Sodium Hydroxide → 5-[2-(4-Chlorophenyl)-ethyl]1H-pyrazole-3-carboxylic acid

HRID 1434776Notes

Reaction equation

HRID 1434776 reaction equation
[OH-].[Na+].C([O:5][C:6]([C:8]1[CH:12]=[C:11]([CH2:13][CH2:14][C:15]2[CH:20]=[CH:19][C:18]([Cl:21])=[CH:17][CH:16]=2)[NH:10][N:9]=1)=[O:7])C>CO>[Cl:21][C:18]1[CH:19]=[CH:20][C:15]([CH2:14][CH2:13][C:11]2[NH:10][N:9]=[C:8]([C:6]([OH:7])=[O:5])[CH:12]=2)=[CH:16][CH:17]=1

Participants

4

Reactant 2

HCID 14798Sodium HydroxideHCID 574351015-[2-(4-Chlorophenyl)-ethyl]-1H-pyrazole-3-carboxylic acid ethyl ester

Product 1

HCID 118456555-[2-(4-Chlorophenyl)-ethyl]1H-pyrazole-3-carboxylic acidYield 92.3%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

Freshly prepared aq. NaOH (10 M in H2O, 16.31 mmol) was added to a stirring, room temperature solution of 68 (0.9092 g, 3.26 mmol) in MeOH (8.2 mL, 0.4 M) under N2. The reaction was then heated to reflux until the reaction was judged complete by HPLC (7 min). The reaction was concentrated, redissolved in H2O (5 mL), and extracted with EtOAc (2 mL). 10% aq. HCl was added dropwise to the aqueous layer until the pH=2. The white solid that precipitated was filtered off and washed with cold H2O. The solid was dried under vacuum overnight to obtain 0.7543 g (92.2%) of 69. Since 69 still contained a very small amount of an impurity, it was dissolved in 38 mL of toluene with 10 mL of EtOAc and 14 mL of EtOH while heating to reflux. Pure white solid precipitated from the reaction after sitting overnight (0.4052 g). solid (Note: An undesired impurity has a retention time of 9.904 min by HPLC). 1H (CD3OD, 400 MHz): δ 7.24 (2H, d, J=8.3 Hz), 7.15 (2H, d, J=8.3 Hz), 6.54 (1H, s), 2.95 (4H, s) ppm. 13C (CD3OD, 100 MHz): δ 164.68, 148.23, 142.84, 140.91, 133.00, 131.08, 129.46, 107.59, 35.83, 28.78 ppm. DEPT (CD3OD, 100 MHz): CH2 carbons: 35.83, 28.78; CH carbons: 131.08, 129.46, 107.59 ppm. HPLC: 9.026 min.

Workup

  1. temperatureThe reaction was then heated
  2. temperatureto reflux until the reaction
  3. customwas judged complete by HPLC (7 min)
  4. concentrationThe reaction was concentrated
  5. dissolutionredissolved in H2O (5 mL)
  6. extractionextracted with EtOAc (2 mL)
  7. addition10% aq. HCl was added dropwise to the aqueous layer until the pH=2
  8. customThe white solid that precipitated
  9. filtrationwas filtered off
  10. washwashed with cold H2O
  11. customThe solid was dried under vacuum overnight

Sources & evidence

ORD record
ord-ac2430df0db1486497e33884e4a57989
Source dataset
uspto-grants-2009_11
Patent number
US07615572B2

Reaction notes

Loading…