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

HRID 2203347Notes

Reaction equation

HRID 2203347 reaction equation
Cl[C:2]1[C:7]([CH:8]=O)=[CH:6][CH:5]=[CH:4][N:3]=1.O.[NH2:11][NH2:12]>O.CCOC(C)=O>[NH:11]1[C:2]2=[N:3][CH:4]=[CH:5][CH:6]=[C:7]2[CH:8]=[N:12]1

Participants

5

Reactant 2

HCID 24654Hydrazine hydrate (1:1)HCID 7376072-Chloro-3-pyridinecarboxaldehyde

Product 1

HCID 27558501H-pyrazolo(3,4-b)pyridine

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 8857Ethyl AcetateSolvent

Procedure

A solution of 2-chloropyridine-3-carbaldehyde (20 g, 141 mmol) and hydrazine monohydrate (60% in water, 113 g, 2.1 mol) in 140 mL water was heated at 100° C. for 72 hours. The reaction mixture was cooled to room temperature and diluted with 200 mL of EtOAc. The aqueous layer was separated and extracted with EtOAc (3×). The combined organics were dried over MgSO4, filtered and concentrated in vacuo to give a light orange solid which was crystallized from hexanes to give the title compound as an off-white solid. 1H NMR (400 MHz, CH3CN-d3): δ 11.56 (s, 1H); 8.51 (dd, J=4.52, 1.56 Hz, 1H); 8.17 (dd, J=8.05, 1.58 Hz, 1H); 8.05 (s, 1H); 7.17 (dd, J=8.05, 4.51 Hz, 1H).

Workup

  1. customThe aqueous layer was separated
  2. extractionextracted with EtOAc (3×)
  3. dry with materialThe combined organics were dried over MgSO4
  4. filtrationfiltered
  5. concentrationconcentrated in vacuo
  6. customto give a light orange solid which
  7. customwas crystallized from hexanes

Sources & evidence

ORD record
ord-2aa1c1b2aac049e3910a2f1ab5c4fd69
Source dataset
uspto-grants-2016_06
Patent number
US09365574B2

Reaction notes

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