4-formyl-3-hydroxy-2-naphtoic acid (1) was treated with ethanol in benzene
in the presence of H2SO4 and ethyl–2-hydroxy-4-formyl-2-naphtoate (2) has
been synthesized.

By treatment of (2) with ethylenediamine in ethanolic media and
Ni(ClO4)2
.6H2O, consecutively, in molar ratio 1:1:1 a red crystals were obtained.
The composition of synthesized compounds has been established by elemental
analysis, IR and NMR spectroscopy (for ligands).
The 13C and 1H NMR spectra reveals the esterification of 4-formyl-3-hydroxy-
2-naphtoic acid.
1H-NMR (DMSO): δ 1.05-1.14, t, 3H(CH3); 3.31-3.37, m, 2H(CH2) ppm.
IR spectra: The absorption band at 1600 cm-1 is assignable to the ν(C=N)
stretching mod. IR spectra of (3) show the strong band due to the ν(C=O) of the
ester group at 1700 cm-1. Because of intramolecular hydrogen bonds, ν(C=O) of
ester group for ligand (2) appears as a shoulders at 1615-1650 cm-1 [1].
References
1.L. J. Bellamy. Advances in Infrared Group Frequencies. M.: Mir, 1971. 318p.
(rus).