Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, 560 012, India.
Org Biomol Chem. 2011 Nov 7;9(21):7343-50. doi: 10.1039/c1ob05773a. Epub 2011 Sep 5.
In the present study, the synthesis and characterization of a series of N-methylimidazole-based thiourea and selenourea derivatives are described. The new compounds were also studied for their ability to inhibit peroxynitrite (PN)- and peroxidase-mediated nitration of protein tyrosine residues. It has been observed that the selenourea derivatives are more efficient than the thiourea-based compounds in the inhibition of protein nitration. The higher activity of selenoureas as compared to that of the corresponding thioureas can be ascribed to the zwitterionic nature of the selenourea moiety. Single crystal X-ray diffraction studies on some of the thiourea and selenourea derivatives reveal that the C=S bonds in thioureas possess more of double bond character than the C=Se bonds in the corresponding selenoureas. Therefore, the selenium compounds can react with PN or hydrogen peroxide much faster than their sulfur analogues. The reactions of thiourea and selenourea derivatives with PN or hydrogen peroxide produce the corresponding sulfinic or seleninic acid derivatives, which upon elimination of sulfurous/selenous acids produce the corresponding N-methylimdazole derivatives.
在本研究中，描述了一系列基于 N-甲基咪唑的硫脲和硒脲衍生物的合成和表征。还研究了新化合物抑制过氧亚硝酸盐 (PN) 和过氧化物酶介导的酪氨酸残基硝化的能力。观察到硒脲衍生物在抑制蛋白质硝化方面比基于硫脲的化合物更有效。与相应的硫脲相比，硒脲的更高活性可以归因于硒脲部分的两性离子性质。对一些硫脲和硒脲衍生物的单晶 X 射线衍射研究表明，硫脲中的 C=S 键比相应的硒脲中的 C=Se 键具有更多的双键性质。因此，硒化合物可以比其硫类似物更快地与 PN 或过氧化氢反应。硫脲和硒脲衍生物与 PN 或过氧化氢的反应生成相应的亚磺酸或硒酸衍生物，这些衍生物在消除亚硫酸/亚硒酸后生成相应的 N-甲基咪唑衍生物。
