Autopol 3 polarimeter

Specific optical rotations were collected on a Rudolph Research Analytical (Autopol III) polarimeter (Rudolph Research Analytical, Hackettstown, NJ, USA). IR spectra were measured on a JASCO FT/IR-4100 spectrophotometer (JASCO Corporation, Tokyo, Japan). The 1D and 2D NMR spectra were taken in CDCl₃ using a Bruker 600 MHz spectrometer (Bruker BioSpin GmbH, Rheinstetten, Germany) at 297.1 K. ¹H NMR spectra were collected after 64–128 scans, and ¹³C NMR spectra were collected at a range of 10,000–15,000 scans depending on the sample concentrations. The mixing time for NOESY experiments was set as 0.3 s. Chemical shifts were reported in parts per million relative to CHCl₃ residue (δ_H 7.26, δ_C 77.1) in CDCl₃. High resolution mass-spectra were obtained on a Sciex X500R Q-TOF spectrometer (Framingham, MA, USA) equipped with an ESI source. MPLC was performed using the TELEDYNE ISCO CombiFlash Companion with the TELEDYNE ISCO RediSep Normal-phase Silica Flash Column (Teledyne ISCO, Lincoln, NE, USA). HPLC was performed on a PrimeLine Binary pump (Analytical Scientific Instruments, Inc., El Sobrante, CA, USA) utilizing silica columns (YMC-Pack Silica, 250 × 10 mm I.D., or 250 × 4.6 mm I.D., 5 µm; YMC Co. Ltd., Kyoto, Japan), the Shodex RI-101 (Shoko Scientific Co. Ltd., Yokohama, Japan), or the UV-M201.

Optical rotations were measured with a Rudolph Autopol III polarimeter (Rudolph Research Analytical, Hackettstown, NJ, USA). Shimadzu UV-2550 spectrometer (Beckman, Brea, CA, USA) was used for scanning UV spectroscopy. IR spectra were obtained on a Tensor 27 spectrometer, as KBr pellets (Thermo, Pittsburgh, PA, USA). NMR spectra were recorded on an AV-500 spectrometer (Bruker, Bremen, Germany) with TMS (Tetramethylsilane) as an internal standard. HR-ESI-MS were performed on an API QSTAR Pulsar mass spectrometer (Billerica, MA, USA). Silica gel (200–300 mesh, Qingdao Marine Chemical Inc., Qingdao, China), RP-18 (40–70 mm, Fuji Silysia Chemical Ltd., Kasugai Aichi, Japan) and Sephadex LH-20 (GE Healthcare, Uppsala, Sweden) were used for column chromatography (CC). Semipreparative HPLC (Agilent 1100, Agilent Technologies Inc., Santa Clara, CA, USA) was performed on an Agilent 1100 liquid chromatograph with a Zorbax SB-C₁₈, 9.4 mm × 25 cm, column. Fractions were monitored by TLC and spots were visualized by heating after spraying with 5% H₂SO₄ in ethanol.

Reagents were purchased from Fisher Scientific (Waltham, MA, USA) unless otherwise noted. Optical rotations were measured on a Rudolph Research Analytical Autopol III polarimeter (Hackettstown, NJ, USA). IR spectra were obtained using a JASCO 4100 FT-IR spectrophotometer (Oklahoma City, OK, USA). High resolution mass analyses were performed using an Agilent 6230 TOF LC/MS mass spectrometer (Santa Clara, CA, USA) with a dual ESI and APCI source. Standard 1D and 2D NMR spectra were recorded on a Bruker 400 MHz spectrometer (Billerica, MA, USA). Proton and carbon chemical shifts are reported in ppm and referenced with the ¹H and ¹³C signals of solvents. TLC separations were performed using Whatman silica gel 60 F₂₅₄ aluminum backed TLC plates. HPLC separations were performed with an Agilent 1200 instrument (Santa Clara, CA, USA) with a PDA detector system.