Trifluoroacetic acid → ethyl 5-amino-1-(2-fluorobenzyl)-1H-pyrazole-3-carboxylate

HRID 8570Notes

Reaction equation

HRID 8570 reaction equation
FC(F)(F)C(O)=O.[Na].[C:9]([CH2:11][C:12](=O)[C:13]([O:15][CH2:16][CH3:17])=[O:14])#[N:10].[F:19][C:20]1[CH:28]=[CH:27][CH:26]=[CH:25][C:21]=1[CH2:22][NH:23][NH2:24]>O1CCOCC1>[NH2:10][C:9]1[N:23]([CH2:22][C:21]2[CH:25]=[CH:26][CH:27]=[CH:28][C:20]=2[F:19])[N:24]=[C:12]([C:13]([O:15][CH2:16][CH3:17])=[O:14])[CH:11]=1

Participants

6

Reactant 4

HCID 6422Trifluoroacetic acidHCID 5360545SodiumHCID 10374537(2-Fluorobenzyl)hydrazineHCID 11309560Ethyl 3-cyano-2-oxopropanoate

Product 1

HCID 11391384ethyl 5-amino-1-(2-fluorobenzyl)-1H-pyrazole-3-carboxylate

Reagents, catalysts & solvents 1

HCID 312751,4-DioxaneSolvent

Procedure

111.75 g (75 ml, 0.98 mol) of trifluoroacetic acid are added to 100.00 g (0.613 mol) of the sodium salt of ethyl cyanopyruvate (prepared in analogy to Borsche and Manteuffel, Liebigs Ann. 1934, 512, 97) while stirring efficiently in 2.5 l of dioxane at room temperature under argon, and the mixture is stirred for 10 min, during which most of the precursor dissolves. Then 85.93 g (0.613 mol) of 2-fluorobenzyl-hydrazine are added, and the mixture is boiled overnight. After cooling, the sodium trifluoroacetate crystals which have separated out are filtered off with suction and washed with dioxane, and the remaining crude solution is reacted further.

Workup

  1. dissolutiondissolves
  2. waitthe mixture is boiled overnight
  3. temperatureAfter cooling
  4. customthe sodium trifluoroacetate crystals which have separated out
  5. filtrationare filtered off with suction
  6. washwashed with dioxane
  7. customthe remaining crude solution is reacted further

Sources & evidence

ORD record
ord-347c075934a74b70a106dd279acbdf62
Source dataset
uspto-grants-2006_08
Patent number
US07091198B1

Reaction notes

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