Chlorosuccinimide → ethyl 4-chloro-5-methyl-1H-pyrazole-3-carboxylate

HRID 499254Notes

Reaction equation

HRID 499254 reaction equation
[CH3:1][C:2]1[NH:6][N:5]=[C:4]([C:7]([O:9][CH2:10][CH3:11])=[O:8])[CH:3]=1.[Cl:12]N1C(=O)CCC1=O>CN(C=O)C>[CH2:10]([O:9][C:7]([C:4]1[C:3]([Cl:12])=[C:2]([CH3:1])[NH:6][N:5]=1)=[O:8])[CH3:11]

Participants

4

Reactant 2

HCID 31398ChlorosuccinimideHCID 77645Ethyl 5-methyl-1H-pyrazole-3-carboxylate

Product 1

HCID 604759ethyl 4-chloro-5-methyl-1H-pyrazole-3-carboxylate

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

To a magnetically stirred solution of ethyl 5-methyl-1H-pyrazole-3-carboxylate (3 mmol) in 10 mL of anhydrous DMF at 0° C. is added N-chlorosuccinimide (4 mmol). The solution is stirred at RT for 5 h. The solvent is concentrated to a half of the original volume, water is added and the reaction mixture is allowed to cool over ice. The solid that precipitates is collected by filtration and purified by crystallization to afford 4-chloro-5-methyl-1H-pyrazole-3-carboxylic acid ethyl ester as a white solid: m.p. 106-107° C.; 1H-NMR (DMSO-d6) δ 1.25-1.32 (t, 3H J=7 Hz), 2.21 (s, 3H), 4.22-4.32 (q, 2H J=7.2), 13.59 (s, 1H).

Workup

  1. concentrationThe solvent is concentrated to a half of the original volume, water
  2. additionis added
  3. temperatureto cool over ice
  4. customThe solid that precipitates
  5. filtrationis collected by filtration
  6. custompurified by crystallization

Sources & evidence

ORD record
ord-f4a432f52cb142898fb8ff753632850d
Source dataset
uspto-grants-2010_08
Patent number
US07767685B2

Reaction notes

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