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

HRID 351655Notes

Reaction equation

HRID 351655 reaction equation
[Na].[C:2]([CH2:4][C:5](=O)[C:6]([O:8][CH2:9][CH3:10])=[O:7])#[N:3].FC(F)(F)C(O)=O.[F:19][C:20]1[CH:28]=[CH:27][CH:26]=[CH:25][C:21]=1[CH2:22][NH:23][NH2:24]>O1CCOCC1>[NH2:3][C:2]1[N:23]([CH2:22][C:21]2[CH:25]=[CH:26][CH:27]=[CH:28][C:20]=2[F:19])[N:24]=[C:5]([C:6]([O:8][CH2:9][CH3:10])=[O:7])[CH:4]=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

Under argon, 100 g (0.613 mol) of the sodium salt of ethyl cyanopyruvate (preparation analogously to Borsche and Manteuffel, Liebigs Ann. 1934, 512, 97) in 2.5 l of dioxane are admixed, with efficient stirring and at room temperature, with 111.75 g (75 ml, 0.98 mol) of trifluoroacetic acid, and the mixture is stirred for 10 min, during which a large proportion of the starting material dissolves. 85.93 g (0.613 mol) of 2-fluorobenzylhydrazine are then 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-cd147afe3d784b688ddc7af8a4c6cf13
Source dataset
uspto-grants-2004_06
Patent number
US06743798B1

Reaction notes

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