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There was studied protonation of aminothiazoles of mineral acids of different strength in order to research the basicity of nitrogen atoms of free amino group and nitrogen of thiazole ring. The results obtained showed high ambidentity of 2-amino-4-phenylthiazole and 2-amino-4-oxothiazole associated with a high degree of delocalization of both the lone pair of electrons of the amino group and the thiazole ring nitrogen atom which creates opportunities for chemical modification of the aminoheterocycles with the free amino group and the ring nitrogen atom. Complexing ability of 2-amino-4-oxothiazole with cobalt (II) chloride caused by high degree of basicity of cyclic nitrogen atom was also studied.
It is known that interest to heterocyclic compounds is associated with a wide variety of biologically active properties characteristic for representatives of this class. In particular it does not cease the interest to azaheterocyclic compounds, including derivatives of thiazole, having great importance for the pharmaceutical industry, biochemistry, technology, clinical and experimental medicine. Thiazole derivatives possess antiviral, antiparasitic, antipyretic, antihemolytic, antihypertensive properties and are widely used in medical practice [1]. They are also used in engineering as effective components of the polymeric materials which increase their stability, possess the ability to inhibit the oxidation and corrosion processes, and exhibit complexing properties.
Among practically important thiazole derivatives mercaptothiazoles used as vulcanization accelerators in the rubber industry are well known [2].
Continuing investigations in the field of search and the synthesis of new interesting in practical terms thiazole derivatives, it seems interesting for us to continue researching the structural features of this class of compounds due to the dual reactivity. In this aspect as subjects of research we selected 2-aminothiazole derivatives known to have great importance for the pharmaceutical industry, biochemistry, technology, clinical and experimental medicine. A feature of these compounds is associated with the presence of the free amino group and a nitrogen atom of the heterocycle.
Among the best known amine derivatives of thiazole are 2- and 5-aminothiazoles which can exist in two tautomeric forms but with an evident predominance of the amino form that creates opportunities for their experimental studies aimed at the synthesis of compounds with practically useful properties.
2-Amino-4-phenylthiazolc and 2-amino-4-oxothiazole were chosen as subjects of this study. These compounds are characterized by a number of structural...