Sodium Bicarbonate → 3-bromo-2-pyridin-2-yl-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole

HRID 2221150Notes

Reaction equation

HRID 2221150 reaction equation
[N:1]1[CH:6]=[CH:5][CH:4]=[CH:3][C:2]=1[C:7]1[C:8](C(O)=O)=[C:9]2[CH2:14][CH2:13][CH2:12][N:10]2[N:11]=1.C(=O)(O)[O-].[Na+].[Br:23]NC(=O)CCC(N)=O>CN(C=O)C.O.C(OCC)(=O)C>[Br:23][C:8]1[C:7]([C:2]2[CH:3]=[CH:4][CH:5]=[CH:6][N:1]=2)=[N:11][N:10]2[CH2:12][CH2:13][CH2:14][C:9]=12

Participants

7

Reactant 3

HCID 516892Sodium BicarbonateHCID 9834204N-BromosuccinamideHCID 597100292-(Pyridin-2-yl)-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole-3-carboxylic Acid

Product 1

HCID 597100253-bromo-2-pyridin-2-yl-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazoleYield 70.5%

Reagents, catalysts & solvents 3

HCID 962WaterSolventHCID 6228DimethylformamideSolventHCID 8857Ethyl AcetateSolvent

Procedure

Stir a mixture of 2-(pyridin-2-yl)-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole-3-carboxylic acid (2 g, 8.7 mmol), sodium bicarbonate (3.3 g, 38.4 mmol), and N-bromosuccinamide (1.7 g, 9.6 mmol) in DMF (50 mL) at room temperature for 2 h. Dilute the crude mixture with water (50 mL) and ethyl acetate (100 mL). Separate the ethyl acetate layer, extract with saturated sodium chloride solution, dry over anhydrous sodium sulfate, filter, and evaporate to a solid mass. Purify by MPLC (SiO2, 1:1 ethyl acetate/hexane) to obtain 1.62 g (70%) of the title compound as a cream solid. MS ES+ m/e 264 (M+1), MS ES+ m/e 266 (M+2).

Workup

  1. customSeparate the ethyl acetate layer
  2. extractionextract with saturated sodium chloride solution
  3. dry with materialdry over anhydrous sodium sulfate
  4. filtrationfilter
  5. customevaporate to a solid mass
  6. customPurify by MPLC (SiO2, 1:1 ethyl acetate/hexane)

Sources & evidence

ORD record
ord-a2229310588546a184d91c6467f24989
Source dataset
uspto-grants-2008_05
Patent number
US07368445B2

Reaction notes

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