2818-69-1Relevant articles and documents
Visible light initiated oxidative coupling of alcohols ando-phenylenediamines to synthesize benzimidazoles over MIL-101(Fe) promoted by plasmonic Au
Hao, Mingming,Li, Zhaohui,Qin, Yuhuan,Xu, Chao
, p. 4161 - 4169 (2021/06/17)
The use of visible light to initiate one-pot synergistic/cascade reactions is a green and energy saving strategy. In this manuscript, we report that MIL-101(Fe) can act as a multifunctional catalyst to realize the oxidative condensation betweeno-phenylenediamines and alcohols to synthesize benzimidazoles under visible light. The deposition of plasmonic Au nanoparticles (Au NPs) on MIL-101(Fe) led to significantly improved activity. Both controlled experiments and electron spin resonance (ESR) results revealed that the production of benzimidazoles fromo-phenylenediamines and alcohols involves three sequential steps,i.e., the oxidative dehydrogenation of alcohols to produce aldehydes, the condensation betweeno-phenylenediamines and the aldehydes to produce Schiff bases and their oxidation to form benzimidazoles,viaa superoxide radical (O2˙?)-mediated pathway. The promoting effect of plasmonic Au NPs in this reaction can be ascribed to the effective transfer of the surface plasmon resonance (SPR)-excited hot electrons to the lowest unoccupied molecular orbital (LUMO) of MIL-101(Fe), which led to the generation of more active O2˙?radicals. This study not only provides a green and sustainable way for the synthesis of benzimidazoles, but also highlights the great potential of using rationally designed plasmonic metal NP/MOF nanocomposites as multifunctional catalysts for light initiated one-pot tandem/cascade reactions.
Rhodium catalyzed 2-alkyl-benzimidazoles synthesis from benzene-1,2-diamines and tertiary alkylamines as alkylating agents
Yamini,Sharma, Saurabh,Das, Pralay
, (2021/05/17)
Substituted 2-alkyl-benzimidazoles were synthesized from benzene-1,2-diamine and tertiary amines as alkylating agent under polystyrene supported rhodium (Rh@PS) nanoparticles (NPs) catalyzed conditions. The heterogeneous rhodium catalyst was applied first time for the synthesis of 2-alkyl-benzimidazoles. The reaction followed through oxidation of alkylamines, transamination, and oxidative cyclisation with benzene-1,2-diamines for the corresponding products synthesis with good yields. The process is applicable for vast substrate scope, several functional groups are tolerable, and the Rh@PS catalyst is recyclable up to four cycles without significant loss in catalytic activity.
Simple inorganic base promoted C-N and C-C formation: synthesis of benzo[4,5]imidazo[1,2-a]pyridines as functional AIEgens used for detecting picric acid
Yang, Kai,Luo, Shi-He,Chen, Si-Hong,Cao, Xi-Ying,Zhou, Yong-Jun,Lin, Yan-Lan,Huo, Yan-Ping,Wang, Zhao-Yang
supporting information, p. 8133 - 8139 (2021/10/04)
Metal-free catalyzed intermolecular tandem Michael addition/cyclization has been developed for the synthesis of benzo[4,5]imidazo[1,2-a]pyridines from α-bromocinnamaldehyde and 2-substituted benzimidazoles. The reaction promoted by a simple inorganic base displays moderate to good yields and good functional group tolerance. The optical properties of some typical products have been investigated. We found that, due to the presence of the benzene ring at the C1-position of benzo[4,5]imidazo[1,2-a]pyridines which restricts intramolecular motion, as a new type of aggregation-induced emission (AIE) luminogen (AIEgen), they show very good solid-state fluorescence with quantum yields up to 88.80%. Importantly, the AIE performance of compound3bcan be useful to detect the nitroaromatic explosive picric acid (PA) with a detection limit and quenching constant of 42.5 nM and 7.27 × 104M?M, respectively.
