Uplc it tof mass spectrometer

Optical rotations were measured on an Autopol VI manufactured by Rudolph Research Analytical, Hackettstown, NJ, United States IR spectra were measured on a Nicolet iS10 FT-IR spectrometer (Thermo Fisher Scientific, United States) with KBr disks. NMR spectra were recorded in CDCl₃ (δ_H 7.26 ppm, δ_C 77.16 ppm) or DMSO-d₆ (δ_H 2.50 ppm, δ_C 39.52 ppm) using Bruker Avance III 600 or 800 MHz spectrometers (Bruker Corp, Switzerland). HR-ESI-MS analysis were carried out on a Shimadzu UPLC-IT-TOF mass spectrometer (Shimadzu Corp, Japan). Silica gel (100–200 mesh and 200–300 mesh, Qingdao Marine Chemical Inc, China) and Sephadex LH-20 (18–111 μm, Pharmacia Biotech Ltd, Sweden) were used for the chromatography column (CC). Precoated Silica gel GF₂₅₄ plates (0.20–0.25 mm in thickness, Qingdao Marine Chemical Inc, China) were used for thin-layer chromatography (TLC) analyses. Semipreparative HPLC was conducted on a Hitachi Chromaster system (Hitachi Ltd, Japan), equipped with a DAD detector and a YMC-Triart C₁₈ column (250 × 10.0 mm i. d, 5 μm), using a flow rate of 3.0 ml/min at a column temperature at 28°C, and 0.1% (v/v) acetic acid was added to each HPLC mobile phase.

HRESIMS spectra were obtained with a Shimadzu UPLC-IT-TOF mass spectrometer (Shimadzu Corp: Kyoto, Japan). The UV spectra were measured with a Shimadzu UV-2700 spectrophotometer (Shimadzu Corp: Kyoto, Japan). The IR spectra (KBr) were determined on a Nicolet iS10 spectrometer (Thermo Fisher Scientific: Waltham, MA, USA). Optical rotation was determined in MeOH on an Autopol VI polarimeter (Rudolph Research Analytical: Hackettstown, NJ, USA). The ECD spectra were recorded on a Chirascan circular dichroism spectrometer (Applied Photo Physics Ltd: Surrey, UK). NMR spectra were obtained on a Bruker Avance III 500 (Bruker Corp: Rheinstetten, Germany) with ¹H NMR at 500 MHz and ¹³C NMR at 125 MHz using tetramethylsilane as internal standards. Semi-preparative HPLC was on a Waters 2695 system equipped with a YMC-Pack ODS-A column (250 × 10 mm, 5 μm), using a flow rate of 3.0 mL/min at a column temperature of 28 °C, and detection was performed with a PDA detector. The silica gel GF254 (10~40 μm) for TLC and silica gel (200–300 mesh) for column chromatography (CC) were produced from Qingdao Marine Chemical Factory: Qingdao, China. MCI gel (CHP20P, 75–150 μm) was produced by Mitsubishi Chemical Corp: Kyoto, Japan.