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

HRID 751261Notes

Reaction equation

HRID 751261 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 (Preparation 3; 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 50 mL of water and 100 mL of ethyl acetate. Separate the ethyl acetate layer, extract with saturated brine, dry over anhydrous sodium sulfate, filter, and evaporate to a solid mass. Purify by MPLC (SiO2, 50% ethyl acetate-hexane) to obtain the title compound (1.62 g, 70%) 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 brine
  3. dry with materialdry over anhydrous sodium sulfate
  4. filtrationfilter
  5. customevaporate to a solid mass
  6. customPurify by MPLC (SiO2, 50% ethyl acetate-hexane)

Sources & evidence

ORD record
ord-baa6149b86a2430aacd631a80e97750f
Source dataset
uspto-grants-2008_07
Patent number
US07405299B2

Reaction notes

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