NATIVE/DERIVATIZED CYCLOFRUCTAN 6 BOUND TO RESINS VIA “CLICK” CHEMISTRY AS STATIONARY PHASES FOR ACHIRAL/CHIRAL SEPARATIONS

Abstract

Resin bound cyclofructan 6 (CF6) based stationary phases were prepared by immobilizing functionalized 4-azido-β-cyclofructan 6 (or its derivatives) to chloromethyl modified styrene divinylbenzene (MCI GEL CSP50/P10 CMS) via a 1,2,3-triazole linker. The resin bound native CF6 stationary phase (CF6-CMS) appears to have potential in HILIC separations of different types of polar compounds. The isopropyl carbamate derivatized stationary phases (IP-CF6-CMS) can be used as pH stable chiral stationary phases (CSPs) in HPLC. Under the optimum mobile phase conditions, 37 different types of chiral compounds have been separated on the IP-CF6-CMS column. The optimum mobile phase containing acetonitrile/methanol/triethylamine/acetic acid 70/30/0.2/0.5 was utilized as the starting condition for enantiomeric separations on the IP-CF6-CMS column. Lowering the separation temperature also is beneficial for these separations. The selectivity for some analytes on the IP-CF6-CMS column is comparable with that on the silica gel based LARIHC-CF6 column. These results indicated that there is potential for using these less expensive, but stable, resin based cyclofructan columns for HILIC or chiral separations in process chemistry. Finally, using 1-(1-naphthyl)-ethylamine as the model analyte, the column demonstrated excellent stability and reproducibility.

Keywords:

• click chemistry
• cyclofructan
• enantiomeric separation
• HILIC
• HPLC
• MCI GEL resin

ACKNOWLEDGMENT

The authors would like to express thanks to Dr. Zachary S. Breitbach, Jason Xu, and Jonathan Smuts for their invaluable insights and assistance.

Notes

Enantiomeric separations of compounds 1–24 were obtained in the polar organic mode, and enantiomeric separations of compounds 25–37 were obtained in the normal phase mode.

Mobile phase: acetonitrile/methanol/triethylamine/acetic acid 70/30/0.2/0.5, flow rate: 1.0 mL/min, UV detection: 254 nm.

Mobile phase: acetonitrile/methanol/triethylamine/acetic acid 70/30/0.2/0.5, flow rate: 1.0 mL/min, UV detection: 254 nm.

Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/ljlc.