Hydrogen phosphate → 1H-Indazole-5-carboxaldehyde

HRID 1531807Notes

Reaction equation

HRID 1531807 reaction equation
[C:1]([C:3]1[CH:4]=[C:5]2[C:9](=[CH:10][CH:11]=1)[NH:8][N:7]=[CH:6]2)#N.P([O-])([O-])(O)=[O:13]>O.C(O)(=O)C.N1C=CC=CC=1.[Ni].O>[NH:8]1[C:9]2[C:5](=[CH:4][C:3]([CH:1]=[O:13])=[CH:11][CH:10]=2)[CH:6]=[N:7]1

Participants

7

Reactant 2

HCID 3681305Hydrogen phosphateHCID 111263841H-Indazole-5-carbonitrile

Product 1

HCID 212506441H-Indazole-5-carboxaldehydeYield 99.6%

Reagents, catalysts & solvents 4

HCID 444642Hydroxy-nickelCatalystHCID 176Acetic AcidSolventHCID 962WaterSolventHCID 1049PyridineSolvent

Conditions

Temperature
50 °C

Procedure

5-Cyanoindazole (2.32 g) [Hailey etc Synthetic communications, (1997), 27 (7), 1199-1207] was dissolved in a mixture of water (16.7 ml ), glacial acetic acid (16.7 ml ) and pyridine (33.4 ml) under a atmosphere of nitrogen. Sodiun hydrogen phosphate (4.64 g) was added to the mixture followed by raney nickel/ water (2 g/ml). The reaction mixture was heated to 50° C. for 5 hrs and then allowed to cool to room temperature and stirred for 18 hrs. The catalyst was then filtered off and washed with pyridine and water. The pH of the solution was adjusted to 9.0 with sodium carbonate and the product extracted with ethyl acetate (×2). The organic layers were dried over MgSO4 and evaporated under reduced pressure. The crude solid was purified by washing with toluene to afford the title compound as a beige solid (2.36 g).

Workup

  1. temperatureto cool to room temperature
  2. filtrationThe catalyst was then filtered off
  3. washwashed with pyridine and water
  4. extractionthe product extracted with ethyl acetate (×2)
  5. dry with materialThe organic layers were dried over MgSO4
  6. customevaporated under reduced pressure
  7. customThe crude solid was purified
  8. washby washing with toluene

Sources & evidence

ORD record
ord-5daf79bc5a1b45cea54c7c686e4e72dd
Source dataset
uspto-grants-2001_03
Patent number
US06200978B1

Reaction notes

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