Dpx 75 mhz spectrometer

All chemicals were purchased
from Sigma-Aldrich Chemical Co. (Sigma-Aldrich Corp., St. Louis, MO)
and Merck Chemicals (Merck KGaA, Darmstadt, Germany). All melting
points (m.p.) were determined by an MP90 digital melting point apparatus
(Mettler Toledo, Ohio) and were uncorrected. All reactions were monitored
by thin-layer chromatography (TLC) using Silica Gel 60 F254 TLC plates
(Merck KGaA, Darmstadt, Germany). Spectroscopic data were recorded
with the following instruments: ¹H nuclear magnetic resonance
(NMR) Bruker DPX-300 FT NMR spectrometer, ¹³C NMR, Bruker
DPX 75 MHz spectrometer (Bruker Bioscience, Billerica, MA); mass (high-resolution
mass spectrometry (HRMS)) spectra were recorded on a liquid chromatography
connected with hybrid ion-trap and time-of-flight mass spectrometry
(Shimadzu) using electrospray ionization.

All reagents were purchased from commercial suppliers and were used without further purification. Melting points (M.p.) were determined using the Mettler Toledo-MP90 Melting Point System and were uncorrected. A ¹H-NMR (nuclear magnetic resonance) Bruker DPX 300 FT-NMR spectrometer and a ¹³C-NMR, Bruker DPX 75 MHz spectrometer (Bruker Bioscience, Billerica, MA, USA) were used. A total of 10 mg of compound was weighed and dissolved in 600 µL of DMSO-d₆. In this way, the NMR procedure was carried out. Mass spectra were recorded on an LCMS-IT-TOF (Shimadzu, Kyoto, Japan) using ESI. In total, 10 mg of compound was weighed and dissolved in 1500 µL of MeOH. In this way, the HRMS procedure was carried out.