The first three, pure, single-isomer, 6-O-sulfo a-cyclodextrins, the sodium salts of hexakis(6-O-sulfo)-a-CD (HxS), hexakis(2,3-di-O-methyl-6-O-sulfo)-a-cyclodextrin (HxDMS) and hexakis(2,3-di-O-acetyl-6-O-sulfo)-a-cyclodextrin (HxDAS) have been synthesized, analytically characterized and utilized as chiral resolving agents in capillary electrophoresis. The purity of each synthetic intermediate and of the final product was determined by HPLC-ELSD and indirect UV-detection capillary electrophoresis. The structural identity of each intermediate and final product was verified by 1D and 2D NMR, and mass spectrometry.HxS, HxDMS and HxDAS have been used to separate a series of neutral, basic, ampholytic and acidic enantiomers in pH 2.5 and pH 9.5 aqueous and acidic methanol background electrolytes using capillary electrophoresis. Rapid separations with satisfactory peak resolution values were obtained for most of the analytes, indicating that HxS, HxDAS and HxDMS can serve as chiral resolving agent for a wide range of analytes. The observed separation patterns follow the predictions of the CHArged Resolving agent Migration (CHARM) model. The separation patterns observed with HxS, HxDAS and HxDMS as chiral resolving agent were compared with those of (1) b-cyclodextrin analogues, such as, heptakis(6-O-sulfo)-b-cyclodextrin (HS), heptakis(2,3-di-O-acetyl-6-O-sulfo)-b-cyclodextrin (HDAS) and heptakis(2,3-di-O-methyl-6-O-sulfo)-b-cyclodextrin (HDMS); (2) g-cyclodextrin analogues, such as, octakis(6-O-sulfo)-g-cyclodextrin (OS), octakis(2,3-di-O-acetyl-6-Osulfo)- g-cyclodextrin (ODAS) and octakis(2,3-di-O-methyl-6-O-sulfo)-g-cyclodextrin (ODMS). The effects of the structure of the analytes, and those of the pH and the solvent of the background electrolyte were also studied.

Single-isomer sulfated cyclodextrins (SISCDs) have proven to be reliable, effective, robust means for separation of enantiomers by capillary electrophoresis (CE). SISCD derivatives used as chiral resolving agents in CE can carry the sulfo groups either at the C2, C3 or C6 positions of the glucopyranose subunits which provides varied intermolecular interactions to bring about favorable enantioselectivities. The first single-isomer, sulfated β-CD that carries the sulfo group at the C2 position, the sodium salt of heptakis(2-O-sulfo-3-O-methyl-6-Oacetyl) cyclomaltoheptaose (HAMS) has been synthesized. The purity of each synthetic intermediate and of the final product was determined by HILIC and reversed phase HPLC. The structural identity of each intermediate and the final product was verified by 1D, and 2D NMR, and MALDI-TOF mass spectrometry. HAMS has been used as chiral resolving agent for the CE separation of a set of nonionic, weak base and strong acid enantiomers in pH 2.5 background electrolytes. Rapid separations with satisfactory peak resolution values were obtained for the enantiomers of most of the nonionic and weak base analytes. Typically, low concentrations of HAMS were required to effect good enantiomer resolution. The trends in the effective mobilities and separation selectivities as a function of HAMS concentrations followed the predictions of the ionic strength-corrected charged resolving agent migration model (CHARM model). HAMS showed poor complexation with the anionic strong electrolyte enantiomers for which no peak resolution was observed. The separation patterns observed with HAMS as chiral resolving agent were compared with those of other β-cyclodextrin analogues, including heptakis(2-O-methyl- 3-O-acetyl-6-O-sulfo)-b-cyclodextrin (HMAS), heptakis(2-O-methyl-3,6-di-O-sulfo)-b- cyclodextrin (HMdiSu), heptakis(2,3-di-O-acetyl-6-O-sulfo)-b-cyclodextrin (HDAS) and heptakis(2,3-di-O-methyl-6-O-sulfo)-b-cyclodextrin (HDMS).

The first three, pure, single-isomer, 6-O-sulfo a-cyclodextrins, the sodium salts of hexakis(6-O-sulfo)-a-CD (HxS), hexakis(2,3-di-O-methyl-6-O-sulfo)-a-cyclodextrin (HxDMS) and hexakis(2,3-di-O-acetyl-6-O-sulfo)-a-cyclodextrin (HxDAS) have been synthesized, analytically characterized and utilized as chiral resolving agents in capillary electrophoresis. The purity of each synthetic intermediate and of the final product was determined by HPLC-ELSD and indirect UV-detection capillary electrophoresis. The structural identity of each intermediate and final product was verified by 1D and 2D NMR, and mass spectrometry.HxS, HxDMS and HxDAS have been used to separate a series of neutral, basic, ampholytic and acidic enantiomers in pH 2.5 and pH 9.5 aqueous and acidic methanol background electrolytes using capillary electrophoresis. Rapid separations with satisfactory peak resolution values were obtained for most of the analytes, indicating that HxS, HxDAS and HxDMS can serve as chiral resolving agent for a wide range of analytes. The observed separation patterns follow the predictions of the CHArged Resolving agent Migration (CHARM) model. The separation patterns observed with HxS, HxDAS and HxDMS as chiral resolving agent were compared with those of (1) b-cyclodextrin analogues, such as, heptakis(6-O-sulfo)-b-cyclodextrin (HS), heptakis(2,3-di-O-acetyl-6-O-sulfo)-b-cyclodextrin (HDAS) and heptakis(2,3-di-O-methyl-6-O-sulfo)-b-cyclodextrin (HDMS); (2) g-cyclodextrin analogues, such as, octakis(6-O-sulfo)-g-cyclodextrin (OS), octakis(2,3-di-O-acetyl-6-Osulfo)- g-cyclodextrin (ODAS) and octakis(2,3-di-O-methyl-6-O-sulfo)-g-cyclodextrin (ODMS). The effects of the structure of the analytes, and those of the pH and the solvent of the background electrolyte were also studied.

Two novel, single-isomer, sulfated cyclodextrins, the sodium salts of heptakis(2- O-methyl-3-O-acetyl-6-O-sulfo)cyclomaltoheptaose (HMAS) and heptakis(2-O-methyl- 6-O-sulfo)cyclomaltoheptaose (HMS) were used as chiral resolving agents in both aqueous and non-aqueous electrophoretic separation of a set of pharmaceutically active weak base enantiomers. Enantiomers of twenty one of the twenty four weak bases were baseline resolved in one or more of the background electrolytes (BGE’s) used. An eight-step synthetic method was used to produce, on a large scale, the title compounds in greater than 97% purity. The purity of the synthetic intermediates and the final products were characterized by HPLC-ELSD and indirect UV-detection capillary electrophoresis (CE), respectively. X-ray crystallography, MALDI-TOF mass spectrometry and 1H as well as 13C NMR spectroscopy allowed for unambiguous characterization of the structure of each intermediate and the final product.