Hydrochloric Acid → 5-chloro-1-phenyl-1H-pyrazole-4-carboxylic acid

HRID 1710338Notes

Reaction equation

HRID 1710338 reaction equation
C([O:3][C:4]([C:6]1[CH:7]=[N:8][N:9]([C:12]2[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=2)[C:10]=1[Cl:11])=[O:5])C.[OH-].[Li+].CO.Cl>O1CCCC1.O>[Cl:11][C:10]1[N:9]([C:12]2[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=2)[N:8]=[CH:7][C:6]=1[C:4]([OH:5])=[O:3]

Participants

7

Reactant 4

HCID 313Hydrochloric AcidHCID 887MethanolHCID 3939Lithium HydroxideHCID 13608341Ethyl 5-chloro-1-phenyl-1H-pyrazole-4-carboxylate2×

Product 1

HCID 71471255-chloro-1-phenyl-1H-pyrazole-4-carboxylic acidYield 91%

Reagents, catalysts & solvents 2

HCID 962WaterSolvent2×HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
70 °C

Procedure

To a solution of 5-chloro-1-phenyl-1H-pyrazole-4-carboxylic acid ethyl ester (Intermediate 1; 7.3 g, 29.1 mmol) in tetrahydrofuran (70 mL) was added a solution of lithium hydroxide in water (7.3 g, 305 mmol) in water (70 mL). Methanol (˜10 mL) was added dropwise to the reaction mixture until only one layer was visible. The reaction mixture was stirred at 70° C. for 1 hour (reaction progress monitored by TLC). The reaction mixture was acidified to pH 3 with 1N hydrochloric acid and washed with dichloromethane (3×200 mL). The organic layer was dried over magnesium sulfate and evaporated to give 5-chloro-1-phenyl-1H-pyrazole-4-carboxylic acid (5.8 g, 91%), which HPLC analysis indicated was 85% pure. This material was used directly in the next step without further purification.

Workup

  1. custom(reaction progress monitored by TLC)
  2. washwashed with dichloromethane (3×200 mL)
  3. dry with materialThe organic layer was dried over magnesium sulfate
  4. customevaporated

Sources & evidence

ORD record
ord-779eb53f8c4a4c94b31b981fb1fb4b7d
Source dataset
uspto-grants-2010_09
Patent number
US07790711B2

Reaction notes

Loading…