反应详情

Part D. To a solution of N'-(2,4-difluorophenyl) -N-heptyl-N-5-hydroxypentylurea (15.0 g, 0.042 mol) and carbon tetrabromide (16.75 g, 0.051 mol) in methylene chloride (350 mL) under a nitrogen atmosphere at ambient temperature, a solution of triphenylphosphine (13.24 g, 0.051 mol) in methylene chloride (100 mL) was added slowly. The reaction mixture was stirred for 3 hours and then concentrated in vacuo to give crude viscous oil. The product was purified by flash chromatography on silica gel (400 mL) eluting with hexane:ethyl acetate (90:10::v:v) to give N-(5-bromopentyl)-N'-(2,4-difluorophenyl)-N-heptylurea as a viscous colorless oil (17.5 g, 0.042 mol). 1H NMR (CDCl3) δ8.14-8.00 (m, 1H), 6.92-6.79 (m, 2H), 6.35 (bs, 1H), 3.49-3.25 (m, 6H), 1.99-1.26 (m, 16H), 0.92 (t,3H, J=6.7 Hz).

1. concentrationconcentrated in vacuo
2. customto give crude viscous oil
3. customThe product was purified by flash chromatography on silica gel (400 mL)
4. washeluting with hexane:ethyl acetate (90:10::v:v)