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

HRID 1241452Notes

Reaction equation

HRID 1241452 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 the sodium salt of ethyl cyanopyruvate (preparation in analogy to Borsche and Manteuffel, Liebigs Ann. 1934, 512, 97) in 2.51 of dioxane under argon with efficient stirring at room temperature, 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 crude solution is reacted further.

Workup

  1. stirringthe mixture is stirred for 10 min, during which most of the precursor
  2. dissolutiondissolves
  3. temperatureAfter cooling
  4. customthe sodium trifluoroacetate crystals which have separated out
  5. filtrationare filtered off with suction
  6. washwashed with dioxane
  7. customthe crude solution is reacted further

Sources & evidence

ORD record
ord-c6ccc52bc05a4100ab0d1265052dab4b
Source dataset
uspto-grants-2006_10
Patent number
US07115599B2

Reaction notes

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