Synthesis and antioxidant properties of new (2,4- and 3,4-dimethoxyphenyl)-1,2,4-triazoles

The purpose of the work is to develop preparative methods for the synthesis of ((5-(2,4and 3,4-dimethoxyphenyl)-3H-1,2,4-triazole-3-yl)thio)aceto(propano-, butano-, benzo)nitriles, to investigate the reaction of acid hydrolysis, to receive the physical-chemical properties of the synthesized compounds, and to study antioxidant activity of new compounds. Preparative methods for the synthesis of (5-(2,4and 3,4-dimethoxyphenyl)-3H-1,2,4-triazole-3-yl)thio)aceto(propano-, butano-, benzo)nitriles have been developed for which studied the reaction of acid hydrolysis, resulting in the production of carboxylic acids. The structure of the obtained substances was confirmed by modern physical-chemical methods. The antioxidant activity of the synthesized compounds was evaluated in vitro by the method of the non-enzymatic initiation of BOD with salts of iron (II).


Introduction
In the 21 st century, pharmacy is very popular and advanced science all over the world. There are many medicines with different pharmacological activities, but not even enough. Therefore, the search, synthesis, and implementation of new drugs with a wide range of biological activity and low toxicity is currently an urgent task of pharmacy.
The works of ZSMU scientific school based on dissertations (Kaplaushenko 2008;Samelyuk 2016) and articles (Kaplaushenko 2013;Hulina and Kaplaushenko 2018) show that the discussed class of compounds serves as a basis for the creation of potential original drugs, with some already being actively used in medicine.
It is known that hydrolysis of nitriles can be performed by two methods: alkaline and acid hydrolysis. Considering the work of scientists (Kaplaushenko 2013;Samely-uk and Kaplaushenko 2015;Shcherbyna 2019), it can be concluded that in acid hydrolysis the target product is obtained with a higher percentage of yield. Therefore, we subsequently studied the reaction of acid hydrolysis for aceto(propano-, benzo)nitriles, resulting in acid.

Toxicity
At the first stage of the study of biological activity of the derivatives of 5- (2,4-and 3,4-dimethoxyphenyl)-3H-1,2,4-triazole-3-thione the acute prediction of toxicity was performed with the program GUSAR-online. It was done to weed out potentially toxic substances as unpromising objects experimental pharmacological screening. Computer prediction of acute toxicity of the derivatives of 5-(2,4-and 3,4-dimethoxyphenyl)-3H-1,2,4-triazole-3-thione were carried out according to structural formulas compounds in the online version of GUSAR-online.

Antioxidant activity
The method of evaluation of AOA was used in the non-enzymatic initiation of BOD with salts of iron (II) (Pruglo 2017). It has been chosen this method because it was the most accessible. With this method, antioxidant activity can be determined without animals. Also, the method of evaluation of AOA has made it possible to predict antihypoxic and antiischemic activity. For such drugs as Trifuzol, Avestim, Thiotriazolin, Thiometrizol, and many others, this research method was also used (Bushueva et al. 2017).
The egg lipoprotein suspension (ELS) was used as the substrate. ELS was prepared by homogenizing egg yolk with phosphate buffer (pH = 7.4). To the suspension was added the test compounds at a concentration of 10-3 mol / l. The free radical oxidation reaction is initiated by the addition of FeSO 4 × 7H 2 O solution. The mixture was incubated for 60 min at 37 °C. The reaction was stopped with a 20% solution of trichloroacetic acid with trilon B. After centrifugation for 30 min. a solution of thiobarbituric acid (TBA) was added to the supernatant and boiled in a water bath for 60 minutes. The colored complex of TBA-active products (TBA -AP) is extracted with the addition of n-butanol. Spec-trophotometry determines the concentration of TBK-AP. Antioxidant activity (in percent) is determined by the formula: where AOA -antioxidant activity, % E 0 -the optical density of the control solution; E 1 -the optical density of a solution containing the test compound (vitamin C).
The identity of the synthesized compounds was proved by chromatographic mass spectrometry. However, only one peak corresponding to the molecular weight of the product of the interaction m \ z + (+1 amp) was detected (Figs 4,5).
In future research, we plan to carry out the synthesis of the derivatives of ((5-(2,4-and 3,4-dimethoxyphenyl)-3H-1,2,4-triazole-3-yl)thio)aceto(propanoic, benzoic)acids, such as salts and esters. As the analysis of the previous works of our scientific school of ZSMU (Kaplaushenko 2008;Samelyuk 2016) was shown that salts and esters were exhibited the highest indicators of antioxidant activity. Salts were showed high performance, but short-term activity. Esters had a longer-lasting effect but had not high enough.