Nicolet is20 instrument

UV was acquired on a UV/EV300 spectrometer (Thermo Scientific, Waltham, MA, USA), and IR spectra were obtained on a Nicolet iS20 instrument (Thermo Fisher Scientific, MA, USA). Optical rotation data were performed by a Jasco P-2000 polarimeter (Jasco, Hachiojishi, Tokyo, Japan). ¹H and ¹³C NMR spectra were acquired on an Agilent 600 MHz spectrometer (Agilent Technologies, Santa Clara, CA, USA), with CDCl₃ (δH 7.26 and δC 77.16) as the solvent and internal standard. HRESIMS data were collected with a Bruker micrOTOF-Q II mass spectrometer (Bruker Daltonik GmbH, Bremen, Germany). A Shimadzu LC-16 series instrument (Shimadzu, Kyoto, Japan) was equipped with C-18 column (5 µm, 10 mm × 250 mm, YMC, Kyoto, Japan) and an SPD-M20A diode array detector (Shimadzu, Kyoto, Japan) for high-performance liquid chromatography (HPLC) analysis. For column chromatography, Silica gel 60 (200–300 mesh; Yantai, China) and octadecylsilyl (ODS) (50 µm, YMC, Kyoto, Japan) were used. A silica gel 60 F254 plate (Merck, Darmstadt, Germany) was used for analytical thin-layer chromatography.

The UV spectrum was obtained using SPD-M20A diode array detector (Shimadzu, Kyoto, Japan). Optical rotation data were tested on an Autopol IV polarimeter (Rudolph, Hackettstown, NJ, USA). The FT-IR spectra were recorded using a Nicolet iS20 instrument (Thermo Fisher Scientific, Waltham, MA, USA), with a resolution of 4 cm⁻¹ and 32 scans in % transmittance mode. A KBr-disk was used for preparing the samples. ¹H and ¹³C NMR spectra were recorded in CDCl₃ containing Me₄Si as internal standard on Agilent 600 MHz spectrometer (Agilent Technologies, Santa Clara, CA, USA). HRESIMS was performed with a Bruker micrOTOF-Q II mass spectrometer (Bruker Daltonik GmbH, Bremen, Germany). HPLC was carried out on a Shimadzu LC-16 series instrument (Shimadzu, Kyoto, Japan), equipped with C-18 column (5 µm, 10 mm × 250 mm, SilGreen, Beijing, China) and an SPD-M20A diode array detector (Shimadzu, Kyoto, Japan). As for column chromatography, silica gel 60 (200–300 mesh; Yantai Jiangyou Silica Gel Development Co. LTD, Yantai, China) and octadecylsilyl (ODS) (50 μm, YMC, Kyoto, Japan) were used.