Silica gel 60 f254 0.2 mm 200 200 nm

NMR spectra were recorded with a Bruker-Spectrospin AC 300 spectrometer (Rheinstetten, Germany) operating at 300 MHz for ¹H and 75 MHz for ¹³C. The following abbreviations were used to explain the multiplicities: bs = broad singlet, s = singlet, dd = doublet of doublet, d = doublet, t = triplet, m = multiplet. Elemental analyses were performed on a Perkin Elmer 2400 Series II Elemental CHNS analyzer (Waltham, MA, USA). Electrospray ionization (ESI) mass spectra were collected using a Q-TOF instrument supplied by WATERS (Agilent, Palo Alto, CA, USA). Materials: thin-layer chromatography (TLC): TLC plates (Merck, silica gel 60 F₂₅₄ 0.2 mm 200 × 200 nm) (Darmstadt, Germany); substances were detected using UV light at 254 nm.

The ¹H NMR spectra were recorded at 300 and 400 MHz using a Bruker Avance 300 or Bruker Avance III-400 machine (Rheinstetten, Germany). The chemical shifts were recorded in ppm relative to TMS and with the solvent resonance as the internal standard. Data were reported as follows: chemical shift, multiplicity (bs = broad singlet, s = singlet, d = doublet, t = triplet, m = multiplet), coupling constants (Hz), integration. ¹³C {¹H} NMR data were collected at 75 or 100 MHz with complete proton decoupling with the solvent resonance as the internal standard. Elemental analyses were performed on a Perkin Elmer 2400 Series II Elemental CHNS analyzer (Waltham, MA, USA). Materials: thin-layer chromatography (TLC): TLC plates (Merck, silica gel 60 F254 0.2 mm, 200 × 200 nm) (Darmstadt, Germany); substances were detected using UV light at 254 nm.