Ascend 600 spectrometer

The 1D and 2D NMR spectra were recorded using an ASCEND 600 spectrometer (Bruker BioSpin Gmbh, Rheinstetten, Germany) at 298 K. All chemical shifts are reported in ppm from tetramethylsilane, using solvent resonances resulting from incomplete deuteration as the internal reference. The HR-ESIMS data were obtained using a TripleTOF 5600+ system (SCIEX, Framingham, MA, USA). Specific optical rotations were measured using an Autopol III S2 Polarimeter (Rudolph Research Analytical, Hackettstown, NJ, USA). IR spectra were recorded using an FT/IR-4100 spectrometer (JASCO Inc., Easton, MD, USA), while the UV–visible spectra were measured using a Shimadzu UV-1650PC spectrophotometer. Semi-preparative HPLC was performed using a Waters^TM 1525 binary pump and a UV/Visible 2489 detector (Tepnel Pharma Services Limited, Livingston, Scotland). HPLC was performed using a YMC-Pack Pro C-18 column (250 × 10 mm l.D., S-5 µm, 12 nm). Silica gel (0.04–0.063 mm particle size, Merck) and RP-18 (0.04–0.063 mm particle size, Merck) were used for carrying out flash column chromatography. Thin layer chromatography (TLC) was performed using Merck Silica gel 60 F₂₅₄ and RP-18 F₂₅₄ plates. All reagents were purchased from Sigma-Aldrich (Merck KGaA, Darmstadt, Germany).

Melting points are uncorrected. NMR spectra were recorded using a Bruker Ascend 600 spectrometer (Bruker, Billerica, MS, USA). To assign the structures, the following 2D experiments were employed: ¹H-¹³C gradient selected HSQC (Heteronuclear Single Quantum Coherence) and HMBC (Heteronuclear Multiple Bond Coherence) sequences. Standard experimental conditions and standard Bruker program were used. The ¹H- and ¹³C-NMR spectral data are given relative to the TMS signal at 0.0 ppm. EI MS spectra were recorded using an LKB GC MS 20091 spectrometer at 75 eV (LKB, Bromma, Sweden).

Melting points are uncorrected. NMR spectra were recorded using a Bruker Ascend 600 spectrometer (Bruker, Billerica, MA, USA). The following 2D experiments were employed to assign the structures: ¹H-¹³C gradient selected HSQC and HMBC sequences. Standard experimental conditions and standard Bruker programs were used. The ¹H-NMR and ¹³C-NMR spectral data are provided relative to the TMS signal at 0.0 ppm. HR mass spectra were recorded with the Bruker Impact II (Bruker, Billerica, MA, USA).

NMR spectra data were recorded on a Bruker ascend 600 spectrometer (Bruker, Karlsruhe, Germany) with TMS used as a reference. Optical rotations were measured on PerkinElmer Model 341 polarimeter (PerkinElmer, Waltham, MA, USA). UV spectrum data were acquired using HACH DR6000 UV-visible spectrophotometer (Hach, Loveland, CO, USA). IR spectra were recorded as KBr disks on PerkinElmer Spectrum 100 Series FT-IR spectrometers (PerkinElmer, Waltham, MA, USA). HRESIMS data were obtained on a LTQ Orbitrap XL™ Hybrid Ion Trap-Orbitrap FT-MS spectrometer (Thermo, Waltham, MA, USA). TLC was carried out on silica gel GF₂₅₄ plates (Yantai Institute of Chemical industry, Yantai, China) and spots were visualized by UV light (254 and/or 365 nm) and spraying with 10% H₂SO₄ followed by heating. Column chromatography was carried out using silica gel (Qingdao Haiyang Chemical Co., Ltd., Qingdao, China), MCI gel (CHP-20P, 75–150 μm, Mitsubishi Chemical Corporation, Tokyo, Japan), ODS (35–70 μm, Grace, Maryland, MD, USA), and Sephadex LH-20 (GE Healthcare Bio-Science AB, Uppsala, Sweden) as packing materials. Semi-preparative HPLC was performed on a Shimadzu instrument (Shimadzu, Tokyo, Japan) coupled to CBM-20A system controller, LC-20AP pump, SPD-M20A Photodiode Array Detector and SIL-10AP autosampler and equipped with a Shimadzu PRC-ODS column (250 mm × 20 mm i.d., 15 μm).