Chen Li-ren

Direct optical resolution of the enantiomers of axially chiral compounds by high-performance liquid chromatography on cellulose tris-(3,5-dimethylphenylcarbamate) stationary phase

SummaryThe enantiomeric separation of nineteen biphenyl dimethyl dicarboxylate derivatives has been examined by HPLC on a chiral statonary phase prepared by coating aminopropylated silica gel with cellulose tris-(3,5-dimethylphenylcarbamate). It was found that trifluoroacetic acid (TFA) has a dominant effect on chiral separation for acidic compounds. The percentage of 2-propanol in the mobile phase does not have a large effect on the anantioselectivity but the separation was dramatically influenced by the kind of alcohol in the mobile phase. The effect of temperature on the chiral separation is also discussed. Most of the enantiomers investigated could be resolved satisfactorily.

Enantioseparation of Novel Chiral Tetrahedrane-Type Clusters on an Amylose Tris (Phenylcarbamate) Chiral Stationary Phase

SummaryAmylose tris(phenylcarbamate) (ATPC) coated on a small particle silica gel was prepared. This ATPC chiral stationary phase (ATPC-CSP) was found to be useful for the enantiomeric separation of some novel chiral tetrahedrane-type clusters. Moreover, the influence of mobile phase modifier and of the structure of chiral tetrahedrane-type clusters on the chiral separation and retention were investigated. The results suggest that not only the structure and concentration of alcohol in mobile phase, but also the subtle structural differences in racemates can have a pronounced effect on enantiomeric separation and retention.

HPLC resolution of the enantiomers of glycidyl sulfides and glycidyl selenides on amylose tris-(phenylcarbamate) stationary phase

SummaryThe resolution of the enantiomers of a series of glycidyl sulfides and glycidyl selenides has been examined on a chiral stationary phase prepared by coating aminopropylated silica gel with amylose tris-(phenylcarbamate). Most of the enantiomers of glycidyl monosulfides and monoselenides could be resolved satisfactorily but those of the disulfides could not. The effects of solute structure and of the concentration of 2-propanol in the mobile phase on retention and resolution were investigated.

Optical resolution of glycerin sulfides and glycerin selenides on the chiral stationary phase of cellulose-tris(3, 5-dimethylphenylcarbamate)

Cellulose-tris(3,5-dimethylphenylcarbamate) was prepared after a reported method and was coated onto an aminopropylated mesopore spherical silica gel. The final product was used as a chiral stationary phase of high performance liquid chromatography for the enantioseparation of a series of glycerin sulfides and glycerin selenides. Mixtures of hexane and 2-propanol were used as mobile phases. The effects of 2-propanol concentration in the mobile phase on the retention and resolution were investigated. Some enantiomers of the glycerin monosulfides and monoselenides could be separated satisfactorily, but none of the disulfides could be separated. The structural features of the solutes that influence chiral separation were discussed. Copyright 1999 Wiley-Liss, Inc.

Direct Chiral Separation of Four Indole Derivatives by High Performance Liquid Chromatography with Chiral Stationary Phase

Abstract A chiral stationary phase (CSP) was prepared by coating cellulose-tris(3,5-dimethylphenyl carbamate) (CDMPC) onto spherical silica gel. Four newly synthesized chiral indole derivatives were directly resolved on the CDMPC-CSP by a normal-phase system. The influences of structure and proportion of the alcohol in mobile phases on the separation by high-performance liquid chromatography with chiral stationary phase (HPLC) were investigated to optimize the chromatographic conditions. N-butano1, ethanol and ethanol were suitable for the separation of sample I, III, and IV as the modifiers, respectively, whereas the mixture of ethanol and n-propanol was suitable for sample I. Under the optimal conditions, excellent enantioseparation was achieved and the enantiomer excess values of all the four samples were determined. The satisfactory results indicated that the method of HPLC is ideal for the separation of indole derivatives.