orthochlorophenyl

Ortho chlorophenyl, also known as 2‑chlorophenyl, is a substituted aromatic group consisting of a benzene ring bearing a chlorine atom at the position ortho to a point of attachment. Its molecular formula is C6H5Cl and the simplest precursor is chlorobenzene. In the orthochlorophenyl moiety the chlorine occupies the adjacent ring position relative to the substituent bond, which influences both electronic distribution and steric interactions in the parent molecule.

In synthetic chemistry the ortho‑chlorophenyl group is introduced primarily through electrophilic aromatic substitution of chlorobenzene, radical chlorination of phenyl derivatives, or palladium‑catalysed cross‑coupling reactions with 2‑chlorophenyl electrophiles. Because the electron‑withdrawing chlorine increases the electrophilicity of the ring, ortho‑chlorophenyl compounds are frequently used as intermediates in the manufacture of pesticides, dyes, and pharmaceutical agents. For example, several herbicides contain the ortho‑chlorophenyl scaffold and its derivatives are found in analgesic and anti‑inflammatory drugs as part of larger heterocyclic frameworks.

Physically, 2‑chlorophenyl groups contribute to moderate lipophilicity, reflected in a logP (octanol/water partition coefficient) in the range of 2.5–3.5 for simple salts. The presence of the chlorine weakens the aromatic C–H bond at the ortho position, aiding radical abstraction or nucleophilic attack in synthetic transformations. Chemically, ortho‑chlorophenyl compounds are stable under neutral conditions but can undergo nucleophilic aromatic substitution when strongly electron‐deficient substituents are present elsewhere on the ring.

Safety considerations for ortho‑chlorophenyl compounds align with general aromatic chlorides: they are toxic if inhaled or ingested, can irritate skin and mucous membranes, and may cause environmental persistence. Proper protective equipment, ventilation, and waste disposal procedures are recommended during handling.