Ecz 500 spectrometer

High-resolution mass spectra (HRESI-TOFMS) were acquired using a Waters Xevo Q-TOF direct probe/MS system utilizing ESI+ mode with a microchannel plate MCP detector (Milford, MA, USA), and optical rotations were determined using an ATAGO AP-300 automated polarimeter (Saitama, Japan). Additionally, the One Perkin Elmer infrared-100 (Shelton, CT, USA) was used to measure the IR spectra. On a JEOL ECZ-500 spectrometer (Tokyo, Japan), the NMR data were collected for ¹H (500 MHz) and ¹³C (125 MHz) using TMS as an internal standard. Then, chromatographic separations were carried out using octadecyl silane (Fuji Sylisia Chemical LTD., Chromatorex C18 DM1020 M, 200–400 mesh) and silica gel G60 (Merck, Darmstadt, Germany, 70–230 and 230–400 mesh). Precoating the TLC plates with GF254 (Merck, 0.25 mm) was followed by detection, which was carried out by spraying 10% H₂SO4 in ethanol and then heating.

All commercial reagents and solvents were used without purification. Melting points were determined with a Hund/Wetzlar micromelting point apparatus (Germany), and are uncorrected. ROESY NMR spectra were obtained using a Bruker AVANCE III™ HD 500 MHz and/or a JEOL ECZ500 spectrometer, both operating at 125.7 MHz for ¹³C and 500 MHz for ¹H. The assignment of hydrogen and carbon signals was based on a combination of 1D and 2D NMR experiments (³H, ¹³C-APT, ¹H,¹H COSY, ¹H,¹³C HSQC and ¹H,¹³C HMBC). Proton and carbon NMR spectra were measured in a Bruker AVANCE III™ 400 or 500 MHz with chemical shifts given in parts per million (ppm) (δ relative to residual solvent peak for ¹H and ¹³C). Coupling constants (J) are given in Hz. The HR-MS spectra were performed with LCQ Advantage (ThermoFisher Scientific, Waltham, MA, United States) using ESI mode. Thin-layer chromatography (TLC) was performed on silica gel (Merck, 60 µm). For column chromatography, neutral silica gel 60 µm (Fluka, Buchs, Switzerland) was used. Analytical samples were dried over phosphorus pentoxide at 50°C/0.25 kPa. The purity of final compounds was assessed by HPLC analysis with ELS detection (evaporative light scattering), and all corresponding chromatographs are enclosed in Supplementary Material.