Lee Wonjae, Bang Eunjung, Baek Chae-Sun, Lee Weontae
College of Pharmacy, Chosun University, 375 Seoseok-Dong, Dong-Ku, Kwangju 501-759, Republic of Korea.
Magn Reson Chem. 2004 Apr;42(4):389-95. doi: 10.1002/mrc.1353.
Chiral discrimination studies using (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid (18-C-6-TA) as a chiral selector were performed by high-performance liquid chromatography (HPLC) and NMR spectroscopy. The enantiomers of alanine (Ala) or alanine methyl ester (Ala-ME) were well separated on the chiral stationary phases (CSPs) derived from (+)-18-C-6-TA by HPLC. The chiral selector, (+)-18-C-6-TA, used in the CSP was also applied for the chiral discrimination of the Ala and Ala-ME enantiomers, and it discriminated these enantiomers successfully by NMR spectroscopy. The chemical shift differences (Delta Delta delta) of the alpha-proton of these enantiomers in the presence of an equimolecular solution of 18-C-6-TA were observed to be 0.10 ppm for Ala in methanol-d4 containing 10 mM H2SO4 and 0.11 ppm for Ala-ME in methanol-d4. The observed NMR results agreed with the chromatographic data on the (+)-18-C-6-TA-derived CSP by HPLC in terms of both the elution order and solvents effects.
采用高效液相色谱（HPLC）和核磁共振波谱法进行了以（+）-（18-冠-6）-2,3,11,12-四羧酸（18-C-6-TA）作为手性选择剂的手性识别研究。通过HPLC在由（+）-18-C-6-TA衍生的手性固定相（CSP）上，丙氨酸（Ala）或丙氨酸甲酯（Ala-ME）的对映体得到了很好的分离。用于CSP的手性选择剂（+）-18-C-6-TA也被应用于Ala和Ala-ME对映体的手性识别，并且通过核磁共振波谱法成功地鉴别了这些对映体。在含有18-C-6-TA等分子溶液的情况下，这些对映体的α-质子的化学位移差值（Δδ）在含10 mM H2SO4的氘代甲醇-d4中，Ala为0.10 ppm，在氘代甲醇-d4中Ala-ME为0.11 ppm。观察到的核磁共振结果在洗脱顺序和溶剂效应方面与通过HPLC在由（+）-18-C-6-TA衍生的CSP上的色谱数据一致。
