Hydrochloric Acid → Ethyl 1-(5-bromopyridin-2-yl)-5-methylpyrazole-4-carboxylate

HRID 1748436Notes

Reaction equation

HRID 1748436 reaction equation
[Br:1][C:2]1[CH:3]=[CH:4][C:5]([NH:8][NH2:9])=[N:6][CH:7]=1.C(O[CH:13]=[C:14]([C:20]([CH3:22])=O)[C:15]([O:17][CH2:18][CH3:19])=[O:16])C.Cl>C(O)C>[CH2:18]([O:17][C:15]([C:14]1[CH:13]=[N:9][N:8]([C:5]2[CH:4]=[CH:3][C:2]([Br:1])=[CH:7][N:6]=2)[C:20]=1[CH3:22])=[O:16])[CH3:19]

Participants

5

Reactant 3

HCID 313Hydrochloric AcidHCID 97734Butanoic acid, 2-(ethoxymethylene)-3-oxo-, ethyl esterHCID 115356995-Bromo-2-hydrazinopyridine

Product 1

HCID 46739344Ethyl 1-(5-bromopyridin-2-yl)-5-methylpyrazole-4-carboxylateYield 73.3%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

Next, 5-bromopyridin-2-ylhydrazine (25.3 g) and ethyl 2-ethoxymethyleneacetoacetate (25.1 g) prepared according to a method described in J. Chem. Soc. Perkin trans. I, 1875 (1988), were added to a mixed solvent of 1N hydrochloric acid aqueous solution (320 ml) and ethanol (370 ml), stirred at reflux temperature for 4.5 hours and the solvent was evaporated in vacuo. Water was added to the residue, the precipitated solid was washed with water and recrystallized from a mixed solvent of ethyl acetate and n-hexane to give 1-(5-bromopyridin-2-yl)-5-methyl-1H-pyrazole-4-carboxylic acid ethyl ester (30.6 g) as a pale yellow solid.

Workup

  1. temperatureat reflux temperature for 4.5 hours
  2. customthe solvent was evaporated in vacuo
  3. additionWater was added to the residue
  4. washthe precipitated solid was washed with water
  5. customrecrystallized from a mixed solvent of ethyl acetate and n-hexane

Sources & evidence

ORD record
ord-743fd6dbfd5d4a00a96e96540ce2abb3
Source dataset
uspto-grants-2015_10
Patent number
US09150555B2

Reaction notes

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