Electrophilically activated nitroalkanes in double annulation of [1,2,4]triazolo[4,3-a]quinolines and 1,3,4-oxadiazole rings

Nitroalkanes activated with polyphosphoric acid could serve as efficient electrophiles in reactions with amines and hydrazines, enabling various cascade transformations toward heterocyclic systems. This strategy was developed for an innovative synthetic protocol employing simultaneous or sequential annulation of two different heterocyclic cores, affording [1,2,4]triazolo[4,3-a]quinolines with 1,3,4-oxadiazole substituents. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.