Avance 3 500

Unless otherwise noted, all commercial reagents and solvents were obtained from the commercial provider and used without further purification. Melting points (mp) were obtained with CXM-300 melting point apparatus and are uncorrected. ¹H NMR and ¹³C NMR spectra were recorded on a Bruker Avance 400 (400/101 MHz for ¹H/¹³C) spectrometer or Bruker Avance III 500 (500/126 MHz for ¹H/¹³C) spectrometer (Varian, San Francisco, USA) respectively, in DMSO-d₆ with Me₄Si as the internal standard. ESI high-resolution mass spectra (HRMS) were recorded on an AutospecUitima-TOF spectrometer (Micromass UK Ltd., Manchester, U.K.). Flash chromatography was performed on Combiflash Rf 200 (Teledyne, Nebraska, USA).

Optical rotations were measured on a Perkin-Elmer 341 polarimeter. IR spectra were recorded on a Perkin-Elmer 577 spectrometer with KBr disks. HRESIMS spectra were recorded on a Waters-Micromass Q-TOF Ultima Global electrospray mass spectrometer. NMR spectra were measured on a Bruker Avance III 500 and Varian INOVA 600 spectrometers with the residual CHCl₃(δ_H 7.26 ppm, δ_C 77.0 ppm) as internal standard. Chemical shifts are expressed in δ(ppm) and coupling constants(J) in Hz. ¹H and ¹³C NMR assignments were supported by ¹H-¹H COSY, HSQC, and HMBC experiments. Commercial Silica gel(Qing Dao Hai Yang Chemical Group Co., 200–300 and 400–600 mesh), C18 reversed-phase silica gel(150–200 mesh, Merck) and Sephadex LH-20(Amersham Biosciences) were used for column chromatography. Reversed phase HPLC(Agilent 1100 series liquid chromatography using a VWDG1314A detector at 210 nm and a semi-preparative ODS-HG-5 [5 μm, 10 mm(i.d.) × 25 cm] column was also employed. Pre-coated silica gel GF₂₅₄ plates(Qing Dao Hai Yang Chemical Group Co. Ltd. Qingdao, People’s Republic of China) were used for analytical thin-layer chromatography(TLC). All solvents used were of analytical grade(Shanghai Chemical Reagents Company, Ltd.).