Design And Synthesis Of Chiral Solvating Agent And Pattern-based Recognition For Determination Of Enantiomeric Excess Using NMR

The NMR is an important and useful tool in chiral recognition. Theutility model has obviously advantages: the product without separationand purification, be rapidly determinated, and environment friendly. Inthis paper, a series research has been done focus on the theme. The thesiscan be divided into the following parts:1. A series of chiral salan C2-symmetric aminophenols1-7, whichwere derived from (1R,2R)-or (1S,2S)-1,2-diphenylethane-1,2-diaminewith the corresponding salicylic aldehyde through a [2+2] condensationreaction, have been prepared. The NMR studies demonstrated that theycan function as chiral solvating agents for the determination of theenantiomeric purity of chiral α-hydroxy carboxylic acids.2. A protocol for the determination of enantiomeric excess of chiraldrug, such as Lansoprazole, using the subtle frequency shifts (chemicalshift perturbation) in NMR spectra induced by chiral auxiliaries(R-Binol,quinidine, cinchonine), is described. The spectra were analyzed with twopattern recognition protocols. Principal component analysisdemonstrated good enantioselective separation of the analytes, andpartial least-squares was used to analyze ee. values of unknown samples.We believe that this method combines several attractive features: itdepends on commercially accessible chiral auxiliaries that arenonspecific, avoids substrate derivatization and minimizes solvent waste,and it supplies a new method for determing the chiral purity of chiraldrugs. Therefore, this result provides a new insight to refining andexpanding the applications of existing chiral solvating agents for enantioselective analysis.