3,4-Disubstituted derivatives of 1,2,5-thiadiazole 1,1-dioxide. Ethanol addition reactions and electroreduction of 3-methyl-4-phenyl and 3,4-dimethyl derivatives in acetonitrile and ethanol solvents

Author:

Caram José Alberto,Mirífico María Virginia,Aimone Silvia Lucía,Vasini Enrique Julio

Abstract

3-Methyl-4-phenyl-1,2,5-thiadiazole 1,1-dioxide (TMP), as well as 3,4-dimethyl-1,2,5-thiadiazole 1,1-dioxide (TMM), react with ethanol (EtOH), which adds to one of their C = N double bonds. The equilibrium constants for the addition reaction are measured in mixed acetonitrile (ACN) – EtOH solvents by means of UV spectroscopy in the case of TMP, and by 13C NMR spectroscopy in the case of TMM, since TMM presents only terminal UV absorption. Both equilibrium constants are also estimated through cyclic voltammetry (CV) experiments. In the case of TMP, the ethanol molecule adds to the C = N bond located on the methyl-substituted side of the substrate, according to 13C NMR spectroscopy and CV results. The electroreduction characteristics of the substrates and their ethanol addition products are studied using CV techniques in ACN, EtOH, and CAN–EtOH solvent mixtures. The radical anion formed by the first electron transfer to TMM is unstable and decomposes rapidly while that corresponding to TMP undergoes a relatively slow homogeneous second-order reaction with the substrate (k = 3 × 102 M−1 s−1). The equilibrium constant for EtOH addition and the voltammetric properties of the substrates are compared with those of the previously studied 3,4-diphenyl derivative (TPP). Key words: electrochemistry, thiadiazoles, structure–reactivity relations, kinetics.

Publisher

Canadian Science Publishing

Subject

Organic Chemistry,General Chemistry,Catalysis

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3