Merck silica gel

All chemicals were purchased from commercial sources (Sigma Aldrich (St. Louis, MO, USA), Acros Organics (Geel, Belgium)) and used without further purification. ¹H and ¹³C NMR spectra were recorded on a Bruker AV-300 spectrometer (Bruker Corporation, Billerica, MA, USA) (300.13 MHz and 75.46 MHz, respectively), Bruker AV-400 (Bruker Corporation, Billerica, MA, USA) (400.13 MHz and 100.61 MHz), Bruker DRX-500 (Bruker Corporation, Billerica, MA, USA) (500.13 MHz and 125.76 MHz). Mass spectra (70 eV) were recorded on a DFS Thermo Scientific high-resolution mass spectrometer. A PolAAr 3005 polarimeter (Optical Activity, Ramsey, UK) was used to measure optical rotations [α]_D. Melting points were measured on a Mettler Toledo FP900 Thermosystem apparatus (Mettler Toledo, Cornellà de Llobregat, Spain). Merck silica gel (Merck, Darmstadt, Germany, 63−200 μm) (63−200 μm) was used for column chromatography. Spectral and analytical measurements were carried out at the Multi-Access Chemical Service Center of Siberian Branch of Russian Academy of Sciences (SB RAS).

The analytical and spectral studies were conducted at the Chemical Service Center for the collective use of Siberian Branch of the Russian Academy of Science. The 1H and ¹³C-NMR spectra for solutions of the compounds in CDCl₃ were recorded on a Bruker AV-400 spectrometer (Bruker Corporation, Hanau, Germany; operating frequencies 400.13 MHz for ¹H and 100.61 for ¹³C). The residual signals of the solvent were used as references (δH 7.27, δC 77.1 for CDCl₃). Merck silica gel (63–200 μ) was used for the column chromatography. Thin-layer chromatography was performed on TLC Silica gel 60F₂₅₄ (Merck KGaA, Darmstadt, Germany). The target compounds reported in this manuscript had a purity of at least 95% (HPLC). All chemicals were used as described unless otherwise noted. Reagent-grade solvents were redistilled prior to use. Synthetic starting materials, reagents, and solvents were purchased from Sigma-Aldrich (St. Louis, MO, USA), Acros Organics (Geel, Belgium), and AlfaAesar (Heysham, UK).
(R)-(+)-Usnic acid (+)-9 was purchased from Zhejiang Yixin Pharmaceutical Co., Ltd. (Lanxi, China). Compounds 3,4 were obtained using a known procedure. The spectra of the substances coincided with that in the literature [31 (link),32 (link)].

Melting points were uncorrected and were measured on a Mettler Toledo instrument. IR spectra were recorded on an Alpha FT-IR Spectrometer from Bruker, while 1D and 2D NMR spectra were obtained on a Bruker DRX 500 (500 MHz for ¹H and 125 MHz for ¹³C spectra) spectrometer (Bruker, Rheinstetten, Germany) with chemical shifts reported in δ (ppm) using TMS (δ_H) as an internal standard. The HR-ESI-MS were obtained on LTQ-FT instrument (Thermo Scientific, Waltham, MA). UPLC–MS were measured by a Shimadzu UPLC–MS system using a L⁻ column 2 ODS (I.D. 2.1 × 100 mm, Chemical Evaluation and Research Institute, Tokyo, Japan), at a flow rate of 0.2 mL/min, a detection wavelength of 350 and 300 nm, and FMW (HCOOH/MeCN/H₂O = 1:12:87) as eluent, ESI⁺ 4.5 kV, ESI⁻ 3.5 kV, 250 °C. Optical rotations were measured on a Perkin-Elmer 341 polarimeter. Silica gel 60 (230–400 mesh E. Merck, Darmstadt, Germany) was employed for column chromatography (CC), the solvent mixing systems for elution were mainly CH₂Cl₂–MeOH with increasing polarity. Analytical thin layer chromatography (TLC) was carried out on Merck silica gel (Merck, Darmstadt, Germany) 60 PF₂₅₄ plates (0.25 mm layer thickness).

All spectral data were procured using the following instruments: Fourier-transform Infrared (FTIR) spectra were obtained using a PerkinElmer 2000 FTIR Spectrum spectrometer (PerkinElmer, Waltham, MA, USA). Nuclear magnetic resonance (NMR) spectra were recorded on a Bruker AVN 500 MHz spectrometer (Bruker Bioscience, Billerica, MA, USA). Data were analysed with the Top Spin 3.6.1 software package (Bruker Bioscience, Billerica, MA, USA). Chemical shifts were internally calibrated using the residual CHCl₃ solvent peak in CDCl₃ (¹H, δ 7.26), the CDCl₃ solvent signal (¹³C, δ 77.0) or the tetramethylsilane (TMS) signal (¹H or ¹³C, δ 0.00 ppm). Tetrahydrofuran (THF, QRëC, Grade AR) was freshly distilled from sodium benzophenone ketyl. Dimethylformamide (DMF, QRëC, Grade AR) was dried over 4 Å molecular sieves prior to use. All other commercially available chemicals and materials were used without further purification. Column chromatography was performed using Merck silica gel (0.040–0.063 mm) (Merck & Co., Kenilworth, NJ, USA). Thin Layer Chromatography (TLC) was completed with silica gel-coated aluminium sheets (silica gel 60 F₂₅₄).
The procedure of intermediates and final compounds synthesis and their NMR; ATR-IR and HRMS spectra of the compounds are presented in Supplementary Materials.

All solvents and reagents were purchased from Sigma-Aldrich (Deisenhofen, Germany) and used without further purification. 4-Hydroxyacetophenone was purchased from Acros (Thermo Fisher Scientific Geel–Belgium). The monitoring of reaction was done by the utilization of pre-coated silica gel plates (60 F₂₅₄) and thin layer chromatography (TLC). The normal phase silica gel (Merck, 70–230 mesh) was used to perform column chromatography purification, while the Merck silica gel (230–400 mesh) was utilized to perform the vacuum liquid chromatography.
A controllable single-mode microwave reactor, CEM Discover Microwave™ designed for synthetic utilization, was used. The reactor consists of power and pressure controls in addition to a magnetic stirrer. The temperature is controlled by an IR sensor. Melting points were measured using Sanyo MPD350 apparatus (Gallenkamp, Osaka, Japan) with digital display, and they were not corrected. A Perkin Elmer ATR spectrophotometer (Waltham, MA, USA) was used to record the infrared (IR) spectra. A Bruker Advance 400 MHz spectrometer (Fällanden, Switzerland) was used to record ¹H NMR and ¹³C NMR spectra. NMR samples were separately measured in DMSO, CDCl₃, and MeOD at room temperature. Mass spectra were recorded on Finnigan MAT95XL (ThermoFisher Scientific, Bremen, Germany) using (EI), at 70 eV.