High performance liquid chromatography (HPLC) separation
was performed with a Cosmosil C18 (4.6150 mm) column and
using a Waters 600 controller pump with manual injection. A
Waters 996 photo diode array detector and Millennium 2010
(version 2.15.01) were used. All injections were monitored at
214 nm and fraction collection was done manually. Solvent system:
solvent A = water, 0.1% trifluoroacetic acid (TFA); solvent B =
acetonitrile, 0.1% TFA. Gradient: 75% A, ramp to 5% A over
20 min, and continue for 10 min.