Thermo scientific q exactive plus hybrid quadrupole orbitrap

Melting points were determined on a Hinotek X-4 melting point apparatus. Merck Kieselgel 60F₂₅₄ plates were applied for TLC. Microwave reactions were carried out with a CEM Discover SP microwave reactor.
¹H and ¹³C NMR spectra were recorded in DMSO-d₆ solutions in 5 mm tubes at room temperature (RT), on a Bruker DRX-500 spectrometer (Bruker Biospin, Karlsruhe, Baden Wurttemberg, Germany) at 500 (¹H) and 125 (¹³C) MHz, with the deuterium signal of the solvent as the lock and TMS as internal standard (¹H, ¹³C). All spectra (¹H, ¹³C) were acquired and processed with the standard BRUKER software.
The HRMS flow injection analysis was performed with Thermo Scientific Q Exactive Plus hybrid quadrupole-Orbitrap (Thermo Fisher Scientific, Waltham, MA, USA) mass spectrometer coupled to a Waters Acquity I-Class UPLC™ (Waters, Manchester, UK).
The intermediate enamines dimethyl and diethyl 3-(phenylimino)pentanedioate (3a and 3b) were synthesised according to literature methods [18 (link),19 ,23 ,40 (link),41 (link),42 (link),43 ].

¹H and ¹³C-NMR spectra were recorded in DMSO-d₆ and CDCl₃ solutions in 5 mm tubes at room temperature (RT), on a Bruker DRX-500 spectrometer (Bruker Biospin, Karlsruhe, Baden Württemberg, Germany) at 500 (1H) and 125 (13C) MHz, with the deuterium signal of the solvent as the lock and TMS as internal standard (1H, 13C).
Melting points were determined on a Hinotek X-4 melting point apparatus. Merck Kieselgel 60F₂₅₄ plates were used for TLC.
HRMS flow injection analysis was performed with Thermo Scientific Q Exactive Plus hybrid quadrupole-Orbitrap (Thermo Fisher Scientific, Waltham, MA, USA) mass spectrometer coupled to a Waters Acquity I-Class UPLC™ (Waters, Manchester, UK).
The synthesis of compounds 16a was carried out according to literature method [45 (link)].