3.1. General Information

Nuclear magnetic resonance (NMR) spectra were obtained using a Varian 400 spectrometer (Varian, Palo Alto, CA, USA) 400 MHz spectrometer operated at 400 MHz for ¹H-NMR and at 100 MHz for ¹³C-NMR. High-resolution mass spectra data were measured on a Xevo G2 Q-TOF mass spectrometer (Waters, Milford, MA, USA). Fourier Transform Infrared (FT-IR) recorded on a Nicolet™ iS™ 5 FT-IR spectrometer (ThermoFisher Scientific, Madison, WI, USA) were used. Ultraviolet visible spectroscopy was performed using a DU 730 UV/Vis spectrophotometer (Beckman Coulter GmbH, North Rhine-Westphalia, Germany). Optical rotation and CD data are also given in the Supplementary file. Semi-preparative high performance liquid chromatography (HPLC) was performed on a system equipped with a Gilson 321 pump and Gilson 172 Diode Array Detector (Gilson, Madison, WI, USA) using YMC-pack Ph (250 × 20 mm) and YMC-pack Ph (250 × 10 mm) HPLC columns (YMC, Kyoto, Japan). Water was purified using a Milli-Q system (Waters Corporation, Milford, MA, USA). Column chromatography on C-18 RP silica gel (Cosmosil, Kyoto, Japan) and Sephadex LH-20 (GE Healthcare, Uppsala, Sweden) was conducted, and TLC analysis on silica gel 60 F₂₅₄ plates (Merck, Darmstadt, Germany) was done. The spots were visualized by spraying with 10% aqueous H₂SO₄.