Present paper elicits the multicomponent reaction (MCR) strategy assisted by titania nanoparticles hosted on silica (TiO₂.SiO₂ NPs) as heterogeneous catalyst to synthesize a series of pharmacologically significant 2,3‐diaryl‐3,4‐dihydroimidazo[4,5‐b]indole derivatives. To the best of our information, the use of isatin as one of the precursors was hitherto unreported. The decrease in reaction time, low catalyst loading, high product yield (up to 92%), and excellent reusability of the catalyst (up to 7 cycles) put this protocol under the umbrella of green chemistry tenets. Characterization of catalysts was achieved through a number of techniques viz., energy‐dispersive X‐ray (EDX) spectroscopy, field emission scanning electron microscopy (FESEM), powder X‐ray diffraction (XRD), fourier transform infrared (FTIR) spectra of adsorbed pyridine, temperature‐programmed desorption of ammonia, and porosity measurements by nitrogen adsorption (Brunauer–Emmett–Teller [BET] method). Also, the structures of synthesized compounds were corroborated on the basis of FTIR, nuclear magnetic resonance (NMR), mass, and elemental analyses data.

中文翻译：

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二氧化钛-二氧化硅纳米粒子集合体协助合成具有药理学意义的2,3-二芳基-3,4-二氢咪唑并[4,5-b]吲哚支架的非均相催化策略

本文提出了多组分反应（MCR）策略，该方法以二氧化硅（TiO ₂ .SiO ₂ NPs）为载体的二氧化钛纳米颗粒作为多相催化剂，合成了一系列具有重要药理意义的2,3-二芳基-3,4-二氢咪唑[4,5] ‐ b ]吲哚衍生物。据我们所知，迄今尚未报道使用伊斯丁作为前体之一。反应时间的减少，催化剂的低载量，高产品收率（高达92％）和出色的催化剂可重复使用性（高达7个循环）使该方案成为绿色化学原理的保护伞。催化剂的表征是通过多种技术实现的。，能量色散X射线（EDX）光谱，场发射扫描电子显微镜（FESEM），粉末X射线衍射（XRD），吸附吡啶的傅里叶变换红外（FTIR）光谱，程序升温的氨解吸和孔隙率通过氮吸附进行测量（Brunauer–Emmett–Teller [BET]方法）。此外，根据FTIR，核磁共振（NMR），质量和元素分析数据，证实了合成化合物的结构。