Background: Benzimidazole and benzothiazole subunits exist in many biologically active
molecules, natural products, and synthetic compounds. These compounds have recently gained widespread
interest due to their key role in medically important compounds, such as those exhibiting anticancer
activity, antimicrobial activity, inhibition of hepatitis C virus NS5B polymerase, p38 kinase inhibitory
activity, and anti-inflammatory activity.
Methods: 2-Substituted benzimidazole and benzothiazole derivatives have been synthesized by the condensation
of 1,2-phenylenediamine or 2-aminobenzothiophenol with 5-arylidenepyrimidine-2,4,6-(1H,3H,
5H)-trione derivatives via cleavage of C-C double bond without using a catalyst in EtOH under reflux
Results: We report here a very simple, novel, efficient, and catalyst-free method for the synthesis of benzimidazole
and benzothiazole in good to excellent yields from the treatment of 1,2-phenylenediamine and
2-aminothiophenol with various 5-arylidenepyrimidine-2,4,6(1H,3H,5H)-trione, respectively. This reaction
proceeds via cleavage of a C=C double bond and elimination of barbituric acid.
Conclusion: This method appears to be general for the synthesis of benzimidazoles and benzothiazoles
using 5-arylidenepyrimidine-2,4,6-(1H,3H,5H)-trione derivatives containing various aromatic and heteroaromatic
aldehydes such as furfural and thiophene-2-carbaldehyde with electron-withdrawing and