Pyrazol-3-ylamine → 5-Bromopyrazolo[3,4-b]pyridine

HRID 1943859Notes

Reaction equation

HRID 1943859 reaction equation
[NH:1]1[C:5]([NH2:6])=[CH:4][CH:3]=[N:2]1.[Br:7][CH:8]([CH:11]=O)[CH:9]=O>C(O)(=O)C.CO>[Br:7][C:8]1[CH:9]=[C:4]2[CH:3]=[N:2][NH:1][C:5]2=[N:6][CH:11]=1

Participants

5

Reactant 2

HCID 74561Pyrazol-3-ylamineHCID 749452-Bromopropanedial

Product 1

HCID 404274545-Bromopyrazolo[3,4-b]pyridineYield 25%

Reagents, catalysts & solvents 2

HCID 176Acetic AcidSolventHCID 887MethanolSolvent

Procedure

1H-Pyrazol-5-amine (5.3 g, 64 mmol) and 2-bromomalonaldehyde (9.9 g, 64 mmol) were suspended in acetic acid (100 mL). The reaction mixture was heated to reflux under N2 for 6 hours. The reaction mixture was cooled to room temperature and concentrated to give a solid. The crude solids were suspended in MeOH (200 mL) and absorbed onto silica gel (200 g). The crude product was purified by column chromatography, eluting with hexanes/ethyl acetate (4:1), hexanes/ethyl acetate (2:1) to give 5-bromo-1H-pyrazolo[3,4-b]pyridine as a solid (3.1 g, 25%).

Workup

  1. temperatureThe reaction mixture was heated
  2. temperatureto reflux under N2 for 6 hours
  3. concentrationconcentrated
  4. customto give a solid
  5. customabsorbed onto silica gel (200 g)
  6. customThe crude product was purified by column chromatography
  7. washeluting with hexanes/ethyl acetate (4:1), hexanes/ethyl acetate (2:1)

Sources & evidence

ORD record
ord-3fa0dff8dad541fe8533e3648b6a6276
Source dataset
uspto-grants-2013_03
Patent number
US08394795B2

Reaction notes

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