Reactions for drug synthesis under cell-like conditions or even inside living cells can potentially be used , to minimize toxic side effects, to maximize bioactive compound efficacy and/or to address drug delivery problems. Those reactions should be bioorthogonal to enable the generation of drug-like compounds with sufficiently good yields. In the known bioorthogonal Michael reactions, using thiols and phosphines as nucleophiles (, in CS and CP bond formation reactions) is very common. No bioorthogonal Michael addition with a carbon nucleophile is known yet. Therefore, the development of such a reaction might be interesting for future drug discovery research. In this work, the metal-free Michael addition between cyclohexanone and various nitrostyrenes (CC bond formation reaction), catalysed by a dipeptide salt H-Pro-Phe-ONa, was investigated for the first time in the presence of glutathione (GSH) and in phosphate-buffered saline (PBS). We demonstrated that with electron-withdrawing substituents on the aromatic ring and in -position of the nitrostyrene yields up to 64% can be obtained under physiological conditions, indicating a potential bioorthogonality of the studied Michael reaction. In addition, the selected Michael products demonstrated activity against human ovarian cancer cells A2780. This study opens up a new vista for forming bioactive compounds via CC bond formation Michael reactions under physiological (cell-like) conditions.

中文翻译：

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生理条件下二肽催化的迈克尔反应：潜在生物正交性的检查

可以使用类细胞条件下甚至活细胞内的药物合成反应来最大限度地减少毒副作用，最大限度地提高生物活性化合物的功效和/或解决药物输送问题。这些反应应该是生物正交的，以便能够以足够好的产率生成类药物化合物。在已知的生物正交迈克尔反应中，使用硫醇和膦作为亲核试剂（在CS和CP键形成反应中）是非常常见的。目前还不知道与碳亲核试剂的生物正交迈克尔加成反应。因此，这种反应的发展可能对未来的药物发现研究很有趣。在这项工作中，首次研究了二肽盐 H-Pro-Phe-ONa 催化下环己酮和各种硝基苯乙烯之间的无金属迈克尔加成反应（CC 键形成反应）磷酸盐缓冲盐水 (PBS) 中。我们证明，在生理条件下，芳环上和硝基苯乙烯的同位上有吸电子取代基时，产率可达 64%，这表明所研究的迈克尔反应具有潜在的生物正交性。此外，所选的 Michael 产品还表现出针对人类卵巢癌细胞 A2780 的活性。这项研究开辟了在生理（细胞样）条件下通过 CC 键形成迈克尔反应形成生物活性化合物的新前景。