The optical rotation were measured on a JASCO P-2000
polarimeter, and the CD spectra were recorded on a JASCO J-715
spectropolarimeter (Tokyo, Japan). NMR spectra were measured on
a Bruker Ascend III 700 spectrometer (Rheinstetten, Germany)
with tetramethylsilane as an internal standard, and chemical shifts
are expressed in d values. HRESI–MS was obtained on Triple TOF
5600+ mass spectrometer (AB SCIX, USA). Open column chromatography
was performed using Diaion HP-20 (Mitsubishi Chemical,
Japan) and ODS-A (12 nm S-7 mm, YMC GEL, Japan). Thin layer
chromatography using pre-coated silica gel 60 F254 (0.25 mm,
Merck) and pre-coated silica gel 60 RP-18 F254S(0.25 mm, Merck),
and spots were detected by a 10% vanillin-H2SO4 in water spray
reagent. Preparative HPLC was performed on a Shimadzu (LC-8A
pump and SPD-20A UV/VIS detector) and a YMC-Pack ODS A
column (250
20 mmI.D.), using a mixed solvent system of MeCNwater
at a
flow rate of 10 mL/min. MPLC (Combi Flash RF, Teledyne
ISCO, USA) separations were performed on a RediSep1 Rf silica gel
and C18 column. All other chemicals and reagents were analytical
grade.