ethyl 4-bromo-1-(5-chloro-2-nitrobenzyl)-1H-pyrrole-2-carboxylate → ethyl 1-(2-amino-5-chlorobenzyl)-4-bromo-1H-pyrrole-2-carboxylate

HRID 1877791Notes

Reaction equation

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

Participants

Conditions

Temperature: 85 °C

Procedure

To a well-stirred solution of ethyl 4-bromo-1-(5-chloro-2-nitrobenzyl)-1H-pyrrole-2-carboxylate (9.1 g, 23.48 mmoles) in acetic acid (60.00 mL) at 70° C., add iron (5 equiv; 6.56 g, 117.38 mmoles) in portions over 0.5 h. Halfway through the addition, observe an exotherm to maintain a temperature of 85° C. with the oil-bath removed. The reaction mixture will get thicker as the exotherm dissipates and the rest of the iron can be added. Stir at 85° C. for 0.5 h. Cool to room temperature and pour onto water (200 mL). Extract into chloroform (2×200 mL). Combine organic layers and wash with water (2×100 mL) then saturated aqueous NaHCO3 solution. Dry over Na2SO4, filter and evaporate to the title compound as an orange oil (7.7 g, 92% yield). MS (m/z): 358.98 (M+1).

Workup

additionHalfway through the addition
customremoved
customThe reaction mixture will get thicker as the exotherm dissipates
temperatureCool to room temperature
additionpour onto water (200 mL)
extractionExtract into chloroform (2×200 mL)
washCombine organic layers and wash with water (2×100 mL)
dry with materialDry over Na2SO4
filtrationfilter

Sources & evidence

ORD record: ord-84757b4506df446cbea882db3a625d12
Source dataset: uspto-grants-2012_11
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08314092B2

Reaction notes

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