Catalytic Synthesis of 1,2,4,5‐Tetrasubstituted 1H‐Imidazole Derivatives: State of the Art

Abstract

1,2,4,5-Tetrasubstituted-1H-imidazoles are a large family of heteroarene derivatives that are known to include natural products isolated from marine sponges and synthetic compounds possessing a broad range of biological and pharmacological properties. Consequently, a great deal of attention has been given to the synthesis of these heteroarenes and reviews covering some synthetic aspects of this topic have been published in recent years. However, none of these reviews provides a comprehensive overview of the several catalytic methods developed in the literature for the preparation of this important class of heteroarenes. This article review with 469 references, 63% of them being related to the period 2010-2017, aims to provide an updated critical picture of the catalytic processes reported in the literature up to the end of 2017 for the synthesis of 1,2,4,5-tetrasubstituted-1H-imidazoles illustrating these protocols and their characteristic features such as scope, efficiency, versatility, and limitations. The review also summarizes the mechanisms of the catalytic processes proposed for many of the reported processes.

An Updated Review on the Synthesis and Antibacterial Activity of Molecular Hybrids and Conjugates Bearing Imidazole Moiety

“…As regards the synthetic methodologies used in these studies, it is worth noting that multicomponent condensation reactions, a class of benign processes that are characterised by experimental simplicity and low cost, have frequently been used for the synthesis of a variety of hybrids and conjugates [9,93,97,145,164,166,[176][177][178]219,220,232,237], and that such processes [250][251][252][253] as well as several other condensation reactions have often been preferentially carried out using microwave (MW)-promoted reactions instead of conventional heating sources [254][255][256][257][258]. In fact, as often highlighted by the published data, the advantages of microwave-promoted reactions [93,144,166,177,219,232] include significant shorter reaction times, higher yields, and product purity when compared to conventional thermal methods.…”

“…On the other hand, classical Pd-catalysed Suzuki-type reactions have only been used for the preparation of imidazole-pyridine fluorophores 2PBI (336), 3PBI (337), TBPI (338), and MPBI (339) [203]. Instead, atom economic strategies involving Pd-catalysed regioselective direct (hetero)arylation reactions of heteroaromatics with (hetero)aryl halides or pseudohalides [9][10][11][12][13][14][15], which have been and are still frequently used in the chemistry of imidazole derivatives, as well as the van Leusen reaction based of tosylmethylisocyanides, which is one of the most appropriate strategies for the preparation of imidazole-based medicinal molecules [260], to the best of our knowledge, have never been used for the synthesis of hybrids and conjugates belonging to the classes of substances mentioned in this review.…”

“…In 2015, Gomha and coworkers [204] reported the synthesis of pyridines 350a-e and 351a-e containing imidazole moiety and bipyridine derivatives 352, 353, and 354 in good yields via one-pot multicomponent condensation reactions [9] and evaluated the in vitro antibacterial activities of these compounds against Gram-positive and Gram-negative bacteria.…”

“…This review, with 261 references, in which we testified our continuing interest in the synthesis and bioactivity of imidazole derivatives [8][9][10][11][12][13][14][15], aims to summarise and comment on the main results obtained from the end of 1900s until the end of February 2020 in studies conducted by numerous international research groups on the synthesis and evaluation of the antibacterial properties of imidazole-based molecular hybrids and conjugates in which their discrete functional elements are directly covalently linked or are connected through a linker or spacer. The review, in which significant attention was paid to summarise the strategies used to overcome the antibiotic resistance of pathogens whose infections are difficult to treat with conventional antibiotics, was organised in the following main sections: However, this review did not include the synthesis and evaluation of the bioactivity of molecular hybrids and conjugates in which imidazole moieties are fused with carbo-or hetero-cyclic subunits or contain only (un)functionalised acyclic groups.…”

Catalyst H-ZSM 5 in Amines addition on Carbonyl Compounds α, β-unsaturated catalyzed by H-ZSM 5

“…From these results [18], we carried out a series of amine addition on a,bunsaturated alkenes [19], active or not active in a dry medium catalyzed by zeolite H-ZSM-5 [20]. Table 1 shows the 1, 4 -addition of a series of amines on α,b-unsaturated alkenes, ate catalyzed by zeolite H-ZSM-5 [21], in dry medium and a temperature T= 25°C.…”