500 ms lc ion trap mass spectrometer

The ¹H and ¹³C NMR spectra were recorded at room temperature on a Bruker Avance II + 300 (UltraShield^™ Magnet) spectrometer operating at 300.130 and 75.468 MHz for proton and carbon-13, respectively. The chemical shifts are reported in ppm using tetramethylsilane as the internal reference. The infrared spectra (4000–400 cm⁻¹) were recorded on a BIO-RAD FTS 3000MX instrument in KBr pellets. Carbon, hydrogen, and nitrogen elemental analysis was carried out in a PerkinElmer 2400 analyzer. Electrospray mass spectra (ESI-MS) was performed with an ion-trap instrument (Varian 500-MS LC Ion Trap Mass Spectrometer) equipped with an electrospray ion source. For electrospray ionization, the drying gas and flow rate were optimized according to the particular sample with 35 p.s.i. nebulizer pressure. Scanning was performed from m/z 50 to 1000 in a methanol solution. The compounds were observed in the negative or positive mode (capillary voltage = 80–105 V).

Reagents of analytical grade were acquired from Honeywell, Labchem, Sigma-Aldrich and Scharlab. Solvents were dried in consonance with standard methods [45 ]. TLC was performed to monitor chemical reactions using aluminium plates coated with silica gel 60 F₂₅₄ obtained from Merck. Column chromatographic separations were performed with silica gel 60A 70–200 μ obtained from Carlo Erba Reagents. Melting points (M.P.s) were measured using a Leica Galen III hot stage microscope. NMR spectra (¹H and ¹³C) were recorded on a Bruker AVANCE III-300 NMR spectrometer (at 300 and 75 MHz). Standard internal reference of tetramethylsilane (TMS) was employed to report the chemical shifts (δ). The abbreviations used are as follows: s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet. Mass spectra (ESI-MS) were captured with a 500 MS LC Ion Trap mass spectrometer (Varian Inc., Palo Alto, CA, USA) equipped with an ESI ion source, operated in the positive ion mode. High-resolution mass spectra (HRMS) were obtained on a Bruker Impact II quadrupole mass spectrometer (Bruker Daltoniks, Billerica, MA, USA).

Synthesis of compound I and compound II was described in the previous paper [17 (link)] based on the article by Pijewska [42 ]. Both compounds were purified by crystallization from methanol. The structures of compound I and II were characterized using IR, ¹H- and ¹³C-NMR, MS spectroscopy, and elemental analysis. All solvents used in the synthesis were purchased from Sigma-Aldrich (St. Louis, MO, USA) and were used without further purification. The infrared transmission spectra of the crystalline products were recorded using a Nexus Thermo Nicolet FT-IR spectrophotometer (Wien, Austria; Faculty of Chemistry, University of Lodz). The MS-ESI were measured at the University of Lodz Faculty of Chemistry on a 500–MS LC Ion Trap mass spectrometer (Varian, Palo Alto, CA, USA). Elemental analyses were performed in the Faculty of Chemistry (University of Lodz) using a Vario Micro Cube (Langenselbold, Germany) by Elemental analyzer. ¹H- (600 MHz) and ¹³C-NMR spectra (150 MHz) were recorded at the University of Lodz Faculty of Chemistry on a Bruker Avance III instrument (Bruker, Billerica, MA, USA). The samples of compound I and II were dissolved in deuterated DMSO. The chemical shifts are given in ppm, and the coupling constants in Hz. Melting points were determined on a B-540 Melting Point apparatus (Büchi, Flawil, Switzerland) in capillary mode, and they were uncorrected.