反应详情

Part A. To a solution of 4,5-diphenyl-1-[(trimethylsilyl)ethoxymethyl]-1H-imidazole (2.5 g, 0. 00734 mol) (B. Lipshutz, B. Huff, W. Hazen, Tetrahedron Letters, 29, 3411-14, 1988), in dry tetrahydrofuran (50 mL) cooled to -78° under a nitrogen atmosphere, n-butyl lithium in hexane (2.5M, 0.00734 mol) was added slowly. The reaction mixture was stirred for 1 hour and 1,6-dibromohexane (2.68 g, 0.0011 mol) was added rapidly, stirred for 1/2 hour and was allowed to warm to ambient temperature and stirred for 2 additional hours. The reaction mixture was poured into water and extracted with ethyl acetate (2×50 mL). The combined organic layer was washed with water, brine, dried over magnesium sulfate and concentrated to give a viscous oil. The product was purified by flash chromatography on silica gel (250 mL) eluting with hexane:ethyl acetate (70:30 v:v) to give 6-bromo-1-(4,5-diphenyl-1-[(trimethylsilyl)ethoxymethyl]imidazol-2-yl)hexane as an oil (2.18 g, 0.00424 mol). 1H NMR (CDCl3) δ 7.53-7.16(m,10H), 5.10(s,2H), 3.48(t,2H), 3.34(t,2H), 2.90(t,2H), 1.99-1.5 (m,8H), 0.875(t,2H), 0.008(s,9H).

1. stirringstirred for 1/2 hour
2. stirringstirred for 2 additional hours
3. extractionextracted with ethyl acetate (2×50 mL)
4. washThe combined organic layer was washed with water, brine
5. dry with materialdried over magnesium sulfate
6. concentrationconcentrated
7. customto give a viscous oil
8. customThe product was purified by flash chromatography on silica gel (250 mL)
9. washeluting with hexane:ethyl acetate (70:30 v:v)