Reductive cyclization of o-phenylenediamine with CO2 and BH3NH3 to synthesize 1H-benzoimidazole derivatives was written by Li, Xiao;Zhang, Junhua;Yang, Yue;Hong, Hailong;Han, Limin;Zhu, Ning. And the article was included in Journal of Organometallic Chemistry in 2021.Quality Control of 1-Methylbenzimidazole This article mentions the following:
A simple and green protocol was developed for the reductive cyclization of o-phenylenediamine with CO2 and BH3NH3 to yield 1H-benzimidazole. The desired 1H-benzimidazole derivatives were produced under mild conditions. Mechanism investigation indicated that the coordination of o-phenylenediamine with the boron atom of BH3NH3 promoted the transfer of the formyl group to form a stable intermediate, which facilitated the intramol. nucleophilic addition-elimination for the formation of target product. In this process, BH3NH3 served multifunctional roles, acting as a reducing agent and a formylation catalyst. In the experiment, the researchers used many compounds, for example, 1-Methylbenzimidazole (cas: 1632-83-3Quality Control of 1-Methylbenzimidazole).
1-Methylbenzimidazole (cas: 1632-83-3) belongs to imidazole derivatives. Many natural products, especially alkaloids, contain the imidazole ring. These imidazoles share the 1,3-C3N2 ring but feature varied substituents. Many drugs contain an imidazole ring, such as certain antifungal drugs, the nitroimidazole series of antibiotics, and the sedative midazolam.Quality Control of 1-Methylbenzimidazole
Referemce:
Imidazole – Wikipedia,
Imidazole | C3H4N2 – PubChem