Melting points were measured on a mercury thermometer
apparatus and were uncorrected, whereas optical rotations were
recorded using a JASCO P-1010 polarimeter. The UV spectra and
IR spectra were obtained using a Shimadzu-260 spectrophotometer
and Nicolet 5-SXC spectrophotometer, respectively. NMR
experiments were performed on a Bruker AVANCE II 400 MHz
instrument. Multiplicity determinations (DEPT) and 2D spectra
(COSY, HSQC, HMBC, and NOESY) were obtained using standard
Bruker software. Chemical shifts are given in ppm (d) downfield
from TMS internal standard. HRESIQTOFMS were measured on a
Micro TOFQ II Bruker Daltonics (MA, USA). Single crystal X-ray
measurement was performed on Oxford Diffraction CCD area
detector diffractometer. All H atoms were refined as riding on their
parent atoms, with Uiso(H) values set at 1.2 Ueq or 1.5Ueq of the
parent C atoms. The EtOH solvent molecule was found to show
unresolvable disorder and its contribution to the scattering was
removed with the SQUEEZE option in PLATON (Spek, 2009).
Chromatographic separations were performed by column chromatography
(CC) on silica gel 60 (0.063–0.200 mm) and Sephadex
LH-20 (Sigma–Aldrich), radial chromatography was carried out
employing a radial Chromatotron Model 7924 T on silica gel 60
PF254 Merck (1 mm thick), and prep. TLC was performed on silica
gel 60 F254 (0.2 mm thick) plates.