Synthesis, complete assignment of 1H- and 13C-NMR spectra and antioxidant activity of new azine derivative bearing coumarin moiety

Abstract

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-3methoxybenzaldehyde afforded the target compound 1-[1-(4-hydroxy-2-oxo-2H-chromen-3-yl)-ethylidene]-2-(4etoxy-3-methoxybenzylidene)-hydrazine in a good yield. The resulting azine derivative is fully spectrally characterized, including complete assignment of 1Hand 13C-NMR spectra, as well as 2D NMR (1H1H 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 (mM) values 11.69 and 216.60, respectively.