Eca 400 mhz

All solvents and reagents were from Sigma-Aldrich (St. Louis, MO, USA) and used without additional purification. All melting points were determined using Büchi Melting Point M-560 apparatus (Büchi Labortechnik AG, Flawil, Switzerland) and are uncorrected. FTIR spectra were recorded by via Perkin Elmer FTIR Spectrum One (PerkinElmer, Waltham, MA, USA) by using ATR system (4000–650 cm⁻¹). The ¹H and ¹³C NMR spectra were acquired at 298 K using DMSO-d6 as solvent on a JEOL ECA 400 MHz or Bruker Advance 500 MHz spectrometer equipped with a z-gradient, triple-resonance (¹H, ¹³C, ¹⁵N) cryoprobe. An Oxford Instruments Pulsar benchtop NMR 60 MHz Spectrometer (Tubney Woods, Abingdon, Oxford, UK) was used to record the ¹⁹F-NMR spectra. Chemical shifts are expressed in ppm with TMS as an internal reference (TMS, δ = 0 ppm) for protons and trifluoroacetic acid (TFA, δ = −75.39 ppm) for fluorine. Reactions were monitored using TLC on silica gel with ethyl acetate/hexane mixtures as a solvent and compounds visualized via UV lamp. The reported yields are for pure products and have not been optimized.

All chemicals were obtained from suppliers (Sigma-Adrich, St. Louis, MO, USA, TCI, Ark). NMR spectra were recorded on a Bruker ECA-400 MHz (Bruker Co. Billerica, MA, USA) spectrometer with TMS as an internal standard. Chemical shifts were in ppm (δ), and coupling constants (J) were reported in Hertz (Hz). High-resolution electrospray ionization mass spectra (HR-ESI-MS) was performed on the Agilent G6230A TOF LC/MS (Agilent Technologies Co. Ltd., Santa Clara, CA, USA) using ESI ion source. Absorbances in vitro experiments were measured using a spectrophotometer (Thermo, Singapore Republic of Singapore). Column chromatography (CC) was performed using silica gel (Qingdao Marine Chemical Inc., Qingdao, China). Thin-layer chromatography (TLC) was performed with silica gel GF254 (Yantai Huayang New Material Technology Co., Ltd., Yantai, China). Data of in vitro experiments were analyzed and plotted using Graghpad Prism (version 8, GraphPad Software, San Diego, California, 2020).

All solvents and reagents were from Sigma Aldrich and used without further purification. All melting points are uncorrected and were determined on a Büchi Melting Point M-560 apparatus. FTIR spectra were recorded by a Perkin Elmer FTIR Spectrum One by using ATR system (4000–650 cm⁻¹). The ¹H and ¹³C NMR spectra were recorded at 298 K on a JEOL ECA 400 MHz or Bruker Advance 500 MHz spectrometer equipped with a z-gradient, triple-resonance (¹H, ¹³C, ¹⁵N) cryoprobe, using DMSO-d6 as solvent. The ¹⁹F-NMR spectra were acquired on an Oxford Instruments Pulsar benchtop NMR 60 MHz Spectrometer. Chemical shifts are expressed in ppm with tetramethylsilane (TMS, δ = 0 ppm) as an internal reference for protons and trifluoroacetic acid (TFA, δ = − 75.39 ppm) for fluorine. Accurate mass data were obtained using a Waters (Waltham, MA) model LCT Premiere time-of-flight (TOF) mass spectrometer. Reactions were monitored by TLC on silica gel using ethyl acetate/hexane mixtures as a solvent and compounds visualized by UV lamp. The reported yields are for the purified material and are not optimized.