Synthesis of heteroaryl ketones via tandem reaction of 1,1-dibromoethenes

A new synthetic pathway to four substituted imidazoles from readily available 2-((4-aryl(thienyl)-5H-1,2,3-dithiazol-5-ylidene)amino)phenols has been developed. Benzo[d]oxazol-2-yl(aryl(thienyl))methanimines were proved as key intermediates in their synthesis. The formation of an imidazole ring from two methanimine derivatives likely includes the opening of one benzoxazole ring followed by ring closure by intermolecular nucleophilic attack of the N-methanimine atom to a carbon atom of another methanimine.

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“…140–142 °C) [ 37 ]. The 1 H and 13 C NMR spectra were similar to those described in the literature [ 46 ].…”

Section: Methodssupporting

confidence: 75%

Synthesis of 2-((2-(Benzo[d]oxazol-2-yl)-2H-imidazol-4-yl)amino)-phenols from 2-((5H-1,2,3-Dithiazol-5-ylidene)amino)phenols through Unprecedented Formation of Imidazole Ring from Two Methanimino Groups

et al. 2020

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“…A variety of synthetic approaches to α‐keto (hetero)aryl benzoxazoles are based on the reaction of 1,1‐dibromoethenes, α,α‐dihaloketones, and alkynylbromides with 2‐aminophenols. The preparation of α‐keto (hetero)aryl benzoxazoles 10 or 29 was through the coupling reaction of 1,1‐dibromoethenes 40 with o ‐aminophenols 42 under the assistance of TBAF·3H 2 O and RuCl 3 complex.…”

Section: Synthesis Of 2‐keto‐annulated Oxazolesmentioning

confidence: 99%

“…The preparation of α‐keto (hetero)aryl benzoxazoles 10 or 29 was through the coupling reaction of 1,1‐dibromoethenes 40 with o ‐aminophenols 42 under the assistance of TBAF·3H 2 O and RuCl 3 complex. During the formation of compound 10 or 29 , the 1‐(2‐bromoethynyl)benzenes 41 is generated through the tetra ‐ n ‐butylammonium fluoride (TBAF)‐promoted dehydrobromination of 1‐(2,2‐dibromovinyl)benzene 40 , which acts as a crucial intermediate (Scheme ).…”

Section: Synthesis Of 2‐keto‐annulated Oxazolesmentioning

confidence: 99%

Overview on Recent Approaches towards Synthesis of 2‐Keto‐annulated Oxazole Derivatives

Aljaar

Gujjarappa

Al-Refai

et al. 2019

Journal of Heterocyclic Chem

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In recent years, oxazole derivatives have emerged as one of the formidable groups of compounds in the field of medicinal chemistry and drug discovery. The titled compounds 2‐keto‐annulated oxazoles play an important role towards the medicinal aspects. There has been an appearance of a significant number of research articles and reviews to explore the wide utility of oxazole derivatives. However, till now, there has been no dedicated review published focusing on the synthesis of 2‐keto‐annulated oxazole derivatives. Herein, we have presented the recent protocols available in literature for the synthesis of 2‐keto‐annulated oxazoles and highlighted the advantages of these methods that would attract the attention of a broad range of readers in the chemistry community.

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“…Therefore, developing new selective procedures to oxidize C−H bonds under an aerobic atmosphere are particularly desirable . Accordingly, both metal‐free systems and transition metal complexes have been well‐established to be active catalysts in this process.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of α,β‐Dicarbonylhydrazones by Aerobic Manganese‐Catalysed Oxidation

et al. 2018

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A practical, simple, and efficient manganese-catalysed oxidation of C(sp 2 )ÀH bond in readily available b-carbonylenehydrazine under aerobic conditions has been developed. This protocol exhibits a wide range of functional group tolerance in b-carbonylenehydrazines to afford a,b-dicarbonylhydrazones. Experimental and theoretical results suggest that the reaction very likely proceeds through a radical pathway via a hydrogen-atom-transfer process promoted by a Mn III species.[ a] Reaction conditions: catalyst: Mn(OAc) 2 · 4H 2 O (0.0125 mmol), b-keto-enehydrazine (0.5 mmol), solvent: EtOH (10 mL), oxidant: O 2 (1 atm), t = 18 h, T = 60 8C. [b] Isolated yield. [c] Yield determined by NMR.

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Synthesis of heteroaryl ketones via tandem reaction of 1,1-dibromoethenes

Cited by 41 publications

References 40 publications

Synthesis of 2-((2-(Benzo[d]oxazol-2-yl)-2H-imidazol-4-yl)amino)-phenols from 2-((5H-1,2,3-Dithiazol-5-ylidene)amino)phenols through Unprecedented Formation of Imidazole Ring from Two Methanimino Groups

Synthesis of 2-((2-(Benzo[d]oxazol-2-yl)-2H-imidazol-4-yl)amino)-phenols from 2-((5H-1,2,3-Dithiazol-5-ylidene)amino)phenols through Unprecedented Formation of Imidazole Ring from Two Methanimino Groups

Overview on Recent Approaches towards Synthesis of 2‐Keto‐annulated Oxazole Derivatives

Synthesis of α,β‐Dicarbonylhydrazones by Aerobic Manganese‐Catalysed Oxidation

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