NMR.‐spektroskopische Methoden als Reinheitskriterien isomerer Weinsäuren und Weinsäureester

NMR.‐spectroscopic Methods as Criteria of the Purity of Isomeric Tartaric Acids and Their Esters meso ‐Tartaric acid ( 2 ) can be distinguished either from the natural (+)‐(2 R , 3 R )‐tartaric acid ( 1 ) or the ‘unnatural’ (−)‐(2 S , 3 S )‐tartaric acid ( 1 ′) or their racemic mixture, by 1 H‐NMR.‐spectral resolution using europium chloride in aqueous solution. Diastereomeric esters have been prepared from different esters of tartaric acid 3 and the Mosher reagent 4 and the purities of the enantiomers of 3 have been checked by 1 H‐NMR. spectroscopy.