G6520 q tof

All reagents and solvents were purchased from commercial sources (J&K Scientific Co., Ltd., Beijing, China; TCI Development Co., Ltd., Shanghai, China; Adamas Reagent, Co., Ltd., Shanghai, China.) and used without further purification. The analytical thin layer chromatography (TLC) was HSGF 254 (0.15–0.2 mm thickness). All products were characterized by their NMR and MS spectra. ¹H and ¹³C nuclear magnetic resonance spectra (NMR) were acquired on a Bruker 400 MHz or 500 MHz or 600 MHz NMR spectrometer (Billerica, MA, USA). Chemical shifts were reported in parts per million (ppm, δ) downfield from tetramethylsilane, and the coupling constants (J) were indicated in Hz. Proton coupling patterns are described as singlet (s), doublet (d), triplet (t), quartet (q), multiplet (m), doublet of doublets (dd), and broad (br). Low-resolution mass spectra (LRMS) data were measured on Agilent 1260 Infinity II (Palo Alto, CA, USA) with Electrospray Ionization (ESI). High-resolution mass spectra (HRMS) data were measured on an Agilent G6520 Q-TOF (Palo Alto, CA, USA) with Electrospray Ionization (ESI). AgOPiv was prepared according to the reported literature method [49 (link)].

For ¹H and ¹³C NMR spectra Bruker Avance III 400 MHz spectrometer was used. The coupling constant was displayed as hertz and the peak multiplicities as s (singlet), d (doublet), dd (doublet of doublet), t (triplet), m (multiplet), br d (broad doublet), br s (broad singlet) and td (triplet of doublet) in the NMR. HPLC used to analyze the purity of chemicals was Agilent 1100 LC/G1956A (column: Agilent Eclipse Plus C18 3.5 μm, 4.6 × 150 mm); Agilent 1100 LC/G1956A (column: Waters Xbridge^®C18 3.5 μm, 4.6 × 150 mm); Agilent 1200/G6410B (column: Eclipse Plus C18 3.5 μm 4.6 × 150 mm); SHIMADZU LC 20AB (column: Xbridge^®C18 3.5 μm 4.6 × 150 mm). In some cases, prep-HPLC (column: Phenomenex Luna C18 150 × 25 mm × 10 μm; mobile phase: [water (0.225% FA)-CAN]; B%: 23–53%, 10 min) was used to purify chemicals. LC/MS was measured using SHIMADZU LCMS-2020 (column: kinetex EVO C18 2.1 × 30 mm, 5 μm), Agilent 1200/G6110A (column: ACE Excel 5 C18 2.1 × 30 mm, 5 μm). High-resolution mass spectra (HRMS) were measured by electrospray ionization (ESI) with an Agilent G6520 Q-TOF.

Nuclear magnetic resonance (NMR) spectra were recorded at room temperature on Bruker Avance III 400 Spectrometer (400 MHz) and Bruker Avance III 500 (Cryo) Spectrometer (500 MHz), using TMS as an internal standard. Chemical shifts are given in ppm and coupling constants in Hz. The following abbreviations were used for ¹H NMR spectra to indicate the signal multiplicities: s (singlet), d (doublet), t (triplet), q (quartet), and m (multiplet). High-resolution mass spectrometry was recorded on the Agilent G6520 Q-TOF. Chemicals were purchased from commercial suppliers. Unless stated otherwise, all the substrates and solvents were purified and dried according to standard methods prior to use.