Synthesis of fused triazolo-imidazole derivatives by sequential van Leusen/alkyne–azide cycloaddition reactions

Parallel synthesis of arrays of 1,4,5-trisubstituted 1-(4-piperidyl)-imidazoles by IMCR: A novel class of aspartyl protease inhibitors

“…16 Many unprotected functional groups in the starting materials are compatible with the reaction conditions, including carboxylic acid, ketone, aldehyde, alcohol, amine, azide and alkyne moieties, and can thus provide valuable functionalized intermediates. Moreover, several subsequent reactions following the vL-3CR have been described giving access to even more diverse products, including triazolo-imidazoles by azide-alkyne cycloaddition 17 , imidazo azepine by enyne metathesis 18 , imidazo-pyridine and -azepine by Heck reaction 19 and other fused imidazoles.…”

Facile One-Pot Assembly of Imidazotriazolobenzodiazepines via Indium(III)-Catalyzed Multicomponent Reactions

“…Martin 5a,b and coworkers reported an effective route to 1,2,3-triazole-fused 1,4-benzodiazepines ( 4 ) via cascade reductive amination and intramolecular Huisgen cycloaddition reactions 5c (Scheme 1). In addition, the atom economy, ease of diversification, and operational simplicity of multicomponent reactions (MCRs) have been extensively exploited to provide ready accesses to these complex annulated ring systems from simple building blocks.…”

“…In addition, the atom economy, ease of diversification, and operational simplicity of multicomponent reactions (MCRs) have been extensively exploited to provide ready accesses to these complex annulated ring systems from simple building blocks. In that context, Van der Eycken has reported an expedient post-Ugi intramolecular heteroannulation approach for the synthesis of imidazo[1,4]diazepin-7-ones ( 5 ; Scheme 1) 5d,e and Djuric has demonstrated an interesting post-modification of the van Leusen imidazole synthesis using an intramolecular azide-alkyne cycloaddition to construct 6 , which incorporates imidazole, triazole, and diazepine rings in one scaffold. 5f …”

“…We envisioned that the resulting post-cyclocondensation system would preorganize the azide and alkyne moieties for a subsequent thermally-driven intramolecular 1,3-dipolar cycloaddition. 5a,8 The result of this one-pot, tandem, multicomponent reaction would be the tetracyclic core of 10 adorned with three diversification points (Scheme 2). 9 …”

An Efficient One‐Pot, Four‐Component Synthesis of {[(1H‐1,2,3‐Triazol‐4‐yl)methoxy]phenyl}‐1H‐pyrazolo[1,2‐b]phthalazine‐5,10‐dione Derivatives

“…The idea to use a MCR followed by a Huisgen copper catalyzed [3 þ 2] reaction was first presented by Ramachary and Barbas [16]. Recently, a number of medicinally relevant heterocycles were synthesized via MCRs combined with a click reaction, such as: sequential Ugi/intermolecular alkyneÀazide cycloaddition (IAAC) [17], sequential Van-Leusen/alkyneÀazide cycloaddition reactions [18], and the synthesis of triazolyl-substituted dihydropyrimidinone derivatives under microwave irradiation combining a Biginelli reaction with a Cu-catalyzed azideÀalkyne cycloaddition (CuAAC) in separate steps [19]. However, examples of one-pot multicomponent click reactions with four or more components are scarce [16] [20].…”