3-Chloro-4-(methylthio)phenylacetic acid is an aromatic sulfur-containing carboxylic acid bearing a chlorine atom meta to the —CH₂COOH side chain and a lipophilic methylthio group para to the same side chain. The compound is odourless to faintly sulfurous, air-stable, and readily soluble in common organic solvents (ethanol, methanol, ethyl acetate, dichloromethane) while only sparingly soluble in cold water.
Key physical data:
Melting point: 152–154 °C
Predicted b.p.: 402 °C (760 mmHg)
Density: 1.41 g cm⁻³ (predicted)
Predicted pKa (carboxylic): 4.0
Predicted log P: 3.1
Typical uses:
Key intermediate for the selective COX-2 inhibitor etoricoxib; the methylthio group is oxidised to the corresponding methylsulfone before further hetero-cyclisation.
Building block for triazole and imidazole derivatives with anti-inflammatory or analgesic activity.
Starting material for agro-chemicals, UV-absorbers and liquid-crystalline materials that require a lipophilic phenyl-acetic acid handle.
Quality specification (commercial grade):
Purity (HPLC): ≥97 %
Water content (KF): ≤0.3 %
Residue on ignition: ≤0.1 %
Heavy metals: ≤20 ppm
Hazard statement:
Causes skin and eye irritation (R36/37/38). Avoid inhalation of dust; use gloves, goggles and adequate ventilation. SDS available on request.
