methoxy

Methoxy refers to the methoxy functional group, -O-CH3, an alkoxy substituent derived from methanol. In organic chemistry, methoxy is used as a substituent name in compounds such as anisole, or methoxybenzene. The group is attached to carbon through the oxygen atom and is commonly abbreviated as OMe.

Methoxy groups are electron-donating by resonance and activate aromatic rings toward electrophilic substitution, especially at the ortho and para positions. They increase the polarity of molecules and can influence solubility, reactivity, and the H-bonding profile of a compound. In many contexts, the presence of methoxy groups can alter the chemical and physical properties of natural products and synthetic intermediates.

Occurrence and biosynthesis: Methoxyl groups are common in plant metabolites and in lignin, where methyltransferases install methoxy groups on phenolic precursors to yield guaiacyl and syringyl units. Methoxy substituents also appear in flavors and fragrances such as vanillin and anisaldehyde.

Preparation and reactions: The methoxy group is typically introduced by O-alkylation of phenols or alcohols using methylating agents such as methyl iodide or dimethyl sulfate in the presence of base. The simplest example is anisole, formed by methylation of phenol.

Applications and related terms: Methoxy-containing compounds are widely used as solvents, flavor and fragrance ingredients, and intermediates in organic synthesis. In protecting-group chemistry, methoxymethyl ethers (MOM ethers) are used to protect alcohols, illustrating the versatility of methoxy functionality.

Safety: Compounds bearing methoxy groups vary in hazard; standard solvent-handling precautions apply. Risks depend on the specific compound and its concentration, with attention to flammability and potential toxicity of the parent or metabolite.