31. Chemically, levocetirizine is the active enantiomer of cetirizine. 32. This reaction delivers one enantiomer with 88 % ee. 33. Polarimetry may therefore be applied for concentration measurements of enantiomer -pure samples. 34. The reaction step creates two stereocenters leading to two diastereomeric pairs of enantiomers . 35. Similarly, replacement of one or the other with deuterium will generate enantiomers . 36. Conversely, two compounds that are enantiomers have the same NMR spectral properties. 37. The latter two clearly refer to the two enantiomers . 38. It has been reported that the two enantiomers had different toxicokinetics and toxicity. 39. The stationary phase is itself chiral and forms complexes selectively with the enantiomers . 40. Both enantiomeric products could be obtained by using different enantiomers of the catalyst.
