CH3OC6H4NH2

CH3OC6H4NH2 is an aromatic amine with the molecular formula C7H9NO2. It is commonly known as anisidine, the methoxy‑substituted derivative of aniline. The compound contains a benzene ring bearing both a methoxy group (–OCH3) and an amino group (–NH2). Because of the possible positions of these substituents on the ring, there are three isomeric forms: 2‑anisidine (o‑anisidine), 3‑anisidine (m‑anisidine) and 4‑anisidine (p‑anisidine). The most frequently used isomer in industrial applications is 4‑anisidine, which has a para relationship between the methoxy and amino groups.

The physical properties of 4‑anisidine include a pale yellow to brown liquid appearance, a boiling point around 255 °C, and a melting point of approximately –73 °C. It is soluble in water, ethanol, and most organic solvents. The amino group imparts basicity (pKa ≈ 5.2) and the methoxy group confers moderate electron‑donating character, influencing the compound’s reactivity.

Synthesis is typically achieved via nitration of anisole followed by reduction of the nitro group. Alternative routes include Friedel–Crafts alkylation of aniline with methyl chloride in the presence of a Lewis acid, which introduces the methoxy group. Commercial production often employs catalytic hydrogenation of 4‑nitroanisole using palladium‑on‑carbon or iron‑based catalysts.

Anisidine is used mainly as an intermediate in the manufacture of dyes, pigments, and pharmaceuticals. It serves as a building block for the synthesis of dyes such as 4‑chloroaniline derivatives, and it is also used in the preparation of herbicides and fragrances. Due to its aromatic amine structure, anisidine is subject to environmental and health regulations; it is moderately toxic and classified as a hazardous substance under regulatory frameworks such as REACH.