N,N,N',N'-Tetramethylethylenediamine → 4,4'-Didodecyl-2,2'-bithiophene

Participants

Reaction Steps

n-BuLi (7.04 mL, 2.5 M in hexanes) was added dropwise to a stirring solution of 3-dodecylthiophene (4.000 g, 15.8 mmol) and N,N,N′,N′-tetramethylethylenediamine (2.75 mL, 17.6 mmol) in 80.0 mL of dry ether at −78° C. The solution was then warmed to room temperature and refluxed for 1 hour. After the solution was cooled to −78° C., CuCl2 (2.640 g, 19.6 mmol) was added in one portion. The reaction mixture was stirred overnight, during which time the temperature rose to room temperature. The reaction mixture was quenched with water and the resulting mixture was extracted with chloroform. The combined organic layers were washed with water, dried over MgSO4 and filtered, and the filtrate was concentrated to dryness. The crude product was purified by column chromatography on silica gel with hexanes as the eluent to yield a mixture of 4,4′- and 3,3′-didodecylthiophene (˜15% of the mixture by 1H NMR). Recrystallization from an acetone:ethanol (1:1) mixture gave 4,4′-didodecyl-2,2′-bithiophene (25) as a white solid (2.200 g, 55% yield). 1H NMR (CDCl3): δ 0.91 (t, 6H), 1.33 (m, 36H), 1.66 (q, 4H), 2.60 (t, 4H), 6.80 (s, 2H), 7.01 (s, 2H) ppm.

Provenance & Evidence