| The NMR is a very important method in chiral analysis. The utilitymodel has obviously advantages: the product without separation andpurification, rapidly determined, and environment friendly. Some workwas done on the subject in this thesis; the main contents can be dividedinto three parts:1. Chiral derivatization protocols of three components are proposedfor the enantiomeric recognition of chiral hydroxy acids using1H NMR.The protocols involve simply mixing of2-formyl phenyl boronic acid,primary amines and chiral hydroxy acids in CDCl3, followed by5minutes stirring. The spectra could be recorded directly, without invokingany separation method, unlike required by many other chiral derivatizingagents. The method is direct, simple and rapid, etc..2. The chiral recognition of racemic ibuprofen drugs by thiourea wasstudied by1H NMR spectroscopy. A ternary complex could be formed bychiral thiourea and ibuprofen with the participation of DMAP, excellentenantiodiscrimination based on well-resolved α-H NMR signals of theenantiomers of ibuprofen can be obtained without interference from thechiral bisthiourea and DMAP. So chiral thiourea would be a good chiralsolvating agent. To check the ability of the chiral bisthiourea/DMAP forenantiomeric determination, the ee. values of ibuprofen samples over awide range were determined by integration of the α-H signal of ibuprofenin1H NMR, and the results coincide with the theoretical value.3. A novel chiral solvating agent with strong shielding effect andmany binding sites was obtained by the reaction of R-Binol with chiralamino alcohols. The compound was an effective chiral solvating agent compared to others. The recognition results of carboxylic acids, includingalkyl acids and aryl acid, were very well. The measurements of1Hchemical shift nonequivalences(ΔΔδ) was258Hz with the molar ratio of2:1.Summary: The study broadens the application of NMR for theanalysis of chiral carboxylic acid. |
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