N-bromobutanimide → HCID 178509113, compound

HRID 1452745Notes

Reaction equation

HRID 1452745 reaction equation
[NH2:1][C:2]1[NH:6][N:5]=[C:4]([C:7]2[S:8][CH:9]=[CH:10][CH:11]=2)[CH:3]=1.[Br:12]N1C(=O)CCC1=O>C1COCC1>[Br:12][C:3]1[C:4]([C:7]2[S:8][CH:9]=[CH:10][CH:11]=2)=[N:5][NH:6][C:2]=1[NH2:1]

Participants

4

Reactant 2

HCID 67184N-bromobutanimideHCID 178507300HCID 178507300, compound

Product 1

HCID 178509113HCID 178509113, compoundYield 93%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

To a stirring solution of 5-amino-3-(2-thienyl)pyrazole (500 mg, 3.03 mmol) in THF (10 mL) was added N-bromosuccinimide (592 mg, 3.33 mmol) in one portion. The reaction mixture was stirred at room temperature for 3 h, then the solvent was evaporated and the residue was taken up in ethyl acetate. The organic layer was washed successively with 1M aqueous sodium thiosulfate, twice with a saturated aqueous solution of sodium bicarbonate, and brine, then it was dried over sodium sulfate, filtered, and adsorbed on silica gel. Purification on silica gel with 0-10% MeOH in CH2Cl2 as eluent provided 686 mg (93%) of 4-bromo-5-thiophen-2-yl-2H-pyrazol-3-ylamine as a dark foam. 1H-NMR (d6-DMSO) δ: 11.9 and 12.4 (2 broad s, 1H, NH+tautomer), 7.4-7.65 (m, 2H), 7.05-7.2 (m, 1H), 4.8 and 5.3 (2 broad s, 2H, NH2+tautomer).

Workup

  1. customthe solvent was evaporated
  2. washThe organic layer was washed successively with 1M aqueous sodium thiosulfate, twice with a saturated aqueous solution of sodium bicarbonate, and brine
  3. dry with materialit was dried over sodium sulfate
  4. filtrationfiltered
  5. customPurification on silica gel with 0-10% MeOH in CH2Cl2 as eluent

Sources & evidence

ORD record
ord-2569c21b3d34428098edf5b74f49379d
Source dataset
uspto-grants-2009_01
Patent number
US07473783B2

Reaction notes

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