Hydrochloric Acid → 3-(4-Bromo-phenyl)-pyrrole-2,5-dione

HRID 1400027Notes

Reaction equation

Cl.[Br:2][C:3]1[CH:9]=[CH:8][C:6](N)=[CH:5][CH:4]=1.N([O-])=O.[Na+].[C:14]1(=[O:20])[NH:18][C:17](=[O:19])[CH:16]=[CH:15]1.C([O-])(=O)C.[Na+]>O.CC(C)=O>[Br:2][C:3]1[CH:9]=[CH:8][C:6]([C:16]2[C:17](=[O:19])[NH:18][C:14](=[O:20])[CH:15]=2)=[CH:5][CH:4]=1

Participants

Conditions

Temperature: 0 °C

Procedure

A solution of hydrochloric acid (37%, 13 mL) in water (5.5 mL) was added to 4-bromoaniline (7.48 g, 43.52 mmol) at r.t. with vigorous stirring and the formed precipitate was allowed to stir for 30 min. The reaction mixture was cooled to 0° C. and a solution of sodium nitrite (3.30 g, 47.87 mmol) in water (9 mL) was added dropwise. At the end of diazotization, a clear yellow solution was obtained. Maleimide (8.45 g, 87.05 mmol) in acetone (35 mL) was added dropwise at 0° C. and then the pH of the solution was adjusted to 3-3.5 by adding sodium acetate. CuCl2 (0.88 g, 6.57 mmol) was added to the vigorously stirred mixture. The reaction mixture was stirred at 0° C. for 1 h and overnight at r.t. After completion of the reaction as confirmed by TLC, solvents were removed in vacuo to afford the crude compound, which was purified by column chromatography (silica gel, 4:6 EtOAc:Pet. ether) to afford the title compound as a yellow solid (5.8 g, 57%).

Workup

stirringto stir for 30 min
customAt the end of diazotization, a clear yellow solution was obtained
stirringThe reaction mixture was stirred at 0° C. for 1 h and overnight at r.t
customAfter completion of the reaction
customwere removed in vacuo
customto afford the crude compound, which
customwas purified by column chromatography (silica gel, 4:6 EtOAc:Pet. ether)

Sources & evidence

ORD record: ord-4c53b41bbca941f1948ff63351e4df7a
Source dataset: uspto-grants-2014_12
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08906913B2

Reaction notes

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