2.2. Purification and Characterization

The CH and DHC purifications were performed by flash chromatography on a flash-prep PuriFlash^® 4100 LC system from Interchim (Montluçon, France) with prepacked silica columns (30 µm, Interchim PF-Si30-HP) and dual-wavelength collection (λ = 254 and 280 nm). Mixtures of cyclohexane and ethyl acetate were used as eluant.

The CHs and DHCs characterizations were realized by NMR and mass spectrometry. ¹H-NMR spectra were recorded on a Brucker Fourier 300 (300 MHz) (Billerica, MA, USA). Residual Acetone-d₆ and DMSO-d₆ protons signals at δ 2.05 and 2.5 ppm, respectively, were used for the calibration. Data are reported as follows: chemical shift (δ ppm), multiplicity (s = singlet, d = doublet, t = triplet, dd = doublet of doublets, and m = multiplet), coupling constant (Hz), integration and assignment. ¹³C-NMR spectra were recorded on a Bruker Fourier 300 (75 MHz) (Billerica, MA, USA). Residual Acetone-d₆ and DMSO-d₆ protons signals at δ 29.84 ppm and 39.52 ppm, respectively, were used for the calibration. Data are reported as follows: chemical shift (δ ppm), assignment. All NMR assignments were made using COSY, HMBC and HSQC spectra. 1D and 2D NMR spectra (¹H, ¹³C, HSQC, HMBC, and COSY) were recorded using standard Bruker pulse programs.

High-resolution mass spectrometry was performed on an Agilent, 1290 system, equipped with a PDA UV detector and a 6545 Q-TOF mass spectrometer (Wilmington, DE, USA). The source was equipped with a JetStream ESI probe operating at atmospheric pressure. The electrospray interface operated with the following parameters: scanning range of 50–1000, nebulizer 35 psi, gas temperature 325 °C, gas flow 8 L/min, sheath da temperature 350 °C, sheath gas flow 11 L/min. Elution was performed using a Zorbax Eclipse plus C18 (1.8 μm, 50 × 2.1 mm²; Agilent), with the following mobile phases: 0.1% formic acid in water (solvent A) and acetonitrile (solvent B). The flow rate was set at 0.4 mL/min and according to the gradient 0−3 min at 5% of B, 3−4 min from 5% to 10% B, 4−13 min from 10% to 99% B, 13−16 min at 99% B, 16−18 min from 99% to 5% B. The column was heated at 40 °C and the sample injection volume was 1 μL.

FTIR spectra were recorded on a Cary 630 FTIR Spectrometer by Agilent (Wilmington, DE, USA).

Melting points were recorded on a Mettler Toledo MP50 Melting Point System (Greifensee, Switzerland) (heating at 3 °C/min).