Hydrazine hydrate (1:1) → 1H-pyrazolo(3,4-b)pyridine

HRID 2070017Notes

Reaction equation

HRID 2070017 reaction equation
[CH:1]1[CH:6]=[N:5][C:4](Cl)=[C:3]([CH:8]=O)[CH:2]=1.O.C1(C)C=CC(S(O)(=O)=O)=CC=1.O.[NH2:23][NH2:24].C(=O)(O)[O-].[Na+]>>[NH:23]1[C:4]2=[N:5][CH:6]=[CH:1][CH:2]=[C:3]2[CH:8]=[N:24]1

Participants

5

Reactant 4

HCID 24654Hydrazine hydrate (1:1)HCID 516892Sodium BicarbonateHCID 521998p-Toluenesulfonic acid monohydrateHCID 7376072-Chloro-3-pyridinecarboxaldehyde

Product 1

HCID 27558501H-pyrazolo(3,4-b)pyridineYield 62%

Conditions

Temperature
120 °C

Procedure

2-Chloro-3-pyridinecarboxyaldehyde (1.0 g, 7.0 mmol) and p-toluenesulfonic acid monohydrate (700 mg) were dissolved in hydrazine monohydrate (1.4 mL, 28.0 mmol). The resulting mixture was heated at 120° C. for 10 minutes in a sealed tube under irradiation with a macrowave of 100 watts. After cooled to room temperature, the mixture was neutralized with a saturated sodium bicarbonate aqueous solution and extracted with DCM (50 mL) three times. The organic layer was dried over anhydrous sodium sulfate. The concentrated residue was purified by silica gel (Fuji Silysia, BW300, 30 g, n-hexane:ethyl acetate=1:1) to give 1H-pyrazolo[3,4-b]pyridine (513 mg, yield: 62%).

Workup

  1. temperatureAfter cooled to room temperature
  2. extractionextracted with DCM (50 mL) three times
  3. dry with materialThe organic layer was dried over anhydrous sodium sulfate
  4. customThe concentrated residue was purified by silica gel (Fuji Silysia, BW300, 30 g, n-hexane:ethyl acetate=1:1)

Sources & evidence

ORD record
ord-436d6f3e20a644bea514b6a718496545
Source dataset
uspto-grants-2012_10
Patent number
US08299252B2

Reaction notes

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