An imine condensation/1,5-electrocyclization cascade enabled permanent aldehyde–amine coupling through a triazole linkage

Abstract

The condensation–rearrangement coupling reaction of primary amines and pyridotriazole carbaldehydes is investigated to reveal its value in organic synthesis. Both alkyl and aryl amines react rapidly and cleanly with various pyridotriazoles under mild conditions, and a broad scope of functional groups (OH, CO₂H, esters, halogens, etc.) is tolerated. Primary and secondary α-alkyl amines show comparable reactivity, but steric tertiary α-carbon markedly lowers their efficiency. The electronic nature of aryl amines influences the reaction rates: electron-rich and neutral aryl amines reach completion in ∼0.5 h, moderately electron-deficient ones in ∼1 h, and strongly electron-deficient ones need higher temperature, extended time, or both for full conversion.