Optical
rotations were obtained using a Jasco P-2000 polarimeter at 589 nm
using a 1 mL quartz cell (10 cm path length) for solutions in MeOH.
IR data were recorded using a Shimadzu Prestige-21 FTIR spectrophotometer
(ATR). NMR spectra were recorded at ambient probe temperature using
a Bruker Avance 400 MHz Kryo spectrometer. All NMR spectra were acquired
in CDCl3 and referenced to solvent signals at δH 7.26 and δC 77.16. HRESIMS data were acquired
using an Agilent Q-TOF 6540 UHD mass spectrometer (sodium formate).
Preparative HPLC purification was performed at room temperature with
an Agilent 1100 series preparative HPLC system; binary pump system;
column: Kromasil RP C18, particle size 7 μm, dimensions 250
× 25 mm; mobile phase: MeOH or ACN and water; flow rate 20 mL/min;
diode-array UV detector; and 226 fraction collector. Thin-layer chromatography
was performed using Merck silica gel 60 F254 pre-coated
plates (0.25 mm) and visualized by UV fluorescence quenching and staining
with vanillin–H2SO4. Column chromatography
was performed on Merck 60 silica gel (0.063–0.200 mm) or Merck
60 flash silica gel (0.040–0.063 mm) stationary phases.
rotations were obtained using a Jasco P-2000 polarimeter at 589 nm
using a 1 mL quartz cell (10 cm path length) for solutions in MeOH.
IR data were recorded using a Shimadzu Prestige-21 FTIR spectrophotometer
(ATR). NMR spectra were recorded at ambient probe temperature using
a Bruker Avance 400 MHz Kryo spectrometer. All NMR spectra were acquired
in CDCl3 and referenced to solvent signals at δH 7.26 and δC 77.16. HRESIMS data were acquired
using an Agilent Q-TOF 6540 UHD mass spectrometer (sodium formate).
Preparative HPLC purification was performed at room temperature with
an Agilent 1100 series preparative HPLC system; binary pump system;
column: Kromasil RP C18, particle size 7 μm, dimensions 250
× 25 mm; mobile phase: MeOH or ACN and water; flow rate 20 mL/min;
diode-array UV detector; and 226 fraction collector. Thin-layer chromatography
was performed using Merck silica gel 60 F254 pre-coated
plates (0.25 mm) and visualized by UV fluorescence quenching and staining
with vanillin–H2SO4. Column chromatography
was performed on Merck 60 silica gel (0.063–0.200 mm) or Merck
60 flash silica gel (0.040–0.063 mm) stationary phases.