Iraqi National Journal Of Chemistry

In this study, formazans were synthesized by reacting malic acid with vanillin to produce a diester containing two aldehyde groups. The resulting diester was then reacted with a primary amine (4-bromoaniline) to form Schiff bases. These compounds are widely used in the manufacture of certain pharmaceuticals, insecticides, and other industrial products. Subsequently, sodium nitrite was reacted with 4-chloroaniline, 2,4-dinitrophenylhydrazone, and 4-nitroaniline in a 1:1 ratio in the presence of hydrochloric acid and water under ice-bath conditions to generate diazonium salts. The freshly prepared diazonium salts were then coupled with the previously synthesized Schiff bases in the presence of pyridine, followed by drying to obtain the desired formazans. Other formazan derivatives were synthesized using the same procedure. The reactions were monitored by HPLC, and the synthesized compounds were characterized by FT-IR, ¹H NMR, ¹³C NMR, mass spectrometry, and biological activity studies.