Este trabalho apresenta o estudo do comportamento eletroquímico de cinamatos de metila sulfenilados: o 3-feniltio-3-fenil-propenoato de metila, 2-feniltio-3-fenil-propenoato de metila, 3-fenil-3-etiltio-propenoato de metila e 2-etiltio-3-fenil-proenoato de metila. Está incluído a síntese dos substratos, a voltametria e as eletrólises preparativas, abrangendo oxidações e reduções eletroquímicas. As sínteses de três dos quatro ésteres selecionados partiram de um mesmo intermediário, o 3-fenil-propinato de metila, através de reações de Michael e radicalares com etanotiol e tiofenol. O 2-etiltio-3-fenil-propenoato de metila foi obtido a partir do ácido 2-etiltio-acético. As reduções catódicas foram feitas usando-se cela dividida, acetonitrila ou DMF anidros como solventes, mercúrio como eletrodo de trabalho, atmosfera inerte e potencial fixo. Em alguns casos foi utilizado uma mistura de acetonitrila com metanol como solvente, e também cela de compartimento único. Houve uma distinção entre os produtos obtidos das eletrólises dos cinamatos α e β-sulfenilados. Para os primeiros, predominou a saída do grupo do enxofre, formando cinamato de metla, ácidos cinâmico, éster de partida hidrogenado, ciclopentanonas e adipatos de metila acíclicos. Os outros dois α-isômeros não mostraram a mesma facilidade de quebra da ligação carbono-enxofre, levando a produtos de hidrólise, ciclopentanonas e derivados de hexanoatos que mantiveram os grupos sulfenilados As oxidações anódicas foram feitas em celas de compartimento único e separados, usando platina como eletrodo de trabalho, atmosfera inerte e corrente controlada. A maior parte dos experimentos ocorreu em meio reacional prótico (acetonitrila/metanol), fornecendo ésteres di e trimetoxilados, α e β-ésteres e tioacetais (com etiltio e feniltio) / This work presents the studing of electrochemical behavior of sulfenyl cinnamates: the 3-phenyl-3-phenylthio-propenoic methyl ester, 2-phenyl-3-phenyl-propenoic methyl-ester, 3-phenyl-3-ethylthio-propenoic methyl ester, 2-ethylthio-3-phenyl-propenoic methyl ester. The overall plane includes the synthesis of substrates, the cyclic voltammetry and the preparative eletrolysis, enclosing the reductions and oxidations. The synthesis of the three among the four chosen esters came from the same compound, the 3-phenyl-propenoic methyl ester, by Michael and radicals reactions with ethanethyol and thiophenol. The 2-ethylthio-propenoic methyl ester was achieved from the 2-ethylthio-acetic acid. The cathodic reductions werw carried out in divided glass cells, dry acetonitrile or DMF as solvents, mercury as work electrode, inert atmosphere and controlled potential. In some cases, was used a mixture of acetonitrile and methanol and only one experiment was performed in undivided cell. The products formed in β and α-sulfenyl substrates were not equal, because to the first the main role was the cleavage of the sulfur-carbon bond, giving methyl cinnamate ester, cinnamic acid, starting materials hydrogenateds, cyclopentanone and adipates derivatives. The others two isomers not exhibit the loss of sulfur group, forming hydrolisis products, cyclopentanones and hexanoates derivatives what keeping the sulfenyl groups. The anodic oxidations was carried out in divided and undivided glass cells, with platine as work electrode, inert atmosphere and controlled current Most of the electrochemicals reactions were run in protic reactional middle (acetonitrile/methanol), to furhter di and trimethoxylateds esters, β-keto-esters and thioketals (both ethyl and phenylthio).

Este trabalho apresenta o estudo do comportamento eletroquímico de cinamatos de metila sulfenilados: o 3-feniltio-3-fenil-propenoato de metila, 2-feniltio-3-fenil-propenoato de metila, 3-fenil-3-etiltio-propenoato de metila e 2-etiltio-3-fenil-proenoato de metila. Está incluído a síntese dos substratos, a voltametria e as eletrólises preparativas, abrangendo oxidações e reduções eletroquímicas. As sínteses de três dos quatro ésteres selecionados partiram de um mesmo intermediário, o 3-fenil-propinato de metila, através de reações de Michael e radicalares com etanotiol e tiofenol. O 2-etiltio-3-fenil-propenoato de metila foi obtido a partir do ácido 2-etiltio-acético. As reduções catódicas foram feitas usando-se cela dividida, acetonitrila ou DMF anidros como solventes, mercúrio como eletrodo de trabalho, atmosfera inerte e potencial fixo. Em alguns casos foi utilizado uma mistura de acetonitrila com metanol como solvente, e também cela de compartimento único. Houve uma distinção entre os produtos obtidos das eletrólises dos cinamatos α e β-sulfenilados. Para os primeiros, predominou a saída do grupo do enxofre, formando cinamato de metla, ácidos cinâmico, éster de partida hidrogenado, ciclopentanonas e adipatos de metila acíclicos. Os outros dois α-isômeros não mostraram a mesma facilidade de quebra da ligação carbono-enxofre, levando a produtos de hidrólise, ciclopentanonas e derivados de hexanoatos que mantiveram os grupos sulfenilados As oxidações anódicas foram feitas em celas de compartimento único e separados, usando platina como eletrodo de trabalho, atmosfera inerte e corrente controlada. A maior parte dos experimentos ocorreu em meio reacional prótico (acetonitrila/metanol), fornecendo ésteres di e trimetoxilados, α e β-ésteres e tioacetais (com etiltio e feniltio) / This work presents the studing of electrochemical behavior of sulfenyl cinnamates: the 3-phenyl-3-phenylthio-propenoic methyl ester, 2-phenyl-3-phenyl-propenoic methyl-ester, 3-phenyl-3-ethylthio-propenoic methyl ester, 2-ethylthio-3-phenyl-propenoic methyl ester. The overall plane includes the synthesis of substrates, the cyclic voltammetry and the preparative eletrolysis, enclosing the reductions and oxidations. The synthesis of the three among the four chosen esters came from the same compound, the 3-phenyl-propenoic methyl ester, by Michael and radicals reactions with ethanethyol and thiophenol. The 2-ethylthio-propenoic methyl ester was achieved from the 2-ethylthio-acetic acid. The cathodic reductions werw carried out in divided glass cells, dry acetonitrile or DMF as solvents, mercury as work electrode, inert atmosphere and controlled potential. In some cases, was used a mixture of acetonitrile and methanol and only one experiment was performed in undivided cell. The products formed in β and α-sulfenyl substrates were not equal, because to the first the main role was the cleavage of the sulfur-carbon bond, giving methyl cinnamate ester, cinnamic acid, starting materials hydrogenateds, cyclopentanone and adipates derivatives. The others two isomers not exhibit the loss of sulfur group, forming hydrolisis products, cyclopentanones and hexanoates derivatives what keeping the sulfenyl groups. The anodic oxidations was carried out in divided and undivided glass cells, with platine as work electrode, inert atmosphere and controlled current Most of the electrochemicals reactions were run in protic reactional middle (acetonitrile/methanol), to furhter di and trimethoxylateds esters, β-keto-esters and thioketals (both ethyl and phenylthio).

Объектом исследования являлось вещество натриевая соль 2-этилтио-6-нитро-1,2,4-триазоло-[5,1-c]-1,2,4-триазин-7-она, дигидрат (УПИ-802). Цель работы: количественное определение лекарственного вещества натриевой соли 2-этилтио-6-нитро-1,2,4-триазоло-[5,1-c]-1,2,4-триазин-7-она дигидрата методом вольтамперометрии. В случае УПИ-802 наиболее полезным для количественного определения является сигнал электровосстановления нитрогруппы. Исследованы процессы восстановления нитрогруппы исследуемого вещества в водных и апротонных растворах с применением вольтамперометрии в условиях физического удаления растворенного кислорода и без удаления кислорода. Установлено, что скорость восстановления УПИ-802 контролируется диффузией, процесс восстановления нитрогруппы является необратимым и проходит в две стадии в буферном растворе Бриттона-Робинсона. Первая волна восстановления, которая лежит в области потенциалов -0,31 – (-0,8) В, соответствует присоединению 4 электронов. Обнаружено, что электровосстановление нитрогруппы протекает с предшествующим протонированием. Выбран оптимальный режим регистрации аналитического сигнала исследуемого вещества УПИ-802 на стеклоуглеродном электроде в условиях химического способа удаления растворенного кислорода – квадратно-волновой с амплитудой импульса 0,05 В, частотой импульса 35 Гц. Показана возможность применения толстопленочных углеродсодержащих электродов для определения исследуемого вещества методом квадратно-волновой вольтамперометрии. Выполнена оценка показателей качества методики анализа, таких как линейность, повторяемость (сходимость) и внутрилабораторная прецизионность. / The object of the study was the substance 2-ethylthio-6-nitro-1,2,4-triazolo-[5,1-c]-1,2,4-triazin-7-one sodium salt dihydrate (UPI-802). Objective: quantification of 2-ethylthio-6-nitro-1,2,4-triazolo-[5,1-c]-1,2,4-triazin-7-one sodium salt dihydrate by the method of voltammetry. For UPI-802, the signal of electroreduction of a nitro group is the most useful for quantitative determination. The processes of the nitro group reduction of the test substance in aqueous and aprotic solutions was studied using voltammetry in conditions of physical removal of dissolved oxygen and without oxygen removal. It was established that the rate of reduction of UPI-802 is controlled by diffusion, the processes of reduction of the nitro group is irreversible and proceeds in two stages in a Britton-Robinson buffer solution. The first recovery wave, lying in the potential region of -0,31 - (-0,8) V, corresponds to the addition of 4 electrons. It was found that the electroreduction of the nitro group proceeds with previous protonation. The optimal mode for recording the analytical signal of the UPI-802 on the glassy carbon electrode was selected in conditions of chemical method for removing dissolved oxygen – square-wave with a pulse amplitude of 0,05 V and a pulse frequency of 35 Hz. The possibility of using thick-film carbon-containing electrodes to determine the test substance by the method of square-wave voltammetry was shown. The quality indicators of the analysis technique, such as linearity, repeatability (convergence) and intralaboratory precision, were evaluated.