An Efficient Synthesis of 2,4,5-Triaryl-1h-Imidazole Using Sno2/Sio2 Nanocomposite Catalyst

Abstract

SnO2/SiO2 catalyzed synthesis of 2,4,5-triarylimidazoles by the condensation of benzoin, aromatic aldehydes and ammonium acetate in presence of ethanol as solvent. The synthesis highlights a synthesis and use of SnO2/SiO2 nanocomposite heterogeneous catalyst and its reusability. The method is cost effective and ecofriendly. And use of ethanol as a solvent makes the method more green and efficient. The method has simple workup procedure and the products are obtained in good to moderate yields.

Synthesis of the 1,5‐Benzothiazepane Scaffold – Established Methods and New Developments

“… [19] One way to achieve this is by looking at alternative catalysts that can be re‐used (e. g., Co 3 O 4 nanosheets [45] or H‐Fer zeolites), [46] are non‐toxic and cheaper (e. g., saturated ammonium chloride solution in water [10] or mango juice), [47] can be used in one‐pot tandem reactions (e. g., nanocrystalline ZSM‐5) [48] or either do not require the use of any solvent, or can be used with water as the solvent (e. g., tetra‐ n ‐butylammonium fluoride (TBAF) [49] or Na 2 CO 3 /tetrahexylammonium chloride (THAC) in water). [47] Another way to pursue greener approaches is to employ a different solvent that can be recycled and that allows for mild reaction conditions, such as hexafluoropropan‐2‐ol [50] and polyethylene glycol in combination with ultrasound irradiation, [51] or a biodegradable and non‐toxic solvent, such as glycerol. [52] Lastly, ionic liquids can be considered as another green alternative as they can be re‐used, can reduce the reaction time and can help to reduce the need of harmful catalysts.…”

Synthesis of Imidazole-Based Molecules under Ultrasonic Irradiation Approaches

“…These ultrasonic-ass reactions offered 32 in great yields of 82~99% within 3~15 min. Devkate and his co-workers claimed an enthralling one-pot three-component tion that synthesizes 2,4,5-triaryl-1H-imidazole 19 via a novel approach, in 2017 (Sch 32) [75]. They utilized polyethylene glycol PEG-400 as an effective and recoverable lyst to promote the condensation of the benzil 18, aromatic aldehydes 15, and ammon acetate 16.…”

“…The yields risen significantly for most reactions (87~95% for the ultrasonic method and 67~75% the conventional method) and remarkably reduced the reaction time (8~15 min fo ultrasonic method and 53~80 min for the conventional method). Devkate and his co-workers claimed an enthralling one-pot three-component reaction that synthesizes 2,4,5-triaryl-1H-imidazole 19 via a novel approach, in 2017 (Scheme 32) [75]. They utilized polyethylene glycol PEG-400 as an effective and recoverable catalyst to promote the condensation of the benzil 18, aromatic aldehydes 15, and ammonium acetate 16.…”