Rp 18

Optical rotations were obtained on a PerkinElmer 241 Polarimeter (Waltham, MA, USA), and CD measurements were performed with a JASCO J-815 Spectropolarimeter. UV data were measured using a Beckman Coulter DU 800 spectrometer (Tokyo, Japan). IR spectra were recorded using a Shimadzu FTIR-8400S spectrophotometer (Tokyo, Japan). NMR spectra were acquired with a Bruker 500 (Munich, Germany) instruments operating at 500 (¹H) and 125 (¹³C) MHz using the solvent signals (CD₃OD: δ_H 3.31/δ_C 49.0 ppm) as references. The HRESIMS experiments were carried out on a TOF-ESI-MS (Waters Synapt G2, USA) equipment. HPLC for purifications were performed on a Waters 2489 Semiprep-HPLC System using an ODS column (RP-18, 250 × 10 mm, YMC Pack, 5 μm; detector: UV; Kyoto, Japan). Sephadex LH-20 (Pharmacia Biotech AB, Uppsala, Sweden) and silica gel (80–100, 100–200, and 200–300 mesh; Qingdao Marine Chemical Plant, Qingdao, China) were used for column chromatography, and thin layer chromatography (TLC) was carried out with glass precoated silica gel GF254 (0.20–0.25 mm; Qingdao Marine Chemical Plant, Qingdao, China).

The IR spectra were obtained using an IMPACT 400 (KBr) spectrometer. ¹H NMR (500 MHz), ¹³C NMR (125 MHz), and 2D-NMR spectra were recorded with an INOVA-500 spectrometer with TMS as an internal standard. Values were given in ppm. HRESIMS were obtained using an Agilent 1100 series LC/MSD ion trap mass spectrometer. The optical rotations were measured with a Jasco P-2000 polarimeter. Column chromatography was performed on macroporous resin (Diaion HP-20, Mitsubishi Chemical Corp., Tokyo, Japan), Rp-18 (50 μm, YMC, Kyoto, Japan), and Sephadex LH-20 (Pharmacia Fine Chemicals, Uppsala, Sweden). Preparative HPLC separation was performed using a Shimadzu LC-10AT instrument with an SPD-10A detector using a YMC-Pack ODS-A column (250 mm × 20 mm, 5 μm).

Column chromatography was performed using Kiselgel 60 (Merck, Art. 7734, Art. 9385, NJ, USA) and RP-18 (YMC, Art. 14878, Japan). All purifications were monitored using thin-layer chromatography (TLC) precoated with Kiselgel 60 F₂₅₄ (Merck, Art. 5715). Compound purifications were performed using a high-performance liquid chromatography (HPLC) core system (Thermo Scientific, Germering, Germany; Dionex Ultimate 3000 Diode Array with ELSD at 254, 280, and 365 nm; and a Dionex Ultimate 3000 pump). A Kinetex 5 μm C18 100 Å (250 × 4.6 mm, Phenomenex, CA, USA) column was used for isolation. The mobile phase consisted of solvent A (water with 0.1% acetic acid) and solvent B (MeOH with 0.1% acetic acid) at a flow rate of 1.0 mL/min. The injection volume was 10 μL, and the column temperature was 35 °C. The ¹H-NMR spectrum was recorded using a Bruker Avance Digital 500 spectrometer (Karlsruhe, Germany) at 500 MHz. Chemical shifts were provided as δ (ppm) from tetramethylsilane (TMS). All of the reagents were purchased from Sigma-Aldrich (St. Louis, MO, USA).