Am500 ft nmr spectrometer

Optical rotations were determined on a JASCO P-2000 polarimeter (Hachioji, Tokyo, Japan). High-resolution ESIMS was measured on a Varian 910 spectrometer (Varian, California, USA). IR spectra were obtained on a Bruker 23 TENSOR 37 FT-IR spectrometer (Bruker, Billerica, MA, USA). UV spectra were measured using a UV-1601 spectrometer. The ¹H and ¹³C, HMQC, HMBC, NOESY/ROESY, and COSY NMR spectra were recorded on a Bruker AM500 FTNMR spectrometer (Bruker, Billerica, MA, USA), and tetramethylsilane (TMS) was used as an internal standard. Column chromatography (CC) was performed using a silica gel (Kieselgel 60, 70–230 mesh and 230–400 mesh, Merck, Darmstadt, Germany) or Sephadex™ LH-20 (Supelco, Bellefonte, PA, USA). Thin-layer chromatography (TLC) used precoated silica gel 60 F254 (1.05554.0001, Merck, Darmstadt, Germany), and compounds were visualized by spraying with aqueous 10% H₂SO₄ and heating for 1.5–2 min.

Optical rotation values were recorded on a JASCO P-2000 digital polarimeter (JASCO, Tokyo, Japan). The IR spectra were obtained from a Tensor 37 FT-IR spectrometer (Bruker, Ettlingen, Germany). CD spectra were obtained with a JASCO J-1100 spectropolarimeter. NMR experiments were carried out on a Bruker AM500 FT-NMR spectrometer (Bruker, Rheinstetten, Germany) using residual solvent peak as a reference or tetramethylsilane (TMS) as internal standard. The HR-ESI-MS were recorded on a Waters Q-TOF micromass spectrometer Waters Q-TOF micromass spectrometer and an LTQ Orbitrap XL™ Mass spectrometer. Absorbance of bioassay solutions was read on an xMark microplate spectrophotometer.

1D and 2D NMR experiments (¹H, ¹³C, HSQC, and HMBC) were recorded on a Bruker AM500 FTNMR spectrometer: 500 MHz (¹H NMR), 125 MHz (¹³C NMR). The electrospray ionization (ESI) mass spectra were recorded on an AGILENT 1200 LC-MSD trap spectrometer. Column chromatography (CC) was performed using silica gel (0.040–0.063 mm, Merck) and RP-18 resins (30–50 μm, Fuji Silysia Chemical Ltd.). Thin layer chromatography (TLC) was performed on DC-Alufolien 60 F₂₅₄ (1.05715, Merck) and RP18 F_254s (Merck) plates.

Optical rotations were determined on a JASCO P-2000 polarimeter. The UV spectrum was recorded on a JASCO V-630 spectrophotometer. IR spectra were obtained on a Bruker TENSOR 37 FT-IR spectrometer. The ¹H NMR (500 MHz) and ¹³C NMR (125 MHz) spectra were recorded on a Bruker AM500 FT-NMR spectrometer and TMS was used as an internal standard. Column chromatography (CC) was performed on silica gel (Kieselgel 60, 70–230 mesh and 230–400 mesh, Merck), porous polymer gel (Mitsubishi Chemical, Diaion HP-20, 70 × 180 mm), octadecyl silica (ODS, Cosmosil 140 C₁₈-OPN, Nacalai Tesque), and YMC RP-18 resins (30–50 μm, Fuji Silysia Chemical). Thin layer chromatography (TLC) used pre-coated silica gel 60 F₂₅₄ (1.05554.0001, Merck) and RP-18 F_254S plates (1.15685.0001, Merck) and compounds were visualized by spraying with aqueous 10% H₂SO₄ and heating for 3–5 minutes.

All reagents and solvents were reagent grade or purified according to standard methods before use. Analytical thin-layer chromatography (TLC) was performed with silica gel plates using silica gel 60 GF₂₅₄ (Qingdao Haiyang Chemical Co., Ltd., Qingdao, China). Melting points were measured on an Electrothermal digital apparatus (Beijing, China) and were uncorrected. The ¹H-NMR (500 MHz), and ¹³C−NMR (125 MHz) were obtained on an AM-500 FT-NMR spectrometer (Bruker Corporation, Switzerland) with CDCl₃ as the solvent and TMS as the internal standard. MS were recorded under ESI conditions using a LCQ Fleet instrument (Thermo Fisher, Waltham, MA, USA). Optical rotation was measured by an Autopol II polarimeter (Rudolph, Hackettstown, NJ, USA). Yields were not optimized. The title compounds were synthesized under a nitrogen atmosphere.

NMR spectra were performed on a Bruker AM500 FT-NMR spectrometer (500 MHz for ¹H NMR and 125 MHz for ¹³C NMR). The ESI-HRMS data were generated with a Bruker MicroTOF-QII spectrometer (Bremen, Germany). Open-column chromatography was performed on silica gel 40–63 µm phase (Merck, Darmstadt, Germany) and reversed-phase C₁₈ (Merck, Darmstadt, Germany). TLC analyses were carried out on precoated silica gel 60 F₂₅₄ (Merck, Darmstadt, Germany), and spots were visualized by spraying the plates with 10% H₂SO₄ solution followed by heating.