Solvent-free synthesis of polyhydroquinoline derivatives employing mesoporous vanadium ion doped titania nanoparticles as a robust heterogeneous catalyst via the Hantzsch reaction

Mesoporous vanadium ion doped titania nanoparticles (V-TiO2) were used as a reusable and robust heterogeneous catalyst for one-pot four component synthesis of polyhydroquinoline derivatives via the esteemed Hantzsch reaction using arylaldehyde, beta-ketoester, dimedone and ammonium acetate at 80 degrees C under solvent-free conditions as a multi-component synthesis. On the other hand, the catalytic activity of V-TiO2 was compared with undoped commercial titania nanocatalyst. This protocol was successfully pertinent to a wide range of structurally diverse arylaldehydes with beta-ketoester, dimedone and ammonium acetate to afford the corresponding polyhydroquinoline derivatives. Operational simplicity, short reaction time and satisfactory yields are the key features of this protocol. The catalyst could easily be recycled and reused without observable decrease in catalytic activity.