Advances in the Synthesis of Ring-Fused Benzimidazoles and Imidazobenzimidazoles

Molecules

Darren Conboy¹  Martin Sweeney²  StylianaI. Mirallai²  Fawaz Aldabbagh² 

[1] Department of Pharmacy, School of Life Sciences, Pharmacy and Chemistry, Kingston University, Penrhyn Road, Kingston upon Thames KT1 2EE, UK;School of Chemistry, National University of Ireland Galway, University Road, H91 TK33 Galway, Ireland;

关键词: green chemistry;    halogen;    heterocycle;    hydrogen peroxide;    imidazole;    iodine;   

DOI  :  10.3390/molecules26092684

来源: DOAJ

【 摘 要 】

This review article provides a perspective on the synthesis of alicyclic and heterocyclic ring-fused benzimidazoles, imidazo[4,5-f]benzimidazoles, and imidazo[5,4-f]benzimidazoles. These heterocycles have a plethora of biological activities with the iminoquinone and quinone derivatives displaying potent bioreductive antitumor activity. Synthesis is categorized according to the cyclization reaction and mechanisms are detailed. Nitrobenzene reduction, cyclization of aryl amidines, lactams and isothiocyanates are described. Protocols include condensation, cross-dehydrogenative coupling with transition metal catalysis, annulation onto benzimidazole, often using CuI-catalysis, and radical cyclization with homolytic aromatic substitution. Many oxidative transformations are under metal-free conditions, including using thermal, photochemical, and electrochemical methods. Syntheses of diazole analogues of mitomycin C derivatives are described. Traditional oxidations of o-(cycloamino)anilines using peroxides in acid via the t-amino effect remain popular.

【 授权许可】

Unknown