Synthesis of benzo[ d]imidazo[2,1- b]benzoselenoazoles: Cs2CO3-mediated cyclization of 1-(2-bromoaryl)benzimidazoles with selenium

Mio Matsumura; Yuki Kitamura; Arisa Yamauchi; Yoshitaka Kanazawa; Yuki Murata; Tadashi Hyodo; Kentaro Yamaguchi; Shuji Yasuike

doi:10.3762/bjoc.15.199

Synthesis of benzo[ d]imidazo[2,1- b]benzoselenoazoles: Cs₂CO₃-mediated cyclization of 1-(2-bromoaryl)benzimidazoles with selenium

Beilstein J Org Chem. 2019 Aug 26:15:2029-2035. doi: 10.3762/bjoc.15.199. eCollection 2019.

Authors

Mio Matsumura¹, Yuki Kitamura¹, Arisa Yamauchi¹, Yoshitaka Kanazawa¹, Yuki Murata¹, Tadashi Hyodo², Kentaro Yamaguchi², Shuji Yasuike¹

Affiliations

¹ School of Pharmaceutical Sciences, Aichi Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya 464-8650, Japan.
² Pharmaceutical Sciences at Kagawa Campus, Tokushima Bunri University, 1314-1 Shido, Sanuki, Kagawa 769-2193, Japan.

Abstract

The synthesis of benzimidazo[2,1-b]benzoselenoazoles is described. The novel ring-closure reaction of 1-(2-bromoaryl)benzimidazoles with Se powder is promoted by Cs₂CO₃ (2 equiv) in DMF at 150 °C. Moreover, the obtained tetracyclic heterocycles are all novel compounds. Single-crystal X-ray analysis of the parent benzimidazo[2,1-b]benzoselenoazole revealed that the tetracyclic ring is almost planar. Absorption spectroscopy data of the benzimidazo[2,1-b]benzoselenoazoles showed the λ_max was dependent on the number of rings.

Keywords: benzimidazole; cesium carbonate; cyclization; selenium; selenoazole.