4-Nitroaniline → 3-(4-nitrophenyl)-1H-imidazo[4,5-b]pyridin-2-one

HRID 82556Notes

Reaction equation

HRID 82556 reaction equation
Cl[C:2]1[C:7]([NH:8][C:9](=[O:15])OC(C)(C)C)=[CH:6][CH:5]=[CH:4][N:3]=1.[N+:16]([C:19]1[CH:25]=[CH:24][C:22]([NH2:23])=[CH:21][CH:20]=1)([O-:18])=[O:17].CC1(C)C2C=CC=C(P(C3C=CC=CC=3)C3C=CC=CC=3)C=2OC2C1=CC=CC=2P(C1C=CC=CC=1)C1C=CC=CC=1.CC(C)([O-])C.[Na+]>C1(C)C=CC=CC=1.C1C=CC(/C=C/C(/C=C/C2C=CC=CC=2)=O)=CC=1.C1C=CC(/C=C/C(/C=C/C2C=CC=CC=2)=O)=CC=1.C1C=CC(/C=C/C(/C=C/C2C=CC=CC=2)=O)=CC=1.[Pd].[Pd].CC(O)C>[N+:16]([C:19]1[CH:25]=[CH:24][C:22]([N:23]2[C:2]3=[N:3][CH:4]=[CH:5][CH:6]=[C:7]3[NH:8][C:9]2=[O:15])=[CH:21][CH:20]=1)([O-:18])=[O:17]

Participants

8

Reactant 4

HCID 74754-NitroanilineHCID 6360441,1'-(9,9-Dimethyl-9H-xanthene-4,5-diyl)bis(1,1-diphenylphosphine)HCID 11961738tert-Butyl (2-chloropyridin-3-yl)carbamateHCID 23676156Sodium t-butoxide

Product 1

HCID 9155343-(4-nitrophenyl)-1H-imidazo[4,5-b]pyridin-2-oneYield 35.7%

Reagents, catalysts & solvents 3

HCID 9811564Bis(dibenzylideneacetone)palladiumCatalystHCID 1140TolueneSolventHCID 3776IsopropanolSolvent

Conditions

Temperature
100 °C

Procedure

The mixture of tert-butyl 2-chloropyridin-3-ylcarbamate (10.0 g), 4-nitroaniline (8.0 g), 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene (2.53 g), Pd2(dba)3 (2 g) and sodium tert-butoxide (12.5 g) in toluene (160 mL)-2-propanol (40.0 mL) was stirred at 100° C. under Ar overnight. The reaction mixture was concentrated in vacuo. The residue was purified by column chromatography (silica gel, eluted with 0%-100% EtOAc in hexane) to give 3-(4-nitrophenyl)-1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-one (4.0 g) as a light brown solid. A mixture of 3-(4-nitrophenyl)-1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-one (3.50 g), sodium hydride (0.400 g) and iodoethane (2.0 mL) in DMF (40 mL) was stirred at 20° C. under a dry atmosphere (CaCl2 tube) for 1 h. The mixture was concentrated under reduced pressure. The residue was purified by column chromatography (NH silica gel, eluted with 0%-30% EtOAc in hexane) to give 1-ethyl-3-(4-nitrophenyl)-1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-one (2.70 g) as a brown solid. A mixture of 1-ethyl-3-(4-nitrophenyl)-1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-one (2.70 g) and 10% palladium-carbon (0.832 g) in EtOH (250 mL) was hydrogenated under balloon pressure at room temperature for 3 h. The catalyst was removed by filtration and the filtrate was concentrated in vacuo to give 3-(4-aminophenyl)-1-ethyl-1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-one (1.00 g) as a brown solid.

Workup

  1. concentrationThe reaction mixture was concentrated in vacuo
  2. customThe residue was purified by column chromatography (silica gel, eluted with 0%-100% EtOAc in hexane)

Sources & evidence

ORD record
ord-f8c3b2eda9184cba8083a9ec9d41d4e4
Source dataset
uspto-grants-2014_09
Patent number
US08846713B2

Reaction notes

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