Avance drx 250

Melting points were determined on an electrothermal apparatus (Büchi 535, Switzerland) in an open capillary tube and are not corrected. The IR spectra 400–4000 cm⁻¹ were recorded on an FT-IR Nicolet iS10 spectrophotometer (Thermo Scientific, USA). The ¹H NMR spectra were measured on a Bruker Avance DRX 250 (250 MHz) spectrometer (Germany). ¹H NMR spectra were measured for approximately 0.03 mol/L while using CDCl₃ and D₂O as solvents and chemical shifts, and were expressed as δ values in ppm against TMS as an internal standard. All names were generated by using structure-to-name and name-to-structure algorithms included with ChemBioDraw Ultra 11.0 (CambridgeSoft). Antioxidant assays were carried out using a Shimadzu UV-1203 spectrophotometer (Japan).

¹H NMR experiments were performed at 298–300 K on Bruker Avance DRX 250 MHz spectrometer equipped with 5 mm SB dual probe with z-gradient, operating at 250.13 MHz for ¹H and/or on a Bruker Avance III 700 spectrometer operating at 700.05 MHz using a Prodigy TCI H&F-C/N-D, z-gradient probe head. Spectra were recorded in DMF-d₇ using the solvent residual peaks as the ¹H internal reference: 2.75, 2.93 and 8.03 ppm. The sample concentrations ranged from 10 to 20 mM (Table 2). Spectra evaluation was completed within TopSpin 3.5 software.