Quinolin4ol

Quinolin-4-ol, also known as 4-hydroxyquinoline, is a heterocyclic aromatic compound consisting of a quinoline skeleton with a hydroxy group at the 4-position. The structure features a benzene ring fused to a pyridine ring, with the hydroxyl group providing a phenolic site for hydrogen bonding and metal coordination.

It is predominantly synthesized for research and industrial use; common preparation routes involve cyclization of suitably substituted precursors followed by oxidation to introduce the hydroxyl group. The compound and many of its derivatives serve as versatile building blocks in organic synthesis.

In coordination chemistry, deprotonated 4-hydroxyquinoline acts as a bidentate ligand, binding metal centers through the ring nitrogen and the phenolate oxygen. Derivatives are used to form fluorescent dyes, chelating agents, and ligands for transition and lanthanide metals. The 4-hydroxyquinoline framework also appears in medicinal chemistry as a scaffold for antimicrobial and anticancer agents, and in fluorescent probes and sensors where metal ions influence emission.

Physical properties: 4-hydroxyquinoline is a pale solid with limited water solubility but higher solubility in organic solvents; it can be sensitive to strong oxidizing conditions.

Safety: use standard laboratory precautions; avoid inhalation and contact with skin or eyes; consult safety data for toxicity and disposal information.

See also: 8-hydroxyquinoline, 2-hydroxyquinoline, hydroxyquinoline derivatives.