element present is a centre of symmetry (disregarding the fact that the centre of symmetry is equivalent to any of the infinite number of S2 axes). The symmetry point group is therefore Cj. All other conformations, e.g. the +synclinal conformation (+sc) of raeso-tartaric acid shown below, are chiral and do not possess any symmetry elements and therefore belong to the point group C. ... 

Another study investigated the final products of the degradation of HA [262] It was shown that the NaOCl oxidation of HA yields primarily raeso-tartaric acid. In contrast, arabinaric acid and glucaric acid are obtained by the oxidation of HA with the Fenton reagent. It was suggested that meso-tartaric acid might be a useful biomarker of HA oxidation since it is produced by both NaOCl and Fenton chemistry. 

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