Bromine → 3-(4-Bromo-pyrazol-1-yl)-4-methyl-benzoic acid ethyl ester

HRID 491850Notes

Reaction equation

HRID 491850 reaction equation
[CH2:1]([O:3][C:4](=[O:17])[C:5]1[CH:10]=[CH:9][C:8]([CH3:11])=[C:7]([N:12]2[CH:16]=[CH:15][CH:14]=[N:13]2)[CH:6]=1)[CH3:2].[Br:18]Br>C(Cl)(Cl)Cl>[CH2:1]([O:3][C:4](=[O:17])[C:5]1[CH:10]=[CH:9][C:8]([CH3:11])=[C:7]([N:12]2[CH:16]=[C:15]([Br:18])[CH:14]=[N:13]2)[CH:6]=1)[CH3:2]

Participants

4

Reactant 2

HCID 24408BromineHCID 588613364-Methyl-3-pyrazol-1-yl-benzoic acid ethyl ester

Product 1

HCID 588614423-(4-Bromo-pyrazol-1-yl)-4-methyl-benzoic acid ethyl esterYield 102.6%

Reagents, catalysts & solvents 1

HCID 6212ChloroformSolvent

Procedure

A solution of 3-hydrazino-4-methyl benzoic acid (1.0 g, 4.93 mmol), malonaldehyde(bismethylacetate) (0.82 mL, 4.93 mmol), and concentrated HCl (1 mL) in EtOH (20 mL) was heated to reflux for 4 h. After cooling to room temperature, the reaction was poured into ice water, neutralized with 2N NaOH, and extracted with CH2Cl2 (3×). The organic layers were dried over Na2SO4, filtered and concentrated to afford 4-methyl-3-pyrazol-1-yl-benzoic acid ethyl ester (536 mg, 47%) as a yellow oil. A solution of the pyrazole (536 mg, 2.33 mmol) and bromine (0.167 mL, 3.26 mmol) in CHCl3 (15 mL) was refluxed for 4.5 h then cooled to room temperature. The solvent was evaporated to an orange oil. Purification using chromatography on silica gel (1:1 EtOAc/hexanes) yielded 3-(4-bromo-pyrazol-1-yl)-4-methyl-benzoic acid ethyl ester (0.739 g, 99%) as a yellow solid.

Workup

  1. customThe solvent was evaporated to an orange oil
  2. customPurification

Sources & evidence

ORD record
ord-4b7d59e09c434d6bbef4f7c458658181
Source dataset
uspto-grants-2009_05
Patent number
US07531560B2

Reaction notes

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