Model 241 spectrophotometer

Optical rotations (OR) values of the new compounds were determined using a JASCO-1020 polarimeter. Electronic circular dichroism (ECD) experiments, including Mo₂(AcO)₄ ICD experiments, were carried out on a JASCO J-815 circular dichroism spectrometer. Ultraviolet–visible (UV) data were provided in MeOH by a Perkin-Elmer model 241 spectrophotometer. Infrared radiation (IR) data of the new compounds (using KBr pellets) were measured on a Nicolet NEXUS 470 spectrophotometer. 1D NMR (¹H NMR and ¹³C NMR) and 2D NMR (HSQC, ¹H-¹H COZY, HMBC and NOESY) data were recorded on a Bruker AV-600 spectrometer. HR-ESI-MS spectra were performed with a Thermo Scientific LTQ Orbitrap XL spectrometer. Semi-preparation HPLC, which had the Shimadzu LC-20AT system with a SPD-M20A detector and a Waters RP-18 column, was used for chemical separation. Further chromatographic separation was taken on 200–300 mesh silica gel and 18–110 μm Sephadex LH-20 columns.

ORD data were recorded in CHCl₃ using JASCO P-2000 spectrometer. IR spectra were acquired using KBr pellets on a Nicolet-Nexus-470 spectrometer. ECD and UV spectra were detected using MeOH as the solvent by a JASCO J-715 and a Perkin-Elmer model 241 spectrophotometer, respectively. HRESIMS spectra were recorded on a Bruker apex-ultra 7.0 T spectrometer. NMR data were obtained from a Bruker Avance 400 spectrometer using TMS as the internal standard. HPLC separation was using a C₁₈ HPLC column (Waters, 10 × 250 mm, 5 μm) on the Shimadzu LC-20AT system coupled with a SPD-M20A photodiode array detector.

Optical rotatory dispersions were acquired using a JASCO P-2000 spectrometer. Optical rotations were obtained on an Optical Activity AA-55 series polarimeter. UV data were performed on a Perkin-Elmer model 241 spectrophotometer in MeOH. Electronic circular dichroism spectra were measured using a JASCO J-715 circular dichroism spectrometer. IR spectra were determined using KBr pellets with a Nicolet NEXUS 470 spectrophotometer. Vibrational circular dichroism spectra were taken on a BioTools ChiralIR-2X spectrophotometer. 1D and 2D NMR data (600 MHz for ¹H and 150 MHz for ¹³C) were acquired on Bruker Avance-III 600 MHz NMR spectrometer with TMS as an internal standard. High-resolution mass data were obtained from a Thermo Scientific LTQ Orbitrap XL spectrometer. HPLC analysis and semi-preparation was performed on a Shimadzu LC-20AT system with a SPD-M20A photodiode array detector, using a Waters RP-18 (XBridge OBD, 5 μm, 10 × 250 mm) and a Waters normal phase (Viridis^TM Silica 2-Ethylpyridine, 5 μm, 10 × 250 mm) columns. Column chromatography was performed on Silica gel 200–300 mesh (Qingdao Marine Chemical Factory), and Sephadex LH-20 (18–110 μm, Pharmacia Fine Chemical Co., Ltd., Sweden).