4-(Methylthio)phenylacetic acid ethyl ester is an aromatic sulfur-containing ester that combines a lipophilic methylthio group with a phenyl-acetate skeleton. The compound is virtually odourless, air-stable, and miscible with common organic solvents (ethyl acetate, dichloromethane, methanol, ethanol) while being practically insoluble in water.
Key physical data:
Density: 1.11 g cm⁻³ (25 °C)
Refractive index n²⁰/D: 1.54
Flash point: 136 °C
Vapour pressure: 0.001 mmHg (25 °C)
Log P (predicted): 3.2
Typical uses:
Central intermediate for the selective COX-2 inhibitor etoricoxib: the methylthio group is oxidised to the corresponding methylsulfone before further hetero-cyclisation .
Precursor to triazole and imidazole derivatives with anti-inflammatory or analgesic activity.
Building block for UV-absorbers, liquid-crystalline materials and fluorescent probes that require a lipophilic phenyl-acetate handle.
Quality specification (commercial grade):
Purity (GC): ≥98 %
Water content (KF): ≤0.3 %
Free acid (as 4-methylthiophenylacetic acid): ≤0.5 %
Residue on ignition: ≤0.1 %
Heavy metals: ≤20 ppm
Hazard statement:
Causes skin and eye irritation (R36/37/38). Avoid inhalation of vapour; use gloves, goggles and adequate ventilation. SDS available on request.
