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

HRID 2120566Notes

Reaction equation

HRID 2120566 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

100 g (0.613 mol) of sodium salt of ethyl cyanopyruvate (preparation analogously to Borsche and Manteuffel, Liebigs Ann. 1934, 512, 97) are treated with 111.75 g (75 ml, 0.98 mol) of trifluoroacetic acid at room temperature in 2.5 l of dioxane under argon with good stirring and the mixture is stirred for 10 min, a large part of the starting material going into solution. 85.93 g (0.613 mol) of 2-fluorobenzylhydrazine are then added and the mixture is boiled overnight. After cooling, the deposited crystals of sodium trifluoroacetate are filtered off with suction, washed with dioxane and the solution is reacted further in crude form.

Workup

  1. stirringthe mixture is stirred for 10 min
  2. temperatureAfter cooling
  3. filtrationthe deposited crystals of sodium trifluoroacetate are filtered off with suction
  4. washwashed with dioxane
  5. customthe solution is reacted further in crude form

Sources & evidence

ORD record
ord-63cc2b50ff564de8b80985800dce3e3a
Source dataset
uspto-grants-2004_02
Patent number
US06693102B2

Reaction notes

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