反应详情

A mixture of meso-2,3-bis-(4-chlorophenyl)-2,3-butanediamine (70 mg, 0.226 mmol, example 1) and triethylamine (62 uL, 0.226 mmol) in 2 mL of dichloromethane was reacted with 0.225 mmol of 4-(tert-butyl)-2-ethoxy-benzoyl chloride (prepared from the reaction of 0.225 mmol of 4-(tert-butyl)-2-ethoxy-benzoic acid and 0.34 mmol of oxalyl chloride) for 30 min at room temperature. The mixture was partitioned between 10% sodium bicarbonate solution and dichloromethane. The dichloromethane extract was washed with water, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to give the crude amide mixture. Purification by chromatography on silica gel, eluting with hexane-ethyl acetate (3:1) provided 20 mg of N-[2-amino-1,2-bis-(4-chloro-phenyl)-1-methyl-propyl]-4-(tert-butyl)-2-ethoxy-benzamide. The intermediate was refluxed under argon with 0.5 mg of toluenesulfonic acid monohydrate and 7 mL of toluene for 3.5 h, then cooled, taken up in ethyl acetate and washed successively with saturated sodium bicarbonate, water and brine. The ethyl acetate layer was dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. Purification by chromatography on silica gel, eluting with ethyl acetate, followed by ethyl acetate-methanol (95:5) provided 9.5 mg of rac-(4S*,5R*)-4,5-bis(4-chlorophenyl)-2-(4-(tert-butyl)-2-ethoxy-phenyl)-4,5-dimethyl-4,5-dihydro-1H-imidazole. LR-MS: 495.0 [(M+H)+]

1. customThe mixture was partitioned between 10% sodium bicarbonate solution and dichloromethane
2. extractionThe dichloromethane extract
3. washwas washed with water
4. dry with materialdried over anhydrous sodium sulfate
5. filtrationfiltered
6. concentrationconcentrated under reduced pressure
7. customto give the crude amide mixture
8. customPurification by chromatography on silica gel
9. washeluting with hexane-ethyl acetate (3:1)