Semi preparative hplc

UV spectra were recorded on a Beckman DU 640 spectrophotometer (Beckman Coulter Inc., Brea, CA, USA). Specific rotations were measured with a JASCO P-1020 digital polarimeter (JASCO Corporation, Tokyo, Japan). ESIMS were obtained on a Thermo Scientific LTQ Orbitrap XL mass spectrometer (Thermo Fisher Scientific, Waltham, MA, USA) or a Micromass Q-TOF ULTIMA GLOBAL GAA076 LC Mass spectrometer (Wasters Corporation, Milford, MA, USA). CD spectra were measured on a JASCO J-815 spectropolarimeter (JASCO Corporation, Tokyo, Japan). NMR spectra were recorded with an Agilent 500 MHz DD2 spectrometer (Agilent Technologies Inc., Santa Clara, CA, USA) using TMS as an internal standard, and chemical shifts were recorded as δ-values. Semi-preparative HPLC (Hitachi, Tokyo, Japan) was performed on an ODS column (YMC-Pack ODS-A, 10 mm × 250 mm, 5 μm, 3 mL/min, YMC. Co., Ltd., Tokyo, Japan). Medium-pressure preparation liquid chromatography (MPLC) was performed on a Bona-Agela CHEETAHTM HP100 (Beijing Agela Technologies Co., Ltd., Beijing, China). Column chromatography (CC) was performed with silica gel (200–300 mesh, Qingdao Marine Chemical Inc., Qingdao, China) and Sephadex LH-20 (Amersham Biosciences, San Francisco, CA, USA) [25 (link)].

SGC-II was separated and purified by the PLC silica gel plate (Merck, Darmstadt, Germany) in the dichloromethane-methanol 15:1 solvent system (30 mL dichloromethane, 2 mL methanol). The different fractions separated by PLC were dissolved by methanol, respectively. The precipitates, such as silica gel, were removed by filtration, concentrated by the rotary evaporator, and then re-dissolved by adding methanol. The final separation and purification of PLC-VI were carried out by semi-preparative HPLC (HITACHI, Tokyo, Japan) using water (WAHAHA, Hangzhou, China) and acetonitrile (HPLC) as the flow phase. The proportion of acetonitrile gradually increased from 20% to 100% (Table S1). The column was 250 × 10 nm, 120 A C 18 reversed-phase silica gel column (SIGREEN, Beijing, China). After evaporation and concentration of each HPLC eluent, ten components were obtained by dissolving with methanol (The Halorotetin A retention time: 26 min).