Avance 2 250

Reactions were monitored by thin-layer chromatography (TLC) using silica gel (60 F254) plates, and the compounds were visualized by UV irradiation. Flash column chromatography was performed with silica gel 60 (230–400.13 mesh, 0.040 × 0.063 mm). The melting points were measured with samples in open capillary tubes. The infrared spectra of compounds were recorded with a Nicolet iS10 instrument (Thermo Scientific, Waltham, MA, USA). The ¹H- and ¹³C-NMR spectra were recorded with DPX 250 (¹³C, 62 MHz), Avance II 250 (¹³C, 63 MHz), Avance 400 (¹³C, 101 MHz), or Avance III HD Nanobay 400 (¹³C, 101 MHz) spectrometers (Bruker, Billerica, MA, USA). The chemical shifts are given in ppm from tetramethylsilane as an internal standard. The coupling constants (J) are reported in Hz. High-resolution mass spectra (HRMS) were recorded with a Bruker Maxis 4G instrument Microwave irradiation was carried out in sealed vessels placed in a Initiator or Initiator + system (400 W maximum power, Biotage, Uppsala, Sweden). The temperatures were measured externally by IR. Pressure was measured by a noninvasive sensor integrated in the cavity lid.