Indirect enantioseparation of alpha-amino acids by reversed-phase liquid chromatography using new chiral derivatizing reagents synthesized from s-triazine chloride.
Ten chiral dichloro- and monochloro-s-triazines were prepared by the nucleophilic displacement of chlorine atom(s) in s-triazine chloride and its 6-methoxy derivative with different amino acid amides. Dichloro-s-triazines (DCTs) were used as CDRs for derivatization of alpha-amino acids under basic conditions at room temperature (30 degrees C) while derivatization with monochloro-s-triazine (MCT) reagents was carried out at 80 degrees C. The resultant diastereomers were separated on a reversed-phase C(18) column using mixtures of acetonitrile and aqueous-trifluoroacetic acid (TFA). The separation results for the two were compared. One DCT reagent was optimized for derivatization kinetics with respect to the effects of pH, reagent excess, temperature and reaction time on derivatization yield. In most of the cases, DCT reagents provided better separation of diastereomers in comparison to MCT reagents. One DCT reagent was also validated for limit of detection, linearity, recovery and robustness. Effects of structural modifications in reagents on chromatographic properties were investigated. Separation mechanism of diastereomers was proposed in light of both MCT and DCT reagents.
Bhushan
Ravi
R
Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247667, India. rbushfcy@iitr.ernet.in
Kumar
Virender
V
D000596:Amino Acids / Q000138:chemical synthesis / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D007700:Kinetics; D012680:Sensitivity and Specificity; D014227:Triazines / Q000138:chemical synthesis / Q000737:chemistry*
D000596:Amino Acids; D014227:Triazines