p-Toluenesulfonic acid monohydrate → Ethyl 1-(3-chloropyridin-2-yl)-5-hydroxy-3-(hydroxymethyl)-4,5-dihydro-1H-pyrazole-5-carboxylate

HRID 2044033Notes

Reaction equation

HRID 2044033 reaction equation
[NH2:1][C:2]([CH2:11][OH:12])=[CH:3][C:4](=[O:10])[C:5]([O:7][CH2:8][CH3:9])=[O:6].[Cl:13][C:14]1[C:15]([NH:20]N)=[N:16][CH:17]=[CH:18][CH:19]=1.O.C1(C)C=CC(S(O)(=O)=O)=CC=1>C(#N)C>[Cl:13][C:14]1[C:15]([N:20]2[C:4]([OH:10])([C:5]([O:7][CH2:8][CH3:9])=[O:6])[CH2:3][C:2]([CH2:11][OH:12])=[N:1]2)=[N:16][CH:17]=[CH:18][CH:19]=1

Participants

5

Reactant 3

HCID 521998p-Toluenesulfonic acid monohydrateHCID 5561003-Chloro-2-hydrazinylpyridineHCID 58320693Ethyl 4-amino-5-hydroxy-2-oxopent-3-enoate

Product 1

HCID 58320694Ethyl 1-(3-chloropyridin-2-yl)-5-hydroxy-3-(hydroxymethyl)-4,5-dihydro-1H-pyrazole-5-carboxylate

Reagents, catalysts & solvents 1

HCID 6342AcetonitrileSolvent

Procedure

A mixture of ethyl 4-amino-5-hydroxy-2-oxopent-3-enoate (2.5 g, 14 mmol), 3-chloropyridin-2-ylhydrazine (2.07 g, 14 mmol) and p-toluenesulphonic acid monohydrate (2.5 g, 13 mmol) was stirred in 25 ml of acetonitrile at 25° C. for 5 hours. The precipitate was isolated by filtration and the filtrate was concentrated under reduced pressure. The product was purified by column chromatography on SiO2 (eluent: hexane/ethyl acetate). Oil. Yield 4.2 g (90%).

Workup

  1. customThe precipitate was isolated by filtration
  2. concentrationthe filtrate was concentrated under reduced pressure
  3. customThe product was purified by column chromatography on SiO2 (eluent: hexane/ethyl acetate)

Sources & evidence

ORD record
ord-1822b89e83934b99897b357b2e281f04
Source dataset
uspto-grants-2013_11
Patent number
US08586753B2

Reaction notes

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