Chirascan ecd spectrometer

Optical rotation was measured on a Rudolph Research Analytical Autopol IV automatic polarimeter (MeOH, c in g/100 mL). The ECD spectrum was recorded in MeOH using an Applied Photophysics Chirascan ECD spectrometer. UV spectra were recorded using a Thermo Scientific Evolution 260 Bio spectrophotometer (Shanghai, China, designed in the USA). IR spectra were obtained on a Thermo Scientific Nicolet iS5 FT-IR spectrophotometer (Madison, WI, USA). NMR spectra were recorded on a Bruker Avance III NMR spectrometer with a CryoProbe (Germany). The proton (¹H) and carbon (¹³C) frequencies are 600.2 and 150.9 MHz, respectively. Chemical shifts (δ) in ppm were referenced using the corresponding solvent signals: δ_H at 2.05 and δ_C at 29.92 for acetone-d₆. Off-line FID processing was conducted with the Bruker TopSpin 3.2 software. HRESIMS data were obtained using a Waters SYNAPT (Milford, MA, USA) mass spectrometer. Silica gel 60, particle size 0.035−0.070 mm, supplied by Fluka, Switzerland (220−440 mesh), and silica gel, 230−400 mesh (Sorbent Technologies, GA, USA) were used for column chromatography. Analytical TLC analysis was carried out on silica gel plates (250 μm, 250 μM with UV254, Sorbent Technologies). Sephadex LH-20–100 was purchased from Sigma Chemical Company, USA. All procedures were carried out at room temperature using organic solvents of analytical grade (Sigma, USA).