Alpha-aminophosphonates Class Of Chiral Compounds By High Performance Liquid Chromatography (hplc) Separation And Preparation

The enantiomeric resolution by HPLC is important to contemporary synthetic chemistry,medicinal and agricultural chemistry etc.Chiral solid phase(CSP) is the key factor for direct enantiomeric resolution.Polysaccharide based stationary phase has been identified as versatile and useful CSP for the separation of enantiomers.Three CSPs derived from polysaccharide stationary phase(Chiralcel OD-H, Chiralpak AD-H and Chiralpak IA) were compared for the enantioseparation ofα-aminophosphonate derivatives.The effects of compound structure,column temperature,polar modifier and its concentration on the resolution were investigated by chromatographic parameters such as retention factor(k),separation factor(α) and resolution(Rs).Chiralpak IA column was selected for the semi-preparative separation of a series ofα-aminophosphonate derivatives with normal phases,which is a new immobilized CSP based on 3,5-dimethylphenylcarbamate of amylose.It was found that different CSPs displayed different enantioselectivities.Even the same CSP was shown to differ in the ability to cause enantiomeric separation due to the different preparation techniques involved.The chiral separation strongly depends on the structure of solutes,the composition of mobile phase,organic modifier concentration and the column temperature.Semi-preparative separation of 18 racemates was executed successfully on Chiralpak IA column and 36 pure enantiomers were obtained.The enantiomeric excess values of most of pure enantiomers were more than 98%.Some pure optical isomers were confirmed by ¹H NMR.Single crystal of compound(-)-a₃-I was confirmed and structure was found to possess an S configuration by X-ray diffraction. The bioactivity of all compounds prepared were tested preliminarily,the results indicated(+) and(-) enantiomers exhibit little different anti-tobacco mosaic virus(TMV) activities.