4-Bromobenzene-1,2-diamine → 2-(6-bromo-1H-benzimidazol-2-yl)pyrrolidine-1-carboxylic acid tert-butyl ester

HRID 71767

Reaction equation

[Br:1][C:2]1[CH:3]=[C:4]([NH2:9])[C:5]([NH2:8])=[CH:6][CH:7]=1.[C:10]([O:14][C:15]([N:17]1[CH2:21][CH2:20][CH2:19][CH:18]1[CH:22]=O)=[O:16])([CH3:13])([CH3:12])[CH3:11]>C(O)C>[C:10]([O:14][C:15]([N:17]1[CH2:21][CH2:20][CH2:19][CH:18]1[C:22]1[NH:9][C:4]2[CH:3]=[C:2]([Br:1])[CH:7]=[CH:6][C:5]=2[N:8]=1)=[O:16])([CH3:13])([CH3:11])[CH3:12]

Participants

Conditions

Temperature: 80 °C

Procedure

A mixture of 4-bromo-benzene-1,2-diamine (2.4 g) and 2-formyl-pyrrolidine-1-carboxylic acid tert-butyl ester (2.55 g) in ethanol (5 mL) was heated in microwave at 80° C. for 1 hour. Mixture was concentrated and purified by flash column chromatography (silica gel, 20 to 80% ethyl acetate/hexane) to give 2-(6-bromo-1H-benzoimidazol-2-yl)-pyrrolidine-1-carboxylic acid tert-butyl ester (2.6 g, yield 55%). LCMS-ESI−: calc'd for C16H20BrN3O2: 366.25. Found: 365.8 (M+H+).

Workup

concentrationMixture was concentrated
custompurified by flash column chromatography (silica gel, 20 to 80% ethyl acetate/hexane)

Sources & evidence

ORD record: ord-eb962bafbfb041b1843bc17b6d17e666
Source dataset: uspto-grants-2014_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08822430B2

Linked notes

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