Acetonitrile → ethyl 4-bromo-3,5-dimethyl-1H-pyrrole-2-carboxylate

HRID 1372416Notes

Reaction equation

HRID 1372416 reaction equation
[CH2:1]([O:3][C:4]([C:6]1[NH:7][C:8]([CH3:12])=[CH:9][C:10]=1[CH3:11])=[O:5])[CH3:2].C(=O)([O-])[O-].[K+].[K+].C(#N)C.[Br:22]N1C(=O)CCC1=O>O>[CH2:1]([O:3][C:4]([C:6]1[NH:7][C:8]([CH3:12])=[C:9]([Br:22])[C:10]=1[CH3:11])=[O:5])[CH3:2]

Participants

6

Reactant 4

HCID 6342AcetonitrileHCID 11430Potassium CarbonateHCID 67184N-bromobutanimideHCID 1374771H-Pyrrole-2-carboxylic acid, 3,5-dimethyl-, ethyl ester

Product 1

HCID 138486ethyl 4-bromo-3,5-dimethyl-1H-pyrrole-2-carboxylateYield 76%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
4 °C

Procedure

3,5-Dimethyl-1H-pyrrole-2-carboxylic acid ethyl ester (204 g), 177 g of potassium carbonate and 1428 mL of acetonitrile were stirred and cooled to 4° C. in an ice bath. N-Bromosuccinimide (228 g) was added in portions with vigorous stirring keeping the temperature below 17° C. The mixture was warmed to 20° C. and 2856 mL of water was slowly added. The mixture was stirred for 30 minutes. The precipitate was collected by vacuum filtration and washed three times with 400 mL of ethanol:water 1:2 each time. The solids were dried under vacuum at 60° C. to give 228 g (76% yield) of 4-bromo-3,5-dimethyl-1H-pyrrole-2-carboxylic acid ethyl ester as an off-white solid. 1H-NMR (dimethylsulfoxide-d6) δ 1.26 (t, 3H, CH3), 2.14, 2.17 (2×s, 2×3H, 2×CH3), 4.20 (d, 2H, CH2O), 11.75 (br s, 1H, NH). MS m/z 246, 248 [M+1].

Workup

  1. customthe temperature below 17° C
  2. temperatureThe mixture was warmed to 20° C.
  3. stirringThe mixture was stirred for 30 minutes
  4. filtrationThe precipitate was collected by vacuum filtration
  5. washwashed three times with 400 mL of ethanol:water 1:2 each time
  6. customThe solids were dried under vacuum at 60° C.

Sources & evidence

ORD record
ord-ad3bc2893b15485b937937248073c3aa
Source dataset
uspto-grants-2007_01
Patent number
US07157577B2

Reaction notes

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