Phenylacetylene → 4-(Phenylethynyl)pyridine

Participants

Reaction Steps

A mixture of 4-bromopyridine hydrochloride (9.75 g, 50 mmol), phenylacetylene (11 ml, 10.2 g; 100 mmol), copper (I) iodide (50 mg) and bis(triphenylphosphino)palladium (II) chloride (200 mg) in dry triethylamine (60 ml) was stirred under reflux for 16 h, the cooled reaction mixture filtered, and the filtrate evaporated. The residual black oil was dissolved in ethyl acetate (100 ml) and washed with saturated aqueous sodium carbonate (2×50 ml) and HCl (1M, 4×25 ml). The acidic washings were extracted with ethyl acetate (2×25 ml) and then basified (5M NaOH). The resulting suspension was extracted with dichloromethane (4×25 ml), the combined organic layers washed with water (25 ml), dried (MgSO4), evaporated, and the residue chromatographed on silica gel, eluting with 7:3 ethyl acetate/60°-80° petrol to give the product as a buff solid (2.79 g, 31%).

Provenance & Evidence