Nicolet 6700 fourier transform spectrometer

Unless stated otherwise all solvents were freshly distilled under argon prior to being used. All chemicals and reagents were purchased from commercially available sources and used without further purification. ¹H and ¹³C NMR spectra were recorded on Bruker Avance III spectrometer, at 500 MHz for proton (¹H) and at 126 MHz for carbon (¹³C). Chemical shifts are given in parts per million (ppm) from tetramethylsilane (TMS) as internal standard in CDCl₃. 2D NMR spectra (HSQC) were recorded at 500 MHz. Coupling constants (J) are reported in hertz (Hz). Unless stated otherwise, all spectra were recorded at 25 °C. High-resolution mass spectra (HRMS) were recorded on a FT-ICR APEX II spectrometer (Bruker Daltonics; Bruker Corporation, Billerica, MA, USA) using electrospray ionization in positive ion mode (ESI+). All reactions were monitored by thin-layer chromatography (TLC). Flash and dry-column flash chromatography were carried out using silica gel (10–18 or 18–32 µm, ICN-Woelm). Melting points were obtained at a heating rate of 4 °C/min, and are uncorrected. IR spectra were recorded by using a Thermo Scientific Nicolet 6700 Fourier-transform spectrometer operated in the ATR mode. Structures of all new compounds were determined by methods of 1D, 2D NMR and IR spectroscopy. Structures of the final compounds were additionally confirmed by high-resolution mass spectrometry (HRMS).