AbstractWe present here a joint experimental and computational study on the formation of benzothiazoles. Our investigation reveals a green protocol for accessing benzothiazoles from acyl chlorides using either water alongside a reducing agent as the reaction medium or in combination with stoichiometric amounts of a weak acid, instead of the harsh conditions and catalysts previously reported. Specifically, we show that a protic solvent, particularly water, enables the formation of 2‐substituted benzothiazoles from N‐acyl 1,2‐aminothiophenols already at room temperature, without the need for strong acids or metal catalysts. DFT Molecular Dynamics simulations coupled with advanced enhanced sampling techniques provide a clear understanding of the catalytic role of water. We demonstrate how bulk water – due to its extended network of hydrogen bonds and an efficient Grotthuss mechanism – provides a reaction path that strongly reduces the reaction barriers compared to aprotic environments, namely more than 80 kJ/mol for the first reaction step and 250 kJ/mol for the second. Finally, we discuss the influence of different aliphatic and aromatic substituents with varying electronic properties on chemical reactivity. Besides providing in‐depth mechanistic insights, we believe that our findings pave the way for a greener route toward an important class of bioactive molecules.
摘要 我们在此介绍关于苯并噻唑形成的实验和计算联合研究。我们的研究揭示了一种从酰基氯中获得苯并噻唑的绿色方案,该方案使用水和还原剂作为反应介质,或结合一定量的弱酸,而不是之前报道的苛刻条件和催化剂。具体来说,我们的研究表明,在室温条件下,使用原生溶剂(尤其是水)就能从 N-酰基 1,2-氨基噻吩醇生成 2-取代的苯并噻唑,而无需强酸或金属催化剂。DFT 分子动力学模拟与先进的增强采样技术相结合,使我们对水的催化作用有了清晰的认识。我们展示了与烷基环境相比,大体积水如何通过其扩展的氢键网络和高效的 Grotthuss 机制,提供了一条可大大降低反应壁垒的反应路径,即第一步反应的壁垒降低了 80 kJ/mol 以上,第二步反应的壁垒降低了 250 kJ/mol。最后,我们讨论了具有不同电子特性的不同脂肪族和芳香族取代基对化学反应性的影响。除了提供深入的机理见解外,我们相信我们的发现还为获得一类重要的生物活性分子铺平了道路。