Sodium Hydroxide → 3-bromo-1-(3-chloro-2-pyridinyl)-4,5-dihydro-1H-pyrazole-5-carboxylic acid

HRID 1513375Notes

Reaction equation

HRID 1513375 reaction equation
[Br:1][C:2]1[CH2:6][CH:5]([C:7]([O:9]CC)=[O:8])[N:4]([C:12]2[C:17]([Cl:18])=[CH:16][CH:15]=[CH:14][N:13]=2)[N:3]=1.[OH-].[Na+]>C(O)C>[Br:1][C:2]1[CH2:6][CH:5]([C:7]([OH:9])=[O:8])[N:4]([C:12]2[C:17]([Cl:18])=[CH:16][CH:15]=[CH:14][N:13]=2)[N:3]=1

Participants

4

Reactant 2

HCID 14798Sodium HydroxideHCID 100653831H-Pyrazole-5-carboxylic acid, 3-bromo-1-(3-chloro-2-pyridinyl)-4,5-dihydro-, ethyl ester

Product 1

HCID 596223433-bromo-1-(3-chloro-2-pyridinyl)-4,5-dihydro-1H-pyrazole-5-carboxylic acidYield 97.9%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

To a 500 mL flask, ethyl 3-bromo-1-(3-chloro-2-pyridinyl)-4,5-dihydro-1H-pyrazole-5-carboxylate (20 g, 93%, 55.92 mmol), ethanol (100 mL) were added. The solution of sodium hydroxide (2.34 g, 58.50 mmol, dissolved into water (100 mL)) was added dropwise. After being stirred for 2 hours at room temperature, the reaction mixture was concentrated by rotary evaporator to remove ethanol. Aqueous solution was extracted with ethyl acetate (30 mL) and acidified with concentrated hydrochloric acid to pH=3. Then aqueous solution was extracted with ethyl acetate (3×100 mL) again. The organic layers were washed with saturated brine (100 mL), dried over anhydrous magnesium sulfate and concentrated by rotary evaporator to give 3-bromo-1-(3-chloro-2-pyridinyl)-4,5-dihydro-1H-pyrazole-5-carboxylic acid (16.67 g) as a yellow solid in 92% yield. HPLC area normalization method content is 94% (Analytical condition: chromatographic column: ZORBAX Eclipse XDB-C84.6×150 mm 5 μm, mobile phase:the ratio of acetonitrile to water is 70:30).

Workup

  1. concentrationthe reaction mixture was concentrated by rotary evaporator
  2. customto remove ethanol
  3. extractionAqueous solution was extracted with ethyl acetate (30 mL)
  4. extractionThen aqueous solution was extracted with ethyl acetate (3×100 mL) again
  5. washThe organic layers were washed with saturated brine (100 mL)
  6. dry with materialdried over anhydrous magnesium sulfate
  7. concentrationconcentrated by rotary evaporator

Sources & evidence

ORD record
ord-f5500d545f9e4f8197304e43a167d885
Source dataset
uspto-grants-2012_07
Patent number
US08217179B2

Reaction notes

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