4hydroxy3methoxyphenylacetic

4hydroxy3methoxybenzaldehyde, commonly known as vanillin, is an organic compound with the molecular formula C8H8O3. It is the primary component of the extract of the vanilla bean. Vanillin is a phenolic aldehyde, and its chemical structure consists of a benzene ring substituted with a hydroxyl group, a methoxy group, and an aldehyde group. The arrangement of these substituents at the 4, 3, and 1 positions respectively, gives rise to its name.

Pure vanillin is a white to pale yellow crystalline solid. It has a distinct, pleasant aroma and taste characteristic of vanilla. This aroma is widely used in perfumes, flavorings for food and beverages, and pharmaceuticals. While natural vanillin is extracted from vanilla pods, the vast majority of vanillin used commercially is synthesized. Common synthetic routes involve the use of guaiacol or lignin, a byproduct of the paper industry.

Vanillin is soluble in organic solvents such as ethanol and ether, and sparingly soluble in water. Its chemical reactivity is typical of aldehydes and phenols. It can undergo oxidation to vanillic acid and reduction to vanillyl alcohol. It also participates in electrophilic aromatic substitution reactions. Beyond its sensory applications, vanillin has been investigated for its antioxidant and antimicrobial properties, although these are generally considered secondary to its flavoring role. Its widespread use makes it one of the most important flavor compounds globally.