4-Bromomethyl-1,2-Dihydroquinoline-2-One

4-(Bromomethyl)quinolin-2(1H)-one (also known as 4-bromomethyl-2-quinolinone, bromomethylquinolinone, or 4-bromomethylcarbostyril) is a nitrogen-containing heterocyclic derivative of 2(1H)-quinolinone (carbostyril) bearing a bromomethyl group at the 4-position. At room temperature it is an off-white to pale yellow crystalline powder with a melting point of 255–258 °C, a boiling point of approximately 391.8 °C (at 760 mmHg), and a density of approximately 1.542 g/cm³. It is a widely used quinolone-type pharmaceutical intermediate. The product is poorly soluble in water and soluble in polar organic solvents such as dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF). It is chemically stable under normal temperature and pressure and meets the requirements of both pharmaceutical-grade and reagent-grade use. The product is hygroscopic and mildly irritating; store it sealed, protected from light, in a cool, dry place.

Chemical Structure

Applications：In the pharmaceutical field, 4-(bromomethyl)quinolin-2(1H)-one is a key starting material for the synthesis of rebamipide (CAS 90098-04-7), a gastric mucosal protective agent. Condensation with reagents such as diethyl acetamidomalonate affords 2-amino-3-[2(1H)-quinolinon-4-yl]propionic acid, the core intermediate of rebamipide, which is then acylated to give the active pharmaceutical ingredient. It also serves as a versatile synthetic building block: its benzylic bromide can be converted into a variety of functional groups, including amino, alkoxy, mercapto, and cyano groups, for the preparation of other quinolone-based drug molecules and intermediates. In the agrochemical field, it can be used as a raw material for the synthesis of agrochemical intermediates such as insecticides and fungicides. In addition, the product can be used as a reference standard for chromatographic calibration in the determination of related impurities and content.