Mcp 500 automatic polarimeter

Optical rotations were measured with an MCP 500 automatic polarimeter (Anton Paar) with MeCN as solvent. UV spectra were recorded on a UV-2600 spectrometer (Shimadzu). IR spectra were measured on an IR Affinity-1 spectrometer (Shimadzu). ¹H, ¹³C NMR, DEPT, and 2D NMR spectra were recorded on the AVANCE III HD 700 (Bruker). Circular dichroism spectra were measured with a Chirascan circular dichroism spectrometer (Applied Photophysics). HRESIMS spectra data were recorded on a MaXis quadrupole-time-of-flight mass spectrometer. Thin layer chromatography (TLC) was performed on plates precoated with silica gel GF₂₅₄ (10–40 μm). Column chromatography (CC) was performed over silica gel (200–300 mesh and 300–400 mesh) (Qingdao Marine Chemical Factory) and octadecylsilyl silica gel (ODS) (50 μm, YMC). High performance liquid chromatography was performed on an Agilent 1260 HPLC equipped with a DAD detector, using an ODS column (YMC-pack ODS-A, 10 × 250 mm, 5 μm), two chiral-phase columns (Daicel chiralpak IA and IC, 4.6 × 250 mm, 5 μm). All solvents used in CC and HPLC were of analytical grade (Tianjin Damao Chemical Plant, Tianjin, China) and chromatographic grade (Oceanpak, Sweden), respectively. Fractions were monitored by TLC and spots were visualized by heating silica gel plates sprayed with 10% H₂SO₄ in EtOH.

NMR spectra were recorded on an AVANCE III HD-700 spectrometer (Bruker, Billerica, MA, USA) with TMS as the internal standard. HR-ESI-MS spectra data were gathered on a MaXis quadrupole time-of-flight mass spectrometer (Bruker Biospin GmbH, Rheinstetten, Germany). Crystallographic data were collected on a Rigaku XtaLAB AFC12 single-crystal diffractometer (Rigaku, Kyoto, Japan) using Cu Kα radiation. Optical rotations were measured with an MCP500 automatic polarimeter (AntonPaar, Graz, Austria) with MeCN as the solvent. UV spectra were recorded on a UV-2600 spectrometer (Shimadzu, Tokyo, Japan). Circular dichroism spectra were measured with a Chirascan circular dichroism spectrometer (Applied Photophysics, Ltd., Surrey, Leatherhead, UK) with the same concentration of UV measurement (Pathlength 10 mm, Applied Photophysics, Ltd., Surrey, Leatherhead, UK). HPLC purification was performed on an Agilent 1260 HPLC equipped with a DAD detector, using an ODS column (YMC-pack ODS-A, 10 × 250 mm, 5 µM, 3 mL/min). Silica gel (200–300 and 300–400 mesh) and Sephadex LH-20 for column chromatography (CC) were purchased from Qingdao Marine Chemical Group Co. (Qingdao, China) and GE Healthcare (Uppsala, Sweden), respectively. All solvents used in CC and HPLC were of analytical grade (Tianjin Damao Chemical Plant, Tianjin, China) and chromatographic grade (MERDA, Beijing, China), respectively.