Spectrophotometry of 4-(4-imino-2-oxo-thiazolidine-5-ilazo)-benzoic acid

Abstract

4-Azolidones is effective scaffold for drug-like molecules design in modern medicinal chemistry and have become widely pharmaceutical use, due to their low toxicity and wide spectrum of biological effects (show antitumor, anti-inflammatory, antifungal, antibacterial, antiviral, antituberculosiсal, hypoglycemic, hepatoprotective action and promising anti-HIV agents). Therefore, the development of methods for controlling the content of substances of this class in different substrates is an actual direction of modern research. For the first time the chemical-analytical characteristics of a new reagent of 4-(4-imino-2-oxo-thiazolidine-5-ilazo)-benzoic acid, which is a representative of the class of azolidones, has been investigated. This reagent is poorly soluble in water and ethanol, but is readily soluble in dimethylformamide and dimethyl sulfoxide. The influence of the media acidity on the appearance of absorption spectra of 4-(4-imino-2-oxo-thiazolidine-5-ilazo)-benzoic acid solutions has been investigated. The form of absorption spectra of this reagent is practically independent of the acidity of the medium. It has been determined that at pH > 10.0 the hydrolysis of the imino group occurs. The 4-(4-imino-2-oxo-thiazolidine-5-ilazo)-benzoic acid does not form tautomeric forms and does not polymerize in the concentration range 5.0·10 -6 –8.0·10 -5 mol/L. The average values of the effective molar absorption coefficients of this derivative azolidone at the wavelength of 390 nm, which lies in the range from 3.0·10 3 to 2.40·10 4 L·mol -1 ·cm -1 , depending on the acidity of the medium, have been calculated. A method for determining this reagent by its own absorption has been developed. The linear range for the determination of the 4-(4-imino-2-oxo-thiazolidine-5-ilazo)-benzoic acid using the spectrophotometric method at pH=7.0 and λ=390 nm lies within 1.0·10 -6 to 6.0·10 -5 mol/L. Keywords : 4-(4-imino-2-oxo-thiazolidine-5-ilazo)-benzoic acid, azolidones, spectrophotometry.