4-(Methylthio)acetophenone is an aromatic methyl ketone carrying a lipophilic methylthio group at the para-position of the acetophenone ring. The compound is a faint-odour, air-stable solid that is readily soluble in common organic solvents (dichloromethane, chloroform, ethyl acetate, methanol, ethanol) and only sparingly soluble in water.
Key physical data: m.p. 80–82 °C; b.p. ~305 °C / 760 mmHg; density 1.15 g cm⁻³; flash point >110 °C; UV λmax (EtOH) 262 nm (ε ≈ 1.4 × 10⁴ M⁻¹ cm⁻¹). The substance shows good thermal stability and can be stored indefinitely in amber glass at 2–8 °C under nitrogen.
Typical uses:
Central building block for the production of the non-steroidal anti-inflammatory drugs rofecoxib (Vioxx) and etoricoxib; the methylthio group is oxidised to the corresponding methylsulfone, which is subsequently brominated and cyclised to give the desired 5-aryl-3-phenyl-isoxazole core .
Starting material for the synthesis of chalcone-type COX-2/LOX dual inhibitors and PPAR-α/δ agonists such as elafibranor for NASH therapy .
Versatile intermediate for agro-chemicals, UV-absorbers and liquid-crystalline materials that require a lipophilic aromatic ketone handle.
Hazard statement: Causes skin and eye irritation; may cause respiratory irritation. Use gloves, goggles and a dust mask. SDS available on request.
