Structural identification of compound 1 was achieved using mass spectroscopy, 1D and 2D NMR. NMR spectra were recorded on a Bruker High Performance Digital FT-NMR-Spectrophotometer Avance III HD (1H-NMR: 400 MHz, 13C-NMR: 100 MHz, Bremen, Germany). NMR spectra were recorded in CD3OD using TMS as an internal standard. The solvent used was 500 μl, and the number of scans (NS) was 200 automatically locked based on the CD3OD signal at 3.30 ppm. Chemical shift values were recorded in δ ppm.
Mass spectrum was obtained using an XEVO TQD triple quadrupole(Waters Corporation, Milford, MA01757 USA) mass spectrometer. Source temperature 150 °C, cone voltage 30 eV, capillary voltage 3 kV, desolvation temperature 440 °C, cone gas flow 50 L/h, and desolvation gas flow 900 L/h. Mass spectra were detected in the ESI between m/z 100 and 1000. The peaks and spectra were processed using the Maslynx 4.1 software and tentatively identified by comparing their retention times (Rt) and mass spectra with reported data.
Mass spectrum was obtained using an XEVO TQD triple quadrupole(Waters Corporation, Milford, MA01757 USA) mass spectrometer. Source temperature 150 °C, cone voltage 30 eV, capillary voltage 3 kV, desolvation temperature 440 °C, cone gas flow 50 L/h, and desolvation gas flow 900 L/h. Mass spectra were detected in the ESI between m/z 100 and 1000. The peaks and spectra were processed using the Maslynx 4.1 software and tentatively identified by comparing their retention times (Rt) and mass spectra with reported data.