4-(4-Chlorophenyl)butan-2-one (CAS no.: ), which is known as , 4-(4-chlorophenyl)-, could be produced through the following synthetic route.

A 500-mL, four-necked, round-bottomed flask equipped with a magnetic stirring bar, a thermometer, a gas inlet, an externally cooled, pressure-equalizing dropping funnel, and a gas bubbler is charged with 15% aqueous titanium trichloride (92 mL, 0.109 mol). (70 mL) is added during 45 min with stirring and cooling (ice-bath; 0–5°C) while is bubbled through the solution. Freshly distilled 3-buten-2-one (5.7 mL, 0.066 mol) is added at 0–5°C by syringe. The nitrogen flow is stopped, and 4-chlorobenzenediazonium chloride solution (0.044 mol) is added dropwise at 0–5°C from the dropping funnel. After 2–3 min, nitrogen evolution commences, and the rate of addition is adjusted so that 1–2 bubbles per second are vented through the bubbler. Nitrogen evolution continues for 20 min after the addition is complete (1.5 hr). The ice bath is removed and the solution stirred for 1 hr at room temperature. Ether, 50 mL, is added with stirring, and the organic phase is separated. The aqueous phase is extracted with ether (3 × 50 mL) and the combined organic extracts are washed with 3% aqueous Na₂CO₃ (2 × 30 mL) and water, dried over magnesium sulfate, and concentrated under reduced pressure. The residue is distilled to give 5.2–6.0 g (65–75% yield) of 4-(4-chlorophenyl)butan-2-one as a pale-yellow liquid, bp 90–91°C (0.5 mm).