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

HRID 346526Notes

Reaction equation

HRID 346526 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 g (0.613 mol) of sodium salt of ethyl cyanopyruvate (prepared in analogy to Borsche and Manteuffel, Liebigs Ann. 1934, 512, 97) in 2.5 l of dioxane under argon with efficient stirring at room temperature, and the mixture is stirred for 10 minutes during which much of the precursor dissolves. Then 85.93 g (0.613 mol) of 2-fluorobenzylhydrazine are added, and the mixture is heated under reflux overnight. After cooling, the crystals of sodium trifluoroacetate which have separated out are filtered off with suction and washed with dioxane, and the solution is reacted further as it is.

Workup

  1. stirringthe mixture is stirred for 10 minutes during which much of the precursor
  2. dissolutiondissolves
  3. temperaturethe mixture is heated
  4. temperatureunder reflux overnight
  5. temperatureAfter cooling
  6. customthe crystals of sodium trifluoroacetate which have separated out
  7. filtrationare filtered off with suction
  8. washwashed with dioxane
  9. customthe solution is reacted further as it

Sources & evidence

ORD record
ord-9a5b697519de4de7926276d57e7d7215
Source dataset
uspto-grants-2007_02
Patent number
US07173037B2

Reaction notes

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