Optical rotation measurements were carried out on a PerkinElmer model 341 polarimeter with a 10 cm length cell at room temperature. IR and UV spectra were recorded on a Bruker tensor 27 FTIR spectrometer and a Hitachi U-3010 spectrophotometer, respectively. ECD spectra were obtained from a Jasco J-715 spectropolarimeter. 1H, 13C, DEPT135, COSY, HSQC, HMBC, and ROESY NMR spectra were collected on an Agilent 600 MHz NMR apparatus. Chemical shifts (δ) are referenced to tetramethylsilane (TMS) at 0.00 ppm and the residual solvent peak of DMSO-d6 at 39.52 ppm, for proton and carbon, respectively. HRESIMS and HRESIMS/MS spectra were determined on a Waters Xevo G2-XS QTOF spectrometer. HPLC-MS spectra were collected using a Waters HPLC system equipped with a Waters Acquity QDa spectrometer and a Waters XBridge C18 column (4.6 × 250 mm, 5 μm). Analytical thin-layer chromatography (TLC) systems were performed on silica gel 60 F254 plates. Column chromatography was performed using silica gel 60 (200–300 mesh; Yantai). Preparative MPLC was carried out on an Interchim Puriflash 450 apparatus. Semipreparative reversed-phased HPLC (RP-HPLC) was carried out using a Waters 1525 pump equipped with a 2998 photodiode array detector and a Waters XBridge C18 column (10 × 250 mm, 5 μm).
Model 341 polarimeter
Manufactured by PerkinElmer
Sourced in United States
The PerkinElmer Model 341 polarimeter is a scientific instrument designed to measure the optical rotation of a sample. It utilizes a monochromatic light source and employs the principle of optical activity to determine the angle of rotation of a sample's plane of polarization.
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Lab products found in correlation
Gemini 400 spectrometer, by Agilent Technologies (4 mentions)
J 715 spectropolarimeter, by Jasco (3 mentions)
Silica gel, by Qingdao Marine Chemical (3 mentions)
Amx 500 instrument, by Bruker (3 mentions)
Avance 3 400 mhz spectrometer, by Bruker (2 mentions)
J 1500 cd spectrophotometer, by Jasco (2 mentions)
Ascend 500 spectrometer, by Bruker (2 mentions)
Uv 8000 spectrophotometer, by Metash (2 mentions)
Sx102a mass spectrometer, by JEOL (2 mentions)
U 3010 spectrophotometer, by Hitachi (1 mentions)
1525 pump, by Waters Corporation (1 mentions)
Xbridge c18 column, by Waters Corporation (1 mentions)
Hplc system, by Waters Corporation (1 mentions)
Xevo g2 xs qtof spectrometer, by Waters Corporation (1 mentions)
Puriflash 450 apparatus, by Interchim (1 mentions)
Nmr spectrometer, by Agilent Technologies (1 mentions)
Spectrum one ftir spectrometer, by PerkinElmer (1 mentions)
Avance 2 600 mhz spectrometer, by Bruker (1 mentions)
Cary 300 uv vis spectrophotometer, by Agilent Technologies (1 mentions)
Combiflash, by Teledyne (1 mentions)
23 protocols using model 341 polarimeter
1
Structural Characterization of Natural Products
2
Chiral Phosphoric Acid-Catalyzed Enantioselective Reactions
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All reactions were carried out in oven-dried glassware with magnetic stirring under ambient conditions. Unless otherwise noted, all reagents, including the chiral phosphoric acid catalysts 4 and 5, were purchased from commercial supplies and used without further purification, and all solvents were dried and purified according to standard methods prior to use. Substrates 1 (ref. 11 (link)) and 2 (ref. 12 (link)) were synthesized according to the literature methods. 1H NMR and 13C NMR spectra were recorded on a Bruker AVANCE III 400 MHz spectrometer instrument at 400 MHz and 100 MHz spectrometer, respectively. The chemical shifts (δ) were quoted in parts per million (ppm) downfield relative to internal standard TMS (0.0 ppm) and referenced to solvent peaks in the NMR solvent (CDCl3 = δ 7.26 ppm; δ 77.00 ppm; d6-DMSO = δ 2.50 ppm; δ 40.00 ppm). Spin multiplicity were reported using the following abbreviations: s = singlet, d = doublet, t = triplet, dd = doublet of doublet, td = triplet of doublet, m = multiplet. Infrared spectra were recorded on an ATR-FTIR spectrometer. ESI-HRMS were recorded on a Water Micromass GCT Premier mass spectrometer. Optical rotations were measured on a PerkinElmer Model 341 polarimeter at 20 °C. Enantiomeric excess (ee) were measured by chiral HPLC analysis.
3
Structural Determination of Compounds 1 and 2
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The chemical structures of 1 and 2 were determined via multidimensional NMR analysis. 1H-NMR, 13C-NMR and 2D spectra were recorded at 500 MHz (1H)/175 MHz (13C), conducting an Ascend 500 spectrometer using a cryogenically cooled triple resonance probe (Bruker Biospin, Rheinstetten, Germany). Samples were dissolved in methanol-d4. Chemical shifts are reported in ppm relative to tetramethylsilane; the solvent was used as the internal standard.
Chiroptical measurements of1 and 2 in MeOH ([α]D) were obtained on a Model 341 polarimeter (PerkinElmer Inc., Waltham, MA, USA) in a 100 × 2 mm cell at 20 °C. Circular dichroism measurements were performed for 2 at 1.0 mM in MeOH (190–400 nm) with the J-1500 CD spectrophotometer (JASCO, Easton, MD, USA).
Chiroptical measurements of
4
Characterization of Organic Compounds
5
Enantioselective Phosphoric Acid-Catalyzed Reaction
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All reactions were carried out in oven-dried glassware with magnetic stirring under ambient conditions. Unless otherwise noted, all reagents, including the chiral phosphoric acid catalysts 4 and 5, were purchased from commercial supplies and used without further purification, and all solvents were dried and purified according to standard methods prior to use. Substrates 1 (ref. 11 (link)) and 2 (ref. 12 (link)) were synthesized according to the literature methods. 1H NMR and 13C NMR spectra were recorded on a Bruker AVANCE III 400 MHz spectrometer instrument at 400 MHz and 100 MHz spectrometer, respectively. The chemical shifts (δ) were quoted in parts per million (ppm) downfield relative to internal standard TMS (0.0 ppm) and referenced to solvent peaks in the NMR solvent (CDCl3 = δ 7.26 ppm; δ 77.00 ppm; D6-DMSO = δ 2.50 ppm; δ 40.00 ppm). Spin multiplicity were reported using the following abbreviations: s = singlet, d = doublet, t = triplet, dd = doublet of doublet, td = triplet of doublet, m = multiplet. Infrared spectra were recorded on an ATR-FTIR spectrometer. ESI-HRMS were recorded on a Water Micromass GCT Premier mass spectrometer. Optical rotations were measured on a PerkinElmer Model 341 polarimeter at 20 °C. Enantiomeric excess (ee) were measured by chiral HPLC analysis.
6
Analytical Characterization of Compounds
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Optical rotations were
measured on a Model 341 Polarimeter (PerkinElmer). Ultraviolet absorption
spectra were recorded on a Cary 300 UV–vis spectrophotometer
(Agilent Technologies). HR-ESI-MS and MS2 fragmentation
spectra were recorded on a SYNAPT UPLC-ESI-qTOF (Waters). NMR spectra
were measured on an AVANCE II 600 MHz spectrometer equipped with a
5 mm QNP cryoprobe (Bruker). MPLC (CombiFlash, Teledyne ISCO) was
carried out on RediSep Rf solid load cartridge (5 g, Teledyne ISCO).
HPLC separations were performed on either a Waters autopurification
system equipped with a SQ Detector 2 quadrupole MS detector or an
Agilent 1200 series HPLC equipped with a binary pump and a diode array
detector using either Synergi Fusion-RP or Kinetex XB-C18 columns
(Phenomenex).
measured on a Model 341 Polarimeter (PerkinElmer). Ultraviolet absorption
spectra were recorded on a Cary 300 UV–vis spectrophotometer
(Agilent Technologies). HR-ESI-MS and MS2 fragmentation
spectra were recorded on a SYNAPT UPLC-ESI-qTOF (Waters). NMR spectra
were measured on an AVANCE II 600 MHz spectrometer equipped with a
5 mm QNP cryoprobe (Bruker). MPLC (CombiFlash, Teledyne ISCO) was
carried out on RediSep Rf solid load cartridge (5 g, Teledyne ISCO).
HPLC separations were performed on either a Waters autopurification
system equipped with a SQ Detector 2 quadrupole MS detector or an
Agilent 1200 series HPLC equipped with a binary pump and a diode array
detector using either Synergi Fusion-RP or Kinetex XB-C18 columns
(Phenomenex).
7
Spectroscopic Characterization of Natural Compounds
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Optical rotations were measured on a Perkin-Elmer model 341 polarimeter with a 1 dm cell. IR spectra were obtained on a Nicolet NEXUS 670 FT-IR spectrometer. NMR spectra were recorded on a Bruker AVANCE Ш-400 spectrometer. Chemical shifts are given as δ (ppm) using TMS as internal standard. HRESIMS were carried out on a Bruker APEX II mass spectrometer. Sephadex LH-20 (GE Healthcare Bio-science AB, Sweden), C18 reversed-phase Silica gel (YMC, ODS-A, AA120S50), Silica gel (200– 300 mesh, Qingdao Marine Chemical factory, Qingdao, China.) were used for column chromatography (CC). TLC using silica GF254 (10– 40 μm) was detected at 254 nm and spots were visualized by spraying with 5% H2SO4 in EtOH (v/v) followed by heating.
8
Analytical Techniques for Natural Product Characterization
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The optical rotations were measured using a PerkinElmer model 341 polarimeter. A Bruker Tensor spectrometer was used for the measurement of the IR spectra. A Shimadzu UV-260 spectrophotometer was used to measure the UV spectra. 1H, 13C, and 2D NMR spectra were recorded on a Bruker AVANCE III-400, a Bruker AVANCE NEO 600, or a Varian Mercury-600BB spectrometer. The HRESIMS data were acquired utilizing a Bruker Daltonics APEX II spectrometer. The ECD curves were obtained on an Olis DSM-1000 spectrometer. The compounds were purified by a macroporous resin HP-20 and a semipreparative HPLC with a reversed-phase C18 (150 × 10 mm, 10 μm) column. Silica gel (200–300 mesh) for column chromatography and Silica gel GF254 (10–40 mm) for TLC were purchased from the Qingdao Marine Chemical Factory, Qingdao, China.
9
Comprehensive Analytical Characterization
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Optical rotation data were recorded on a PerkinElmer model 341 polarimeter with a 10 cm length cell at room temperature. UV and IR (KBr) spectra were obtained on a Hitachi U-3010 spectrophotometer and Jasco FTIR-400 spectrometer, respectively. CD spectra were obtained on a Jasco J-715 spectropolarimeter in MeCN. NMR spectra including 1D and 2D spectra were acquired at room temperature on Bruker AMX-500 instrument. HRESIMS data were obtained on a Waters Q-Tof micro YA019 mass spectrometer. Reversed-phase HPLC was performed on YMC-Pack Pro C18 RS (5 μm) columns with a Waters 1525 separation module equipped with a Waters 2998 photodiode array detector. Purifications by column chromatography were performed on silica gel 60 (200–300 mesh; Yantai, China), Sephadex LH-20 (18–110 μm, Pharmacia Co.), and ODS (50 μm, YMC Co.). Analytical thin-layer chromatography was carried out using HSGF 254 plates and visualized by spraying with anisaldehyde-H2SO4 reagent.
10
Spectroscopic Characterization of Compounds
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