Hydrochloric Acid → 1-Benzyl-2,4,5-tribromo-1H-imidazole

HRID 2252027Notes

Reaction equation

[Br:1][C:2]1[NH:3][C:4]([Br:8])=[C:5]([Br:7])[N:6]=1.C(=O)([O-])[O-].[Cs+].[Cs+].[CH2:15](Br)[C:16]1[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=1.Cl.O1CCOCC1>CN(C)C=O>[CH2:15]([N:3]1[C:4]([Br:8])=[C:5]([Br:7])[N:6]=[C:2]1[Br:1])[C:16]1[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=1

Participants

Conditions

Temperature: -20 °C

Procedure

Combine 2,4,5-tribromoimidazole (15.29 g, 0.050 mol), cesium carbonate (18.0 g, 0.055 mol), benzyl bromide (6.3 mL, 0.053 mol) and dimethylformamide (100 mL) and stir at 20° C. for 18 hours. Filter solids and concentrate under reduced pressure. Suspend in dichloromethane, filter through 2 cm pad silica gel and wash with dichloromethane (1 L). Concentrate filtrates under reduced pressure. Redissolve in dichloromethane (15 mL), add 4 M HCl in dioxane (12.5 mL, 0.050 mol), cool to −20° C. and filter solids. Concentrate filtrate, dissolve in ethyl ether, add 1 M HCl/ether (20 mL) and hexane (40 mL), cool −20° C. and filter. Combine solids and dry under reduced pressure to give 19.6 g (90%, 0.045 mol) of the title compound. MS(ES+): m/z=393.0 (M+H)+

Workup

filtrationFilter solids
concentrationconcentrate under reduced pressure
filtrationfilter through 2 cm pad silica gel
washwash with dichloromethane (1 L)
dissolutionRedissolve in dichloromethane (15 mL)
filtrationfilter solids
dissolutionConcentrate filtrate, dissolve in ethyl ether
additionadd 1 M HCl/ether (20 mL) and hexane (40 mL)
temperaturecool −20° C.
filtrationfilter
customCombine solids and dry under reduced pressure

Sources & evidence

ORD record: ord-1acb8fd15f7f4c0bbca31130f5b12329
Source dataset: uspto-grants-2008_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07320995B2

Reaction notes

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