Niko Radulović

SYNTHESIS, COMPLETE ASSIGNMENT OF 1H- AND 13C-NMR SPECTRA AND ANTIOXIDANT ACTIVITY OF NEW AZINE DERIVATIVE BEARING COUMARIN MOIETY

In this research, the synthesis of a new azine derivative with coumarin moiety was performed in three reaction steps, starting from 4-hydroxycoumarin. The first step in synthesis was the acetylation of 4-hydroxycoumarin to yield 3-acetyl-4-hydroxycoumarin and then the obtained 3-acetyl-4-hydroxycoumarin was reacted with hydrazine hydrate and give a corresponding hydrazone. Condensation of the hydrazone with 4-ethoxy-3-methoxybenzaldehyde afforded the target compound 1-[1-(4-hydroxy-2-oxo-2H-chromen-3-yl)-ethylidene]-2-(4-etoxy-3-methoxybenzylidene)-hydrazine in a good yield. The resulting azine derivative is fully spectrally characterized, including complete assignment of 1H- and 13C-NMR spectra, as well as 2D NMR (1H-1H COSY, NOESY, HSQC and HMBC) spectra. The antioxidant activity of corresponding hydrazone and target compound was evaluated by DPPH method where hydrazone derivative displayed a significant and target azine good antioxidant activity, with IC50 (μM) values 11.69 and 216.60, respectively.

SYNTHESIS AND COMPLETE NMR SPECTRAL ASSIGNMENTS OF NEW BENZYLAMINO COUMARIN DERIVATIVE

This research involves the reaction of 4-chloro-3-nitrocoumarin and (4-methoxyphenyl)methanamine, whereby a novel coumarin derivative 4-[(4-methoxybenzyl) amino]-3-nitro-2H-chromen-2-one was obtained in good yield. The reaction was carried out in ethyl acetate, in the presence of triethylamine. Also, a detailed spectral analysis of a new coumarin derivative is presented. Resonance assignment was achieved using one- (1H NMR and 13C NMR) and two-dimensional NMR techniques (1H-1H-COSY, NOESY, HSQC, and HMBC). The NOESY correlations of protons from arylamino substituent and coumarin core indicate their spatial orientation.

THE SYNTHESIS AND NMR SPECTRAL ASSIGNMENTS OF 3-NITRO-4-((6-NITROBENZOTHIAZOL-2-YL)AMINO)-2H-CHROMEN-2-ONE

Complete assignment of the 1H and 13C NMR chemical shifts of new coumarin derivate was described in this paper. A new coumarin derivate was synthesized in good yield by reaction of 4-chloro-3-nitrocoumarin and 6-nitrobenzothiazol-2-amine in ethyl acetate in the presence of triethylamine. The complete spectral assignment was achieved using of 1D (1H and 13C NMR) and 2D (1H-1H-COSY, NOESY, HSQC and HMBC) NMR experiments.

SYNTHESIS AND ANTIOXIDANT ACTIVITY OF A NEW 4-AMINOCOUMARIN DERIVATIVE