G1956b single quadrupole mass spectrometer

Optical rotations were measured using a Perkin-Elmer model 343 polarimeter (Perkin-Elmer Inc., Waltham, MA, USA). UV and ECD spectra were recorded on an Applied Photophysics Chirascan spectrometer (Applied Photophysics Ltd., Surrey, UK). IR spectra were measured using a Nicolet 5700 FT-IR microscope spectrometer (FT-IR microscope transmission) (Thermo Electron Corp., Madison, WI, USA). NMR spectra were acquired on a AVANCE III HD 600 MHz spectrometers (Bruker Corp., Karlsruhe, Germany) in CDCl₃ with tetramethylsilane as an internal reference. ESIMS data were obtained using an Agilent 1100 LC/MSD with a G1956B single quadrupole mass spectrometer (Agilent Technologies, Ltd., Santa Clara, CA, USA). HRESIMS data were recorded using a Thermo LTQ Orbitrap XL mass spectrometer (Thermo Fisher Scientific, Waltham, MA, USA). Flash chromatography was performed on an Ez Purifier (Suzhou Lisure Science Co., Ltd., Suzhou, China). Column chromatography was carried out using silica gel (Qingdao Marine Chemical Inc, Qingdao, China) and Toyopearl gel HW-40F (Tosoh Co., Tokyo, Japan). HPLC separation was performed with a Shimadzu LC-20AP binary pump (Shimadzu Co., Kyoto, Japan) equipped with an SPD-M20A diode array detector using a Shiseido Capcell C18 MGII preparative (20 mm × 250 mm) or semi-preparative (10 mm × 250 mm) column.