C₉H₉BrO₂ as Building Block

3′-Methoxyphenacyl Bromide CAS 5000-65-7 is a specialized, light-sensitive α-bromo ketone​ primarily valued as a photoremovable protecting group reagent​ for carboxylic acids and as an alkylating agent. Its meta-methoxy substitution can slightly alter its photolytic and electronic properties compared to the parent phenacyl bromide. Handling requires strict precautions due to its lachrymatory nature and sensitivity to light and moisture. For researchers in chemical biology, organic synthesis, and photochemistry, it provides a classic and effective tool for light-controlled deprotection and molecular conjugation.