Fullerotetrahydroquinolines: TfOH/TsOH . H2O-Mediated One-Pot Two-Step Synthesis and N-Alkylation/Acylation/Carboamidation Reaction

A series of N-unsubstituted/substituted fullerotetrahydroquinolines without a directly attached nitrogen atom were synthesized in moderate to good yields via a one-pot two-step reaction of [60]fullerene with arylamines and paraformaldehyde in the presence of trifluoromethanesulfonic acid and p-toluenesulfonic acid monohydrate. Aromatic primary amines produce N-unsubstituted fullereotetrahydroquinolines, while aromatic secondary amines give N-substituted fullereotetrahydroquinoline derivatives. As precursors, N-unsubstituted fullerotetrahydroquinolines could be further derivatized by the N-alkylation/acylation/carboamidation reactions to produce a large variety of N-substituted fullerotetrahydroquinolines containing Cl, NO2, C(O), and C(O)NH functional groups, which may have applications in the field of perovskite-based solar cells. Plausible reaction pathways for the formation of N-unsubstituted/substituted fullerotetrahydroquinolines were suggested to elucidate the above-mentioned reaction process.