Ecz 400 mhz spectrometer

For IR spectra, a Nicolet iS5 FT-IR spectrophotometer (Thermo Fisher Scientific, Waltham, MA, USA) was used. Optical rotation values were measured using a Jasco P-1010 digital polarimeter (Jasco, Tokyo, Japan). NMR spectra were measured with a Jeol ECZ 400 MHz spectrometer (Jeol, Tokyo, Japan). ESIMS and HRESIMS analyses were conducted using the Bruker 7 Tesla solariX FTMS system (Bruker, Bremen, Germany). Column chromatography was carried out with silica gel (230–400 mesh, Merck, Darmstadt, Germany). Thin layer chromatography (TLC) was performed on plates precoated with Kieselgel 60 F₂₅₄ (0.25 mm, Merck), then sprayed with 10% H₂SO₄ solution followed by heating to visualize the spots. Normal-phase high performance liquid chromatography (NP-HPLC) was performed using a system comprising a pump (L-7110, Hitachi, Tokyo, Japan), an injection port (Rheodyne 7725i; Rohnert Park, CA, USA) and a semi-preparative normal-phase column (YMC-Pack SIL, 250 × 20 mm, 5 μm; Sigma-Aldrich, St. Louis, MO, USA). Reverse-phase HPLC (RP-HPLC) was performed using a system comprising a Hitachi L-2130 pump, a Hitachi L-2455 photodiode array detector, a Rheodyne 7725i injection port and a semi-preparative reverse-phase column (Luna, 5 μm, C18(2) 100Å, AXIA, 250 × 21.2 mm; Phenomenex, Torrance, CA, USA).