N,N,N',N'-Tetramethylethylenediamine → 1-[4,5-bis(4-methoxyphenyl)-1-(alpha-ethoxyethyl)-1H-imidazol-2-yl]2,2,2-trifluoro-1-ethanone

Participants

Reaction Steps

To a stirred solution of 14.12 g (40 mmoles) 4,5-bis(4-methoxyphenyl)-1-(α-ethoxyethyl)imidazole and 4.64 g tetramethylethylenediamine in 100 ml of dry THF under an atmosphere of nitrogen and cooled at -78° was added dropwise 30 ml of 1.6 M n-butyl lithium solution. After stirring for 15 minutes, a solution of 5.7 g (40.1 mmoles) N,N-dimethyltrifluoroacetamide in 30 ml of dry THF was added dropwise. After the addition was complete, the reaction mixture was stirred for 1 hour, with continued cooling, and then 150 ml of a saturated aqueous sodium bicarbonate solution was added dropwise. The mixture was allowed to warm to room temperature. The THF was removed by evaporation under vacuo on a rotary evaporator. The organic components were then extracted with 400 ml of methylene chloride, washed with 100 ml of a saturated solution of sodium bicarbonate, followed by water, and the organic extract was dried over magnesium sulfate. The inorganic salts were removed by filtration, and the solvent was removed by evaporation. The residue was chromatographed on a column of 250 g silica gel, eluting with a solvent mixture consisting of 90 parts toluene and 10 parts ethyl acetate. The chromatographed product thus obtained was crystallized from methyl cyclohexane to give 9 g of 1-[ 4,5-bis(4-methoxyphenyl)-1-(α-ethoxyethyl)-1H-imidazol-2-yl]2,2,2-trifluoro-1-ethanone, m.p. 124°-126°. Infrared and NMR spectra were consistent with the assigned structure.

Provenance & Evidence