Chns o ea 1108

Reagents, starting materials and solvents were obtained from commercial sources and used as received. Thin-layer chromatography was performed on silica gel, spots were visualised with UV light (254 and 365 nm). Melting points were determined on an OptiMelt automated melting point system. IR spectra were recorded on Shimadzu FTIR IR Prestige-21 spectrometer. NMR spectra were recorded on Bruker Avance Neo (400 MHz) spectrometer with chemical shifts values (δ) in ppm relative to TMS using the residual CDCl₃ signal (¹H 7.26; ¹³C 77.16) as an internal standard. High-resolution mass spectra (HRMS) were recorded on a mass spectrometer with a Q-TOF micro mass analyser using the ESI technique. Elemental analyses were performed on Carlo Erba CHNS-O EA-1108 apparatus. GC-MS analyses were performed on Agilent Technologies 7890 A gas chromatograph, column – HP-5HS (df = 0,25 μm, ID = 0,25 mm, length − 30 m) with Agilent Technologies 5975 C masselective detector.

The ¹ H NMR and ¹³C NMR spectra were recorded on Agilent 400-MR (400 MHz) and Bruker Avance-600 spectrometers (600 MHz) in CDCl₃ or DMSO-d₆ using tetramethylsilane (TMS) as internal standard. The chemical shifts were reported in δ scale, and constant J values are presented in Hz. IR spectra were recorded on a UR-20 instrument in Nujol and on an IR-200 Fourier-transform IR spectrometer (TermoNicolet, Waltham, MA, USA) with a resolution of 4 cm⁻¹ (KBr pellets). Electrospray ionization (ESI) high-resolution mass spectra were recorded on a Bruker maXis instrument. Melting points were measured on an Electrothermal IA 9000 series device in glass capillaries. Elemental analysis was performed on a Carlo Erba device EA 1108CHNS-O. The TLC on Silufol UV-254 was used to follow the course of reactions. Compound purification was performed using short dry column or flash-chromatography on silica gel (60, Fluka, Honeywell Research Chemicals, Morris Plains, NJ, USA) [81 (link)]. Started indole derivatives were used as purchased from Sigma-Aldrich. The 5-Hydroxy-1-phenylimidazolidin-2-one, 1 was obtained according to the procedure [61 (link)]. Solvents were purified by standard methods.

For lignosulfonates, determining
sulfonic acid groups was performed indirectly as the sulfur content
by elemental analysis at the Laboratory for Microanalysis Services
at the University of Vienna. Prior to analysis, the samples were thoroughly
dried in a vacuum oven at 40 °C and stored in an inert atmosphere.
Elemental analysis was conducted as C/H/N/S analyses (oxygen was determined
indirectly) on an EA 1108 CHNS-O elemental analyzer (CarloErba Instruments,
CE Elantech, Inc.).³⁸

The determination of C/H/N/O/Cl was carried out using an ‘EA 1108 CHNS-O’ elemental analyzer by Carlo Erba Instruments at the Mikroanalytisches Laboratorium, University of Vienna.