Cu(I)-Catalyzed and Base-Promoted [5 + 2 + 1] Cascade Cyclization of 2-Nitrochalcones with Aliphatic Primary Amines to 5 H-Pyrimido[5,4- b]indole Frameworks

Qin Wu; Genrui Xu; Weiqiang Li; Juan Wan; Teng Liu; Chao Huang

doi:10.1021/acs.orglett.2c01289

Cu(I)-Catalyzed and Base-Promoted [5 + 2 + 1] Cascade Cyclization of 2-Nitrochalcones with Aliphatic Primary Amines to 5 H-Pyrimido[5,4- b]indole Frameworks

Org Lett. 2022 Jun 10;24(22):3950-3954. doi: 10.1021/acs.orglett.2c01289. Epub 2022 May 31.

Authors

Qin Wu¹, Genrui Xu¹, Weiqiang Li¹, Juan Wan¹, Teng Liu², Chao Huang¹

Affiliations

¹ National and Local Joint Engineering Research Center for Green Preparation Technology of Biobased Materials, School of Chemistry and Environment, Yunnan Minzu University, Kunming 650500, P. R. China.
² College of Chemistry and Environmental Science, Qujing Normal University, Qujing 655011, P. R. China.

PMID: 35639963
DOI: 10.1021/acs.orglett.2c01289

Abstract

An unprecedented [5 + 2 + 1] cascade cyclization to the preparation of 5H-pyrimido[5,4-b]indole derivatives has been disclosed. The novel protocol of 2-nitrochalcones reacted with aliphatic primary amines catalyzed by CuI and promoted by Cs₂CO₃, which underwent a critical intermediate 2,3-disubstituted indole, providing structurally diverse 5H-pyrimido[5,4-b]indoles in generally high yields (77-90%) and broad substrate scopes (34 examples).