Cu(I)-Catalyzed and Base-Promoted [5 + 2 + 1] Cascade Cyclization of 2-Nitrochalcones with Aliphatic Primary Amines to 5<i>H</i>-Pyrimido[5,4-<i>b</i>]indole Frameworks
Qin Wu, Genrui Xu, Weiqiang Li, Juan Wan, Teng Liu, Chao Huang
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).
Topics & Concepts
ChemistryIndole testCatalysisCascadeSubstrate (aquarium)Base (topology)Primary (astronomy)Combinatorial chemistryStereochemistryMedicinal chemistryOrganic chemistryMathematical analysisChromatographyMathematicsAstronomyPhysicsGeologyOceanographySynthesis and Biological EvaluationCatalytic C–H Functionalization MethodsPhenothiazines and Benzothiazines Synthesis and Activities