Chiral Stationary Phase Preparation

The appropriate levan derivative was dissolved in dichloromethane. The solution was added to depolarized silica gel (3.00 g), and the mixture was sonicated for a few minutes. The solvent was removed with a rotary evaporator. The resulting chiral stationary phase was suspended in 2-propanol and passed through a sieve. The suspension was then filtered, and the separated chiral stationary phase was dried overnight in an electric dryer. After drying, the stationary phase was packed into the stainless-steel column (250 mm × 4.6 mm I.D.), using a conventional high-pressure slurry packing technique with a Knauer pneumatic HPLC pump (Knauer GmbH, Berlin, Germany).