2-Bromo-4'-nitroacetophenone → Ethyl 2-amino-5-(4-nitrophenyl)-1H-pyrrole-3-carboxylate

HRID 369708Notes

Reaction equation

HRID 369708 reaction equation
Cl.[CH2:2]([O:4][C:5](=[O:10])[CH2:6][C:7](=[NH:9])[NH2:8])[CH3:3].C([O-])C.[Na+].Br[CH2:16][C:17]([C:19]1[CH:24]=[CH:23][C:22]([N+:25]([O-:27])=[O:26])=[CH:21][CH:20]=1)=O>C(O)C>[NH2:9][C:7]1[NH:8][C:17]([C:19]2[CH:20]=[CH:21][C:22]([N+:25]([O-:27])=[O:26])=[CH:23][CH:24]=2)=[CH:16][C:6]=1[C:5]([O:4][CH2:2][CH3:3])=[O:10]

Participants

5

Reactant 3

HCID 668402-Bromo-4'-nitroacetophenoneHCID 2723922Sodium ethoxideHCID 15555354Ethyl 2-carbamimidoylacetate hydrochloride

Product 1

HCID 21262647Ethyl 2-amino-5-(4-nitrophenyl)-1H-pyrrole-3-carboxylate

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

In a dry three-necked flask, under argon, 75 ml of abs. ethanol and 6.5 g (390 mmol) of 2-amidino-acetic acid ethyl ester hydrochloride [preparation see: Liebigs Ann. Chem., 1895 (1977)] are cooled to 0-5° C. and 2.65 g (390 mmol) of sodium ethanolate are added. 5 g (195 mmol) of 2-bromo-1-(4-nitro-phenyl)-ethan-1-one are then added and the mixture is allowed to rise to room temperature and is stirred for a further 48 hours. The reaction mixture is then partitioned between water and ethyl acetate. The ethyl acetate phase is washed three times with water and once with sat. NaCl solution, dried and filtered, and the filtrate is concentrated by evaporation. The reddish-brown residue is made into a slurry in hexane, the title compound precipitating in the form of a crude product (purity 93%) which is used for the next step without further purification; MS: (M)+ =275.

Workup

  1. customto rise to room temperature
  2. customThe reaction mixture is then partitioned between water and ethyl acetate
  3. washThe ethyl acetate phase is washed three times with water
  4. dry with materialonce with sat. NaCl solution, dried
  5. filtrationfiltered
  6. concentrationthe filtrate is concentrated by evaporation
  7. customthe title compound precipitating in the form of a crude product (purity 93%) which
  8. customis used for the next step without further purification

Sources & evidence

ORD record
ord-3277198f8d4641eaa571e274b09fce9e
Source dataset
uspto-grants-2000_10
Patent number
US06140317

Reaction notes

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