Hydrochloric Acid → 4-Ethynyl-4'-pentyl-1,1'-biphenyl

Participants

Reaction Conditions

Reaction Steps

A mixture of 4-bromo-4′-pentylbiphenyl (5.04 g), trimethylsilyacetylene (2.4 ml), tetrakis(triphenylphosphine)palladium (0.96 g), triphenylphosphine (0.22 g) and cuprous iodide (95 mg) in piperidine (10 ml) was heated for an hour under atmospheric pressure of nitrogen at 90° C. The reaction mixture was poured into a mixture of cold water and ethyl acetate, and adjusted to about pH 1 with 6N hydrochloric acid. The separated organic layer was washed with water and brine, and dried over magnesium sulfate. The magnesium sulfate was filtered of, and the filtrate was evaporated under reduced pressure to give crude 2-[4-(4-pentylphenyl)phenyl]-1-trimethylsilylacetylene, which was used for the next reaction without further purification. Crude mixture was dissolved in a mixture of dichloromethane (10 ml) and methanol (10 ml), and to the solution was added potassium carbonate (2.75 g) at 0° C. The mixture was allowed to warm to ambient temperature, and stirred for another 2 hours. The reaction mixture was poured into a mixture of cold water and ethyl acetate, and the resultant precipitate was filtered off. The filtrate was adjusted to about pH 7 with 1N hydrochloric acid, and washed with brine, and dried over magnesium sulfate. The magnesium sulfate was filtered off, and the filtrate was evaporated under reduced pressure to give a crude powder, which was subjected to column chromatography on silica gel (300 ml), and eluted with a mixture of (n-hexane:ethyl acetate=99:1-97:3, V/V) to give 4-(4-Pentylphenyl)phenylacetylene (2.09 g).

Provenance & Evidence