400 mr ddr2 spectrometer

Temperature data were uncorrected. NMR spectra were recorded with a Varian MercuryPlus spectrometer (¹H NMR spectra at 299.97 MHz and ¹³C NMR spectra at 75.77 MHz), or with an Agilent 400-MR DDR2 spectrometer (¹H NMR spectra at 399.94 MHz and ¹³C NMR spectra at 100.58 MHz) using the residual deuterated solvent signals as the internal standards. Chemical shifts are given in parts per million and coupling constants in hertz. Mass spectra (ESI, APCI) and HRMS spectra were measured with a hybrid LTQ Obitrap XL instrument (Thermo Fisher Scientific). All reactions were performed in a dry inert atmosphere (Ar) in oven-dried flasks. Anhydrous solvents were obtained from a PureSolv MD7 drying line (Innovation Technologies). N-Phenylmaleimide (13) was prepared according to a literature procedure. [42 (link)]. The syntheses of compounds 2, 4, and 7–11 are given in Supporting Information File 1.

NMR data were acquired on Agilent 400-MR DDR2 spectrometer operating at 400.13 and 100.62 MHz for ¹H and ¹³C, respectively, using deuterated solvents (chloroform and methanol), purchased from Merck KGaA (Darmstadt, Germany). Mass spectra were obtained by Thermo Scientific LTQ Orbitrap Velos—Hybrid Mass Spectrometer Ultimate Confidence (Bremen, Germany), typically in positive electrospray ionization with methanol as sample diluent.

Sample I. was obtained from the now-defunct website Astro-lab.com (10 March 2017). Sample II. was obtained within a collaboration with the Czech border police. A standard of MXP for comparison was prepared using the McLaughlin procedure [15 (link)], which was slightly modified to obtain MXP without any inorganic impurities (see Section 2.4). Chemicals used for the synthesis were obtained from commercial sources (Sigma-Aldrich, St. Louis, MO, USA). Solvents were acquired from commercial sources and were used after distillation. Solvents denoted as dry were dried before use by molecular sieves. Other commercial reagents were used without further purification. The structure of the product was confirmed by ¹H and ¹³C-NMR spectroscopy (400-MR DDR2 spectrometer, Agilent, Santa Clara, CA, USA), deuterated methanol was used as a solvent and the residual signals of the solvent served as an internal standard. The diethyl ether solution of hydrochloride was prepared from commercial diethyl ether, commercial concentrated hydrochloric acid, and calcium chloride as drying agents.