Quinoline derivatives are prevalent in a wide range of pharmacologically active synthetic and natural compounds. Quinolines have antiseptic, antipyretic, and antiperiodic properties and are used as antimalarials and for preparing other antimalarial drugs. The discovery of chloroquine, the most famous drug containing this scaffold, resulted in control and treatment of malaria for decades. Quinoline and its derivatives are widely used as biocides, fungicides, alkaloids, antibiotics, rubber chemicals, dyes and flavoring agents. Additional industrial applications include their use as corrosion inhibitors, preservatives, and as solvents for resins and terpenes, and in transition-metal complex catalysis for uniform polymerization and luminescence chemistry. They are also used in manufacturing food colorants, oil soluble dyes, pH indicators, pharmaceuticals and other organic compounds. Quinoline is a catabolite of tryptophan, a fundamental structure in some antihypertensive agents such as the peripheral vasodilators prazosin and doxazosin. The presence of a halogen allows these reagents to be used as substrates in various coupling reactions, including Suzuki-Miyaura cross-coupling reactions.
