Sulfuric Acid → 1,4-Diphenyl-1,3-butadiyne

Participants

Reaction Steps

To a 50 ml round bottom flask equipped with a magnetic stirrer and reflux condenser was added 300 mg 4-decyloxy-3-fluorophenylacetylene and 43 mg cupric acetate in 40 ml 1:1 pyridine/MeOH. The reaction mixture was refluxed for 2 hrs, allowed to cool to room temperature and then added dropwise into a stirred 9M aqueous sulfuric acid solution at ice bath temperature. The resulting cream-like suspension was extracted with ethyl ether and sequentially washed with water (3×) and brine and dried with anhydrous magnesium sulfate yielding 289 mg of a yellow-brown solid. Flash chromatography (1% ethyl acetate/hexane) and recrystallization of the residue from 95% ethanol afforded 248 mg diphenyldiacetylene (5), 4,4'-didecyloxy-3,3'-difluoro diphenyldiacetylene, as pale yellow needles.

Provenance & Evidence