Substituted, Fused, Tricyclic 6,7‐Dihydro‐1H,5H‐pyrido[1,2,3‐de]quinoxaline‐3‐amines by Isocyanide‐Abetted Cycloaddition Reaction

Abstract

A new method for the synthesis of substituted, fused, tricyclic 6,7‐dihydro‐1H,5H‐pyrido[1,2,3‐de]quinoxaline‐3‐amine derivatives from aldehydes, isocyanides, and 1,2,3,4‐tetrahydroquinolin‐8‐amine in the presence of scandium(III) trifluoromethanesulfonate as the catalyst was developed. An inventive approach for the activation of the nitrilium ion with an in situ formed 4‐(dimethylamino)pyridine‐stabilized imine synthon was also explored to enhance the yield of the desired, fused, tricyclic systems.