Synthesis of polyhydroquinoline derivatives in the presence of [PVP-SO3H] HSO4 under solvent-free conditions

Quinolines have been identified as promising structure in medicinal chemistry because of their many pharmacological properties, including their antibacterial antihypertensive, anti‐inflammatory, antimalarial, antiasthmatic, and tyrosine kinase inhibitory activity. In recent years, a number of methods have been reported onhantzsch. Many of the hantzsch methods have disadvantages such as expensive reagents, formation of side products, thermal instability, and difficult accessibility to reagents. Thus, a mild, convenient, and high yield procedure using inexpensive catalyst would be valuable [1]. [PVP-SO3H] HSO4 is a solid acid catalyst, which improves the reaction in solvent-free conditions [2]. In this work, [PVP-SO3H] HSO4 was used as catalyst in the hantzsch synthesis of polyhydroquinoline derivatives via four component reaction ofaldehydes, ammonium acetate, diketone, and ethylacetoacetate. The procedure has several advantages such as shorter reaction time, higher purity and yields, high reaction rates, ease of preparation and handling of the catalyst, simple and green experimental procedure and use of inexpensive and reusable catalyst for five times without loss of its catalytic activity.