11H-isoindolo[2,1-a]benzimidazoles (Review)

Abstract

Data on methods for the synthesis of isoindolo[2,1-a]benzimidazole and its derivatives and their chemical characteristics are reviewed. Data from quantum-chemical calculations of certain structures are presented. Possible practical applications of the compounds are indicated.

On the peculiar reactivity of a C,N-annelated isoindole core

“…The intense IR stretching vibration bands of the nonequivalent ester and amide carbonyl groups of 3 were observed at 1722 cm −1 and 1667 cm −1 , respectively. The presence of 2 different methyl groups was confirmed by 1 H ( δ N CH3 = 3.33 ppm, δ OCH3 = 3.78 ppm) and 13 C (δ N CH3 = 32.8 ppm, δ OCH3 = 52.6 ppm) NMR spectroscopy. The amido-ester 3 formally results from concomitant oxidative opening of a ring of the pyrrole ring of 1 and N-,O-dimethylation.…”

Metal-free regioselective tandem synthesis of diversely substituted benzimidazo-fused polyheterocycles in aqueous medium

“…20d The benzoindolopyridine scaffolds have gained significant attention due to their wide range of biological activities such as anticancer, antibacterial and DNA binding properties. 24,25 After the successful synthesis of diversely substituted benzimidazo-fused benzofuropyridines, we expanded this methodology for the synthesis of benzimidazo-fused benzoindolo [3,2-c]pyridines 7a-l using functionally varied o-alkynylaldehyde substrates 5a-k with substituted o-phenylenediamines 2a-b using standard reaction conditions (Scheme 4).…”