反应详情

Add tert-butyl 4-(1H-imidazol-2-yl)piperidine-1-carboxylate (6.00 g, 23.87 mmol) in dichloroethane (200 mL). Add N-chlorosuccinimide (3.19 g, 1.0 eq). Stir at room temperature under nitrogen for 14 hours. Concentrate the reaction mixture in vacuo. Purify by silica gel chromatography, eluting with hexanes to 9:1 hexanes:ethyl acetate to 4:1 hexanes:ethyl acetate to 2:1 hexanes:ethyl acetate to 1:1 hexanes:ethyl acetate, to give two major spots. Concentrate fractions containing the higher Rf spot in vacuo to give tert-butyl 4-(4,5-dichloro-1H-imidazol-2-yl)piperidine-1-carboxylate (2.25 g, 29%). MS (ES) m/z=321 [M]+. Concentrate fractions containing the lower spot in vacuo. Slurry the resulting solid into diethyl ether/chloroform, then filter. Concentrate the filtrate in vacuo to give tert-butyl 4-(4-chloro-1H-imidazol-2-yl)piperidine-1-carboxylate (1.16 g, 17%). MS (ES) m/z=286 [M]+.

1. concentrationConcentrate the reaction mixture in vacuo
2. customPurify by silica gel chromatography
3. washeluting with hexanes to 9:1 hexanes
4. customethyl acetate to 4:1 hexanes:ethyl acetate to 2:1 hexanes:ethyl acetate to 1:1 hexanes:ethyl acetate, to give two major spots
5. additionConcentrate fractions containing the higher Rf spot in vacuo