1D and 2D NMR spectra were recorded on Bruker 400 AVANCE spec-
trometer. HRESIMS spectra were obtained using a Bruker MICROTOF
model mass spectrometer. IR data was obtained using Nicolet 6700
FT-IR spectrometer using KBr disks. UV–visible absorption spectra
were taken on UV-2550 UV–vis spectrometer (Shimadzu, Kyoto,
Japan). Optical rotation was detected by Jasco P-1010 Polarimeter. CD
spectra were recorded on Jasco J-815 Circular Dichroism (CD)
spectropolarimeter.