Hydrazine hydrate (1:1) → 6-Fluoro-3-(2-fluorobenzyl)-1H-pyrazolo[4,3-b]pyridine

HRID 510040Notes

Reaction equation

HRID 510040 reaction equation
F[C:2]1[C:3]([C:9](=O)[CH2:10][C:11]2[CH:16]=[CH:15][CH:14]=[CH:13][C:12]=2[F:17])=[N:4][CH:5]=[C:6]([F:8])[CH:7]=1.O.[NH2:20][NH2:21]>N1C=CC=CC=1.CN(C)C1C=CN=CC=1.C(OCC)(=O)C>[F:8][C:6]1[CH:7]=[C:2]2[NH:21][N:20]=[C:9]([CH2:10][C:11]3[CH:16]=[CH:15][CH:14]=[CH:13][C:12]=3[F:17])[C:3]2=[N:4][CH:5]=1

Participants

6

Reactant 2

HCID 24654Hydrazine hydrate (1:1)HCID 666355431-(3,5-Difluoropyridin-2-yl)-2-(2-fluorophenyl)ethanone

Product 1

HCID 1785059746-Fluoro-3-(2-fluorobenzyl)-1H-pyrazolo[4,3-b]pyridine

Reagents, catalysts & solvents 3

HCID 142844-(Dimethylamino)pyridineCatalystHCID 1049PyridineSolventHCID 8857Ethyl AcetateSolvent

Procedure

9.07 g (32.4 mmol) of the compound from example 37A were initially charged in pyridine (84 ml). Subsequently, 8.10 g (162 mmol) of hydrazine hydrate and 19.8 mg (0.162 mmol) of 4-dimethylaminopyridine were added, and the mixture was heated to reflux for 30 min. The reaction mixture was diluted with ethyl acetate at RT and washed four times with 10% aqueous citric acid solution. The organic phase was subsequently washed with saturated aqueous sodium chloride solution, dried over sodium sulfate, filtered and concentrated. The residue was admixed with tert-butyl methyl ether and the solids were filtered off. The latter were dried under high vacuum and gave 1.79 g (79% purity, 18% of theory) of the title compound. The filtrate was concentrated and gave a further 4.86 g (61% purity, 37% of theory) of the title compound. The two fractions were combined and converted without further purification.

Workup

  1. temperaturethe mixture was heated
  2. temperatureto reflux for 30 min
  3. washwashed four times with 10% aqueous citric acid solution
  4. washThe organic phase was subsequently washed with saturated aqueous sodium chloride solution
  5. dry with materialdried over sodium sulfate
  6. filtrationfiltered
  7. concentrationconcentrated
  8. filtrationthe solids were filtered off
  9. customThe latter were dried under high vacuum

Sources & evidence

ORD record
ord-27dd8e765fb8447487352b03d83dea0f
Source dataset
uspto-grants-2015_08
Patent number
US09096592B2

Reaction notes

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