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Lithium Hexamethyldisilazane Transformation of Transiently Protected 4-Aza/Benzimidazole Nitriles to Amidines and their Dimethyl Sulfoxide Mediated Imidazole Ring Formation

Author:
Abou-Elkhair, Reham A. I., Hassan, Abdalla E. A., Boykin, David W., Wilson, W. David
Source:
Organic letters 2016 v.18 no.18 pp. 4714-4717
ISSN:
1523-7052
Subject:
DNA, aldehydes, amidines, benzimidazole, chemical reactions, chemical structure, diamines, dimethyl sulfoxide, lithium, nitriles, pharmaceutical industry
Abstract:
Trimethylsilyl-transient protection successfully allowed the use of lithium hexamethyldisilazane to prepare benzimidazole (BI) and 4-azabenzimidazole (azaBI) amidines from nitriles in 58–88% yields. This strategy offers a much better choice to prepare BI/azaBI amidines than the lengthy, low-yielding Pinner reaction. Synthesis of aza/benzimidazole rings from aromatic diamines and aldehydes was affected in dimethyl sulfoxide in 10–15 min, while known procedures require long time and purification. These methods are important for the BI/azaBI-based drug industry and for developing specific DNA binders for expanded therapeutic applications.
Agid:
5791754