Normal phase silica gel

Analytical HPLC was performed on an Agilent 1200 with an Agilent DAD spectrophotometer (Agilent Technologies, Santa Clara, USA) and a YMC-Pack Pro C18 (5 μm, 4.6 × 250 mm, YMC Ltd., Japan). Preparative HPLC was performed on a Shimadzu LC-20A spectrophotometer and a YMC-Pack Pro C18 column (5 μm, 20 × 250 mm). NMR (1D and 2D) spectra were recorded by a Bruker AVANCE III 600 spectrometer. The ESI-MS spectra were measured on a 6430 Triple Quad mass spectrometer (Agilent Technologies, Santa Clara, USA). The HR-ESI-MS spectra were recorded using a Q-TOF mass spectrometer (Waters Corporation, Milford, USA). UV and IR data were measured using a JASCO V-550 UV/vis and a JASCO FT/IR-480 plus spectrometers (Jasco, Japan), respectively. Normal phase silica-gel (200–300 mesh) was purchased from Qingdao Haiyang Chemical Co., Ltd., Octadecylsilanized silica (ODS) gel (50 μm) was purchased from YMC Ltd. in Japan. The optical density was measured on a Tecan Infinite®200 PRO microplate reader (Tecan, Swiss).

The ESI-MS spectra were recorded on a 6430 Triple Quad mass spectrometer (Agilent Technologies, Santa Clara, USA). The HR-ESI-MS spectra were obtained on a Micromass Q-TOF mass spectrometer (Waters Corporation, Milford, USA). 1D and 2D NMR spectra were measured on a Bruker AVANCE III 600 spectrometer. UV data were recorded using a JASCO V-550 UV/vis spectrometer (Jasco International Co., Ltd., Tokyo, Japan). IR data were recorded on a JASCO FT/IR-480 plus spectrometer (Jasco International Co., Ltd., Tokyo, Japan). Optical rotations were measured on a JASCO P1020 digital polarimeter (Jasco International Co., Ltd., Tokyo, Japan). Analytical HPLC was performed on an Agilent 1100 with an Agilent DAD spectrophotometer and a YMC-Pack Pro C18 (5 μm, 4.6 × 250 mm), while preparative HPLC was performed on an Shimadzu LC-20A spectrophotometer and a YMC-Pack Pro C18 column (5 μm, 20 × 250 mm). Normal phase silica gel (200–300 mesh, Qingdao Haiyang Chemical Co., Ltd.) and octadecylsilanized (ODS) silica gel (50 μm, YMC Ltd., Japan) were also used for column chromatography (CC).

The NMR spectra were obtained using a Bruker AV 300 MHz spectrometer (Burker, Fallanden, Switzerland) in CD₃OD and TMS (tetramethylsilane) as the internal standard. High-resolution electrospray ionization mass spectra (HR-ESIMS) were recorded using a UHPLC–Q Exactive Orbitrap–MS (Thermo Fisher Scientific, Boston, MA, USA). Optical rotations were measured with a Rudolph Autopol I automatic polarimeter. Column chromatography was performed using normal-phase silica gel (200–300 mesh, Branch of Qingdao Haiyang Chemical Co., Ltd., Qingdao, China). Thin-layer chromatography (TLC) was conducted on pre-coated silica gel GF₂₅₄ glass plates (200 × 200 mm, Qingdao Haiyang Chemical Co., Ltd., Qingdao, China) and RP-18 F₂₅₄S (Merck KGaA, Darmstadt, Germany). All reagents and solvents were of reagent grade or purified according to standard methods before use.