Acetic Anhydride → 1-(5-(Benzyloxy)-1H-indazol-1-yl)ethan-1-one

HRID 25379Notes

Reaction equation

HRID 25379 reaction equation
[C:1]([O:4]C(=O)C)(=O)[CH3:2].[CH2:8]([O:15][C:16]1[CH:22]=[CH:21][C:19]([NH2:20])=[C:18]([CH3:23])[CH:17]=1)[C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][CH:10]=1.[N:24](OC(C)(C)C)=O>C1(C)C=CC=CC=1>[C:1]([N:20]1[C:19]2[C:18](=[CH:17][C:16]([O:15][CH2:8][C:9]3[CH:10]=[CH:11][CH:12]=[CH:13][CH:14]=3)=[CH:22][CH:21]=2)[CH:23]=[N:24]1)(=[O:4])[CH3:2]

Participants

5

Reactant 3

HCID 7918Acetic AnhydrideHCID 10906Tert-Butyl nitriteHCID 167730534-(Benzyloxy)-2-methylaniline

Product 1

HCID 225672491-(5-(Benzyloxy)-1H-indazol-1-yl)ethan-1-one

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Conditions

Temperature
90 °C

Procedure

1-Acetyl-5-benzyloxy-1H-indazole can be obtained in the following way: 0.8 ml of acetic anhydride is run into a solution of 500 mg of 4-benzyloxy-2-methylaniline in 3 ml of toluene and the reaction medium is heated at a temperature in the region of 90° C. for 1 hour. 0.55 ml of tert-butyl nitrite is run in dropwise into this solution at approximately 90° C. Heating is continued for 1 hour 30 minutes and then the reaction medium is cooled to a temperature in the region of 20° C. and concentrated to dryness under reduced pressure. The solid residue is taken up with 5 ml of chloroform and the organic phase is washed with 4 ml of a 5% aqueous potassium carbonate solution, dried over magnesium sulfate, filtered and concentrated by evaporation under reduced pressure. The solid thus obtained is purified by chromatography on a silica column with a dichloromethane/cyclohexane (9/1 by volume) mixture as eluent. 467 mg of 1-acetyl-5-benzyloxy-1H-indazole are thus obtained in the form of a brown powder (Rf=0.54, silica gel thin layer chromatography, eluent: cyclohexane/dichloromethane (1/9 by volume)).

Workup

  1. customat approximately 90° C
  2. temperatureHeating
  3. temperaturethe reaction medium is cooled to a temperature in the region of 20° C.
  4. concentrationconcentrated to dryness under reduced pressure
  5. washthe organic phase is washed with 4 ml of a 5% aqueous potassium carbonate solution
  6. dry with materialdried over magnesium sulfate
  7. filtrationfiltered
  8. concentrationconcentrated by evaporation under reduced pressure
  9. customThe solid thus obtained
  10. customis purified by chromatography on a silica column with a dichloromethane/cyclohexane (9/1 by volume) mixture as eluent

Sources & evidence

ORD record
ord-040cd259b5fe464a8d89ac4699cabedd
Source dataset
uspto-grants-2005_02
Patent number
US06858638B2

Reaction notes

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