3-Bromothiophene → Di(3-thienyl)methanol

Participants

Reaction Steps

To cooled (-78° C.) THF (100 ml) was added under nitrogen, n-butyllithium (2.5M, 40 ml) to the above mixture was added N-methyl-N-methoxy-urethane (6.28 g, 0.047 mol) in 5 ml of THF over a 0.5 h period and the mixture was allowed to warm to room temperature. The mixture was quenched with saturated ammonium chloride solution and the aqueous layer was extracted with ether. The combined organic layer was dried over magnesium sulfate, concentrated in vacuo, and the oil residue was crystallized from methanol to afford 1.465 g (16%) of 1,1-di-(3-thienyl)-ketone, m.p. 78°-80° C. Alternatively, 1,1-di-(3-thienyl) ketene was prepared as follows: To 100 ml of THF cooled -78° C. under nitrogen was added 2.5M n-butyllithium (36 ml ), and 14.67 g (0.09 mol) of 3-bromthiophene was added and the resulting mixture was stirred for 30 min. To the above mixture was added 3-thiophenecarboxaldehyde (10 g, 0.089 mol) in 10 ml of THF and the mixture was stirred allowing it to reach room temperature. Saturated ammonium chloride solution was added to the reaction mixture, the aqueous layer was extracted with ether, and the combined organic layer was concentrated in vacuo to yield 17.26 g (98.9%) of 1,1-di(3-thienyl)-methanol, as an oil.

Provenance & Evidence