Recyclable Acid–Base Bifunctional Core–Shell–Shell Nanosphere Catalyzed Synthesis of 5‐Aryl‐1H‐1, 2, 3‐triazoles through the "One‐Pot" Cyclization of Aldehydes, Nitromethane, and Sodium Azide. Issue 16 (30th June 2017)

• Record Type: Journal Article
• Authors: Liu, Lei; Ai, Yongjian; Li, Dong; Qi, Li; Zhou, Junjie; Tang, Zhike; Shao, Zixing; Liang, Qionglin; Sun, Hong‐Bin
• Is Part Of: ChemCatChem. Volume 9:Issue 16(2017)
• Page Start: 3131
• Page End: 3137
• Publication Date: 2017-06-30
• Subjects: bifunctional catalysts -- heterogeneous catalysis -- nanostructures -- nitrogen heterocycles -- multicomponent reactions; Catalysis -- Periodicals; 541.39505
• DOI: 10.1002/cctc.201700401
• Languages: English
• ISSNs: 1867-3880

Abstract

Abstract: A magnetically separable core–shell–shell nanosphere, Fe3 O4 @nSiO2 ‐SO3 H@MS‐NHCOCH3 (n=nonporous, MS=microporous SiO2 ), was fabricated as an acid–base collaborative catalyst for the three‐component cyclization of aromatic aldehydes, nitroalkane, and sodium azide to afford 1 H ‐1, 2, 3‐triazoles. The bifunctional heterogeneous catalyst showed high activity for this transformation and good chemoselectivity, and toxic HN3 was not released during the course of the reaction. A variety of aldehydes were transformed into the corresponding 5‐aryl‐1 H ‐1, 2, 3‐triazoles in up to 98 % yield. Furthermore, the catalyst could be recovered by using an external magnetic field and reused many times without any loss in activity. In contrast, a homogeneous catalyst system comprising ammonium acetate/acetic acid also worked in this three‐component cyclization to afford 1 H ‐1, 2, 3‐triazoles. Abstract : Tri, tri, tri again : Fe3 O4 @nSiO2 ‐SO3 H@MS‐NHCOCH3 (n=nonporous, MS=microporous SiO2 ) is an efficient, heterogeneous catalyst for the formation of 1 H ‐1, 2, 3‐triazoles from aromatic aldehydes, nitromethane, and sodium azide. Few byproducts are formed, and the reaction is safe to handle, as dangerous hydrazoic acid is not released. The catalyst can be reused up to 10 times without any loss in catalytic activity.