2-Hydrazinoethanol → 5-Amino-1-(2-hydroxyethyl)-1H-pyrazole-4-carboxylic acid

HRID 1281176Notes

Reaction equation

HRID 1281176 reaction equation
[NH2:1][C:2]1[N:6]([CH2:7][CH2:8][OH:9])[N:5]=[CH:4][C:3]=1[C:10]([O:12]CC)=[O:11].C(OC(=O)C(=COCC)C#N)C.OCCNN>C(O)C>[NH2:1][C:2]1[N:6]([CH2:7][CH2:8][OH:9])[N:5]=[CH:4][C:3]=1[C:10]([OH:12])=[O:11]

Participants

5

Reactant 3

HCID 80172-HydrazinoethanolHCID 789432-Propenoic acid, 2-cyano-3-ethoxy-, ethyl esterHCID 429881Ethyl 5-amino-1-(2-hydroxyethyl)-1H-pyrazole-4-carboxylate

Product 1

HCID 3200535-Amino-1-(2-hydroxyethyl)-1H-pyrazole-4-carboxylic acid

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

Example 4 of U.S. Pat. No. 2,989,537 describes the preparation of 5-amino-4-ethoxycarbonyl-1-(2′-hydroxyethyl)-pyrazole by reacting ethyl(ethoxymethylene)-cyanoacetate with 2-hydroxyethylhydrazine in ethanol and distilling the product under vacuum at high temperature. The isolated solid product then is hydrolyzed by heating with 2N aqueous sodium hydroxide solution followed by acidification with 6N hydrochloric acid to give 5-amino-4-carboxy-1-(2′-hydroxyethyl)-pyrazole. This hydrolysis procedure in water leaves some undissolved material that must be removed by filtration. The carboxy intermediate is, heated at 160-170° C. to complete the decarboxylation and the 5-amino-1-(2′-hydroxyethyl)-pyrazole is purified by distillation under vacuum at high temperature.

Workup

  1. distillationdistilling the product under vacuum at high temperature
  2. temperatureby heating with 2N aqueous sodium hydroxide solution

Sources & evidence

ORD record
ord-5e01e4d07a904af4b24c63a2a3bc4fdc
Source dataset
uspto-grants-2002_09
Patent number
US06452019B1

Reaction notes

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