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

HRID 2217989Notes

Reaction equation

HRID 2217989 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 precipitated sodium trifluoroacetate crystals are filtered off with suction and washed with dioxane, and the crude solution is reacted further.

Workup

  1. dissolutiondissolves
  2. waitthe mixture is boiled overnight
  3. temperatureAfter cooling
  4. filtrationthe precipitated sodium trifluoroacetate crystals are filtered off with suction
  5. washwashed with dioxane
  6. customthe crude solution is reacted further

Sources & evidence

ORD record
ord-c0c8aa99a95a48dfbbc5adafcd070e42
Source dataset
uspto-grants-2008_08
Patent number
US07410973B2

Reaction notes

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