Dihydrobenzimidazoles, Benzimidazolones, Benzimidazolethiones, and Related Compounds

ChemInform Abstract: Reactions of 3‐Substituted Chromones with ortho‐Phenylenediamine.

“…Despite this susceptibility to C-2 attack and the resulting easy opening of the heterocyclic ring, we attempted to reduce the C-C double bond in chromones in order to produce chromanones. This is in line with previous studies in which benzimidazolines generated in situ from 1,2-phenylendiamine and arylaldehyde [7] were successfully used as chemoselective reducing agents of exo- [8] or endo-cyclic [9] C-C double bonds. These attempts failed, however, probably because these systems do not incorporate a styrenic double bond, while complex sequences of conjugative additions were observed with the starting 1,2-diamine alone [10].…”

Rearrangement Strategy for the Synthesis of 2-Aminoanilines

“…For example, Nexium, Zyprexa, and Alphagan P (Figure ), which contain this group, had combined worldwide sales in excess of $6.5 billion in 2008 . Due to the fact that the structure serves as a precursor to a number of pharmacophores including benzimidazoles, 1,5-benzodiazepines, quinoxalines, benzotriazoles, and benzimidazolones, among others, simple methods for the selective introduction of this group have great synthetic potential.…”