da Silva Ramon S, Sangi Diego P, Amorim Rodrigo G
Departamento de Física - Instituto de Ciências Exatas - ICEx, Universidade Federal Fluminense, Volta Redonda, Rio de janeiro 27213-145,Brazil.
Departamento de Química - Instituto de Ciências Exatas - ICEx, Universidade Federal Fluminense, Volta Redonda, Rio de janeiro 27213-145,Brazil.
ACS Omega. 2024 Dec 21;10(1):995-1005. doi: 10.1021/acsomega.4c08242. eCollection 2025 Jan 14.
Ketene dithioacetals have significant applications in various fields, including natural products, pharmaceuticals, agrochemicals, and corrosion inhibitors. These compounds are highly valued for their reactivity and ability to participate in a wide range of organic syntheses. In this context, the reaction between 1,3-diaminopropan-2-ol and 1,1-bismethylsulfanyl-2-nitroethylene has been studied experimentally and theoretically by using density functional theory (DFT) calculations. A theoretical mechanism of formation of two possible products, 2-(nitromethylene)hexahydropyrimidin-5-ol (with a six-membered heterocycle) and (2-(nitromethylene)oxazolidin-5-yl)methanamine (with a five-membered heterocycle), is for the first time predicted. The present DFT results indicate that both mechanisms are exothermic, with energy barriers approximately 20 kcal/mol higher than those of the reactants. Among the two, the formation of 2-(nitromethylene)hexahydropyrimidin-5-ol is energetically more favorable. This compound was synthesized and analyzed by different experimental techniques (IR, nuclear magnetic resonance (NMR), and high-resolution mass spectrometry). The H and C NMR chemical shifts of 2-(nitromethylene)hexahydropyrimidin-5-ol were calculated using the GIAO/B3LYP, showing good agreement with our experimental observations. These findings highlight an important match between experimental results and theoretical predictions, offering deeper insights into ketene dithioacetal reactions. The new data and contributions are expected to generate significant interest in future applications.
乙烯酮二硫代缩醛在包括天然产物、药物、农用化学品和腐蚀抑制剂在内的各个领域都有重要应用。这些化合物因其反应活性以及参与各种有机合成的能力而备受重视。在此背景下，通过密度泛函理论（DFT）计算，对1,3 - 二氨基丙 - 2 - 醇与1,1 - 双甲基硫烷基 - 2 - 硝基乙烯之间的反应进行了实验和理论研究。首次预测了两种可能产物2 - （硝基亚甲基）六氢嘧啶 - 5 - 醇（含六元杂环）和（2 - （硝基亚甲基）恶唑烷 - 5 - 基）甲胺（含五元杂环）形成的理论机制。目前的DFT结果表明，两种机制都是放热的，能垒比反应物的能垒高约20千卡/摩尔。在这两者中，2 - （硝基亚甲基）六氢嘧啶 - 5 - 醇的形成在能量上更有利。通过不同的实验技术（红外光谱、核磁共振（NMR）和高分辨率质谱）对该化合物进行了合成和分析。使用GIAO/B3LYP计算了2 - （硝基亚甲基）六氢嘧啶 - 5 - 醇的H和C NMR化学位移，与我们的实验观察结果显示出良好的一致性。这些发现突出了实验结果与理论预测之间的重要匹配，为乙烯酮二硫代缩醛反应提供了更深入的见解。新的数据和贡献有望在未来的应用中引起极大的兴趣。
