Microsoft time of flight qii mass spectrometer

High-resolution electrospray ionization mass spectra (HR-ESI-MS) were obtained using a Bruker microsoft time-of-flight QII mass spectrometer (Bruker Daltonics, Fremont, CA, USA). The NMR spectra were recorded using Bruker AV 500MHz spectrometer (Bruker, Fällanden, Switzerland). Optical rotation was measured using a Rudolph Autopol I automatic polarimeter (Rudolph Research Analytical, Hackettstown, NJ, USA). Column chromatography was performed using silica gel (200–300 mesh, Branch of Qingdao Haiyang Chemical Co., Ltd., Qingdao, China) and Sephadex LH-20 (Shanghai Yuanye Biological Technology Co., Ltd., Shanghai, China). Lichroprep RP-18 gel (40–60 μm) was purchased from Merck KGaA (Darmstadt, Germany). Thin layer chromatography (TLC) was performed with precoated silica gel GF 254 glass plates (100 × 200 mm, Branch of Qingdao Haiyang Chemical Co., Ltd.). All other chemicals and solvents were analytical grade and used without further purification.

HR-ESI-MS were obtained using a Bruker microsoft time-of-flight QII mass spectrometer (Bruker Daltonics, Fremont, CA, USA). The NMR spectra were recorded using a Bruker AV 600/400 MHz spectrometer (Bruker, Fällanden, Switzerland). Optical rotation was measured using a Rudolph Autopol I automatic polarimeter (Rudolph Research Analytical, Hackettstown, NJ, USA). Column chromatography was performed using silica gel (200–300 mesh) and Sephadex LH-20 (Shanghai Yuanye Biological Technology Co., Ltd., Shanghai, China), and Lichroprep RP-18 gel (40–60 µm) was purchased from Merck KGaA (Darmstadt, Germany). Thin-layer chromatography (TLC) was performed with precoated silica gel GF 254 glass plates (100 mm × 200 mm, Branch of Qingdao Haiyang Chemical Co., Ltd.). All other chemicals and solvents were of analytical grade and used without further purification.