P 1020 automatic polarimeter

NMR spectra were recorded in Bruker ARX 500 spectrometer (Bruker BioSpin Group, Zurich, Switzerland) operating at 500/125 MHz, in ppm relative to Me₄Si as internal reference; J in Hz. UV spectra were measured on a Shimadzu UV-2600 spectrophotometer (Tokyo, Japan) in nm(λmax). IR spectra were recorded on a Bruker Tensor-27 FT-IR spectrophotometer (Ettlingen, Germany) with KBr cells in cm⁻¹. Optical rotations were obtained on a Jasco P-1020 automatic polarimeter (Tokyo, Japan). HR Q-TOF MS spectra were recorded on an Agillent 6520 mass spectrometer (Agilent Technologies, Santa Clara, CA, USA) in m/z. Circular dichroism (CD)spectra were measured on a Chirascan Plus spectroscope (Applied photophysics, Leatherhead, Surrey, UK). X-ray single diffraction was performed on an Oxford Gemini S Ultra diffractometer (Rigaku, Oxford, UK). Column chromatography was performed with silica gel (Qingdao Marine Chemical Company, Qingdao, China), reverse phase octadecyl-silica (Merck, Darmstadt, Germany), and Sephadex LH20 (Amersham Biosciences, Piscataway, NJ, USA). Thin layer chromatography was performed on the precoated silica gel plates (GF254, Qingdao Marine Chemical Company, Qingdao, China). Organic solvents used were from Sino-pharm Chemical Reagent Co., Ltd. (Shanghai, China).

UV and IR spectra were obtained on a JASCO V-550 spectrophotometer and a JASCO FI/IR-480 Plus Fourier transform infrared spectrometer, respectively. CD spectra were recorded on a Chirascan spectropolarimeter. Optical rotations were determined with a JASCO P-1020 Automatic Polarimeter. HR-ESI-MS data were obtained using an Agilent 6210 ESI/TOF mass spectrometer. NMR experiments were performed on Bruker AV-600 and AV-400 spectrometers. HPLC was carried out on an Agilent 1260 chromatograph and a semi-preparative chromatograph with a DAD detector.
Column chromatography (CC) was performed on silica gel (60–80 mesh, 200–300 mesh, Qingdao Marine Chemical Inc., Qingdao, China), Sephadex LH-20 (Pharmacia Biotech AB), and YMC-Pack ODS (Merck). TLC was carried out on glass precoated silica gel GF₂₅₄ plates. Waters X-bridge C₁₈ column (250 × 4.6 mm, 5 μm; 250 × 10 mm, 5 μm) was used to analyze and isolate the compounds.