Esquire 4000 spectrometer

NMR spectra were recorded on a Varian 500 spectrometer (Palo Alto, CA, USA) in DMSO-d₆ or in MeOD, at 500 MHz (¹H) and 125.68 MHz (¹³C); chemical shifts are in ppm (δ) with DMSO (δ = 2.50 for ¹H-NMR and 39.50 for ¹³C-NMR) or with MeOD (δ = 3.34 for ¹H-NMR and 47.60 for ¹³C-NMR) as the reference. Coupling constants J are given in Hertz. ¹H and ¹³C-NMR resonances were assigned using a combination of DEPT, COSY, and HSQC spectra. Infrared (IR) spectra were recorded as thin film or Nujol mull on NaCl plates on a Nicolet Avatar FT-IR spectrometer (Thermo Fisher Scientific, Waltham, MA, USA). Melting points are uncorrected. Electrospray (ESI) mass spectra were obtained on a Bruker Daltonics Esquire 4000 spectrometer (Billerica, MA, USA). HRMS were obtained on a Bruker micrOTOF-Q. Fluorimetric assays were run on a Perkin Elmer LS50B spectrofluorimeter (Waltham, MA, USA). Yields refer to spectroscopically (¹H-NMR) homogeneous materials. Commercial reagents and solvents were purchased from Sigma-Aldrich.

Commercially available chemicals were of reagent grade and used as received. Reaction courses and product mixtures were routinely monitored by thin-layer chromatography (TLC) on silica gel pre-coated F₂₅₄ Merck plates. Melting points were determined using a Stuart SMP300 apparatus and uncorrected. Infrared spectra were recorded on a Jasco 4700 spectrophotometer in nujol mulls. Nuclear magnetic resonance spectra were registered on a Varian 400 MHz (400 for ¹H-NMR and 101 MHz for ¹³C-NMR), shown in Supplementary Figure 8. Chemical shifts are reported as δ (ppm) in CDCl₃ solution (δ = 7.26 ppm for ¹H-NMR and δ = 77.2 for ¹³C-NMR) or DMSO-d6 (δ = 2.49 ppm for ¹H-NMR and δ = 39.52 for ¹³C-NMR); 20 µL of D₂O was added to assign NH and OH protons. Microanalyses (C, H, N) were carried out using an Elementar Vario ELIII apparatus and were in agreement with theoretical values ± 0.4%. ESI-MS spectra (LRMS) were recorded on a Bruker Daltonics Esquire 4000 spectrometer by infusion of a solution of the sample in MeOH (HPLC grade). Microwave oven synthesizer Anton Paar monowave 400.

All reagents and solvents were of analytical grade and used as received. Flash chromatography was performed using Silica Gel 60 (70–230 mesh, Merck, Milan, Italy). Reaction courses were monitored on precoated silica gel TLC-GF₂₅₄ plates (Merck) and spots were visualized under ultraviolet light at 254 nm or iodine vapors. Melting points (°C) were determined with a Stuart SMP 300 apparatus in open glass capillaries and were uncorrected. Agilent Cary-60 spectrophotometer UV-Vis was employed to record the spectra and quantify the absorbance. Infrared spectra were recorded on an FTIR Jasco 4700 spectrophotometer in nujol mulls. Nuclear magnetic resonance spectra were obtained on a Varian 400 MHz. Chemical shifts are reported as δ (ppm) in CDCl₃ solution related to tetramethyl silane as an internal standard; 1 drop of D₂O was added to assign NH or OH protons. ¹H-¹H coupling constants (J) are given in Hz and the splitting abbreviations used are s, singlet; d, doublet; dd, doublet of doublets; ddd: doublet of doublet of doublets; t, triplet; tt, triplet of triplets; dt, doublet of triplets; q, quartet; m, multiplet. Microanalyses (C, H, N) were carried out with Elementar Vario ELIII apparatus and were in agreement with theoretical values ±0.4%. ESI-MS spectra were recorded on a Bruker Daltonics Esquire 4000 spectrometer (MeOH ultrapure as solvent).