Jsm gcmateii spectrometer

The melting points were determined on a Krüss KSP 1N capillary melting point apparatus. Infrared (IR) spectra (ATR-FT or KBr) were recorded on a PerkinElmer 2000 spectrophotometer. ¹H and ¹³C nuclear magnetic resonance (NMRs) spectra were captured on a Varian Mercury (300 MHz) instrument, with CDCl₃ as the solvent and tetramethylsilane (TMS) as the internal standard. Signal assignments were based on two-dimensional NMR spectra (heteronuclear multiple quantum correlation [HMQC] and heteronuclear multiple-bond correlation [HMBC]). High-resolution mass spectra (HRMS) were obtained (in electron impact mode) on a Jeol JSM-GCMateII spectrometer. Analytical thin-layer chromatography was carried out using E. Merck silica gel 60 F254-coated 0.25 plates, visualized by using a long- and short-wavelength UV lamp. Flash column chromatography was conducted over Natland International Co. silica gel (230-400 and 230-400 mesh). All air moisture-sensitive reactions were carried out under N₂ using oven-dried glassware. CH₂Cl₂ and DMF (Sigma-Aldrich) were distilled over CaH₂ (Sigma-Aldrich) prior to use. All other reagents (Sigma-Aldrich) were employed without further purification.

The synthesized compounds were purified by flash column chromatography with silica gel (Natland 230–400 mesh). TLC was performed with silica plates and visualized by using a UV lamp at 254 nm or iodine. The aldehydes, malononitrile and phenols were purchased from Sigma-Aldrich (St. Louis, MO, USA). Infrared spectra were recorded on a Perkin Elmer 2000 FT-IR instrument. Melting points were determined with a Fisher-Johns melting point apparatus. High resolution mass spectra (HRMS) were captured with electron ionization (70 eV) on a JEOL JSM-GC Mate II spectrometer. NMR spectra were obtained on Varian Mercury (300 MHz), Varian VNMR System (500 MHz), and Bruker 600 AVANCE III (600 MHz) instruments, utilizing acetone-d₆ and CDCl₃ as solvents. Most of the NMR assignments are based on extensive 2D homo- and hetero-nuclear experiments. The purity of compounds was determined by high performance liquid chromatography (HPLC) with UV-visible detector Agilent Technologies 1260 model with Eclipse XDB-C18 column of 5 µm and 4.6 × 250 mm. All samples were run with a flow of 100% MeCN (1 mL/min).