Characterization of highly sulfated cyclodextrins.

Area of Science:

• Analytical Chemistry
• Separation Science
• Carbohydrate Chemistry

Background:

• Chiral compound separation is crucial in pharmaceuticals and chemical industries.
• Cyclodextrins are widely used as chiral selectors in capillary electrophoresis (CE).
• Developing novel cyclodextrin derivatives with enhanced chiral recognition properties is an ongoing research area.

Purpose of the Study:

• To develop and characterize highly sulfated cyclodextrins (HS-CDs) for enantiomeric separation.
• To investigate the structural features of HS-CDs influencing chiral selectivity.
• To evaluate the efficacy of HS-CDs as chiral selectors in capillary electrophoresis (CE) for diverse chiral compounds.

Main Methods:

• Facile single-step direct sulfation of cyclodextrins using sulfur trioxide-trimethylamine complex.
• Characterization using electrospray ionization mass spectrometry (ESI-MS) and capillary electrophoresis (CE).
• 13C Nuclear Magnetic Resonance (NMR) spectroscopy for structural elucidation and elemental analysis for sulfate content determination.

Main Results:

• Synthesized HS-CDs with narrow heterogeneity in sulfation degree.
• Determined average sulfate content per molecule for HS-alpha-, beta-, and gamma-CDs (11, 12, and 13, respectively).
• Demonstrated effective enantiomeric separation of neutral, acidic, and basic chiral compounds using HS-CDs as chiral selectors in CE, with complementary selectivities among HS-alpha-, beta-, and gamma-CDs.

Conclusions:

• The regiospecific sulfation pattern of HS-CDs, particularly at C-2 and C-6 positions, is key to their chiral recognition capabilities.
• HS-CDs provide differential diastereoisomeric complexation, enabling efficient resolution of racemates.
• These novel HS-CDs represent a versatile and effective class of chiral selectors for capillary electrophoresis.