The present work describes the catalytic activity of copper oxide nanoparticles dispersed on titanium dioxide in water for one‐pot synthesis of a library of hydrazinyl‐thiazoles via a three‐component reaction of various aldehydes/ketones with thiosemicarbazide and different phenacyl bromides. The structure of the synthesized compound, (E)‐4‐(4‐bromophenyl)‐2‐(2‐(4‐methoxybenzylidene) hydrazinyl)thiazole is confirmed by single crystal X‐ray diffraction studies. The catalyst prepared by a molten‐salt method is characterized by X‐ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, energy dispersive X‐ray spectroscopy, X‐ray photoelectron spectroscopy, Auger electron spectroscopy and electron spin resonance spectroscopy. The noteworthy advantages of this method include its broad substrate scope, clean reaction profile, short reaction times and high yields at low catalyst loading. Further, the product does not require any chromatographic purification and the method has the potential for large‐scale applications in pharmaceutical industries. In addition, the developed catalyst can be recovered and reused for 5 times without significant loss of activity. Mechanistic studies suggest that the reaction begins with the activation of the carbonyl group of both aldehyde/ketone and phenacyl bromide by copper oxide nanoparticles supported on titanium dioxide in water. These studies reveal that the reaction proceeds via the formation of thiosemicarbazone intermediate.

中文翻译：

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分散在二氧化钛载体上的氧化铜纳米粒子催化水介导的三锅合成肼基噻唑的绿色催化过程

本工作描述了分散在水中的二氧化钛上的氧化铜纳米粒子的催化活性，用于通过各种醛/酮与硫代氨基脲和不同的苯甲酰溴的三组分反应来一锅合成肼基-噻唑库。合成化合物的结构，（E）-4-（4-溴苯基）-2-（2-（4-甲氧基亚苄基）肼基）噻唑已通过单晶X射线衍射研究确定。通过熔融盐法制备的催化剂的特征在于X射线衍射，场发射扫描电子显微镜，透射电子显微镜，能量色散X射线光谱，X射线光电子光谱，俄歇电子光谱和电子自旋共振光谱。该方法的显着优势包括其广泛的底物范围，清洁的反应曲线，较短的反应时间和在低催化剂负载下的高收率。此外，该产品不需要任何色谱纯化，该方法具有在制药工业中大规模应用的潜力。此外，所开发的催化剂可以回收并重复使用5次，而活性没有明显损失。机理研究表明，该反应始于负载在水中的二氧化钛上的氧化铜纳米颗粒对醛/酮和苯甲酰溴的羰基基团的活化。这些研究表明反应进行了通过形成硫半脲中间体。