高效液相色谱手性固定相对有机膦酸酯类对映体分离研究

Studies on Separation of Organic Phosphonate Enantiomers on Chiral Stationary Phase by High Performance Liquid Chromatography

利用Ｐｉｒｋｌｅ型手性固定相系统地研究了１１种有机膦酸酯的手性分离情况。讨论了流动相中强组分异丙醇浓度和柱温对手性分离的影响。结果表明，手性分离系数随温度的升高和流动相中强组分浓度的增加而降低。讨论了有机膦酸酯不同取代基对手性分离的影响，指出手性分离中取代基位置的不同会直接影响手性分离结果，空间位阻过大同样会使手性分离系数降低。在选定的分离条件下，１１种有机膦酸酯均可达到基线分离。根据手性分离结果给出了可能的手性分离机理。

The enantiomers of eleven chiral organic phosphonates have been separated on Pirkle type chiral stationary phase ( N 3,5 dinitrobenzoyl L leucine aminopropyl silica gel) using mixture of isopropyl alcohol and hexane as mobile phase. The influences of the isopropyl alcohol content in mobile phase (2%, 5%, 10%,15%) and column temperature (20 40℃) on the retention and enantioselectivity have been investigated. The capacity factor k ′ and separation factor α of all solutes were decreased with increasing the isopropyl alcohol content and the column temperatures, but the dependence on temperature was not significant. The capacity factor k ′ and separation factor α were varied with the substituent in different positions. The separation of compounds No. 1 4 was the easiest and baseline separation occurs over the concentration of 5% 15% isopropyl alcohol in mobile phase. The baseline separation of compounds No. 5 9 was obtained when the concentration of isopropyl alcohol in mobile phase was 10% or lower. Only when the concentration of isopropyl alcohol in mobile phase was 2% or lower, the baseline separation of compounds No. 10 11 could be obtained. High stereo hinder substituent (R 2= i Pr, compounds No. 10 and 11) decreased the capacity factor k ′ and separation factor α . A possible chiral recognition mechanism is proposed. The enantioselectivity depends strongly upon the nature, position and size of substituents R 1 and R 2 of the organic phosphonate compounds.