Synthesis, properties and color assessment of some new 5-(3- and 4-substituted phenylazo)-4,6-dimethyl-3-cyano-2-pyridones

Abstract

A series of 5-(3- and 4-substituted phenylazo)-4,6-dimethyl-3-cyano-2-pyridones were synthesized, starting from acetylacetone and arenediazonium salt, followed by condensation with cyanoacetamide using a modified literature procedure. The experimental investigation included modification of the synthetic procedure in terms of solvent, temperature, isolation techniques as well as purification and identification of the products. The azo dyes were characterized by melting point, IR, UV/Vis, 1H NMR and MS data. HPLC analyses were also performed. The 2-hydroxypyridine/ 2-pyridone tautomeric equilibration was found to depend on the polarity of the applied solvents. A color assessment of the solid dyes and dyed polyester fabrics was also performed and the correlation between the colour and the structure of the dyes is discussed.

Rapid and Simple Spectrophotometric Determination of Mn(II), Fe(III), Co(II), Ni(II) and Cu(II) Ions in Natural Samples Using 2-(2-Hydroxynaphth-1-ylazo)-pyridine

“…This CT band appears as band and a shoulder at 450-465 and 408-415 nm, respectively. This may be attributed to the existence of azo-hydrazone tautomeric equilibrium originating from the OH group in o-position to the N=N center which can be represented as given in scheme 1 (1,19) . The CT band resulting from the absorption region of the lower energy site is due to the hydroxyl-azo form (A), while that at higher energy region may be attributed to the absorption by the oquinone hydrazone (B) species (1,20) .…”

Recent advances in synthesis of 2-pyridones: a key heterocycle is revisited

“…In recent decades, 2-pyridone and its derivatives have attracted remarkable attention, because of their extensive applications in many fields such as biology [1][2][3][4][5][6][7] natural products [8,9], dyes [10][11][12], and fluorescents [13]. These wide utilities and waves of interest on the 2-pyridone as a key heterocycle, encouraged us to look for the new developments in the synthesis of 2-pyridone in recent years.…”

Synthesis of 5-(substituted phenylazo)-6-hydroxy-4-methyl-3- cyano-2-pyridones from ethyl 3-oxo-2-(substituted phenyldiazenyl)butanoates

“…1,2 Pyridone disperse yellow dyes, such as C.I. 17,18 Recently, a microwave procedure for the synthesis of azo pyridone dyes using the second reaction route was reported. 3,4 The conventional reaction route for the preparation of these azo dyes comprises the reaction of pyridone as a coupling component and various diazonium salts.…”