Hydrazine → Ethyl 3-oxo-3H-pyrazole-5-carboxylate

HRID 1668263Notes

Reaction equation

[C:1]([C:4]1[NH:5][NH:6][C:7](=[O:9])[CH:8]=1)([OH:3])=[O:2].[C:10](OCC)(=O)[CH2:11]C(C(OCC)=O)=O.NN>>[C:1]([C:4]1[N:5]=[N:6][C:7](=[O:9])[CH:8]=1)([O:3][CH2:10][CH3:11])=[O:2]

Participants

Reactant 3

HCID 9321Hydrazine

HCID 66951Diethyl oxalacetate

HCID 30846762,5-Dihydro-5-oxo-1H-pyrazole-3-carboxylic acid

Product 1

HCID 19858287Ethyl 3-oxo-3H-pyrazole-5-carboxylate

Procedure

3-carboxy-1H-pyrazol-5-one, for example, can thus be prepared by reacting diethyl oxalacetate with hydrazine to yield 3-(carboethoxy)-pyrazol-5-one, followed by refluxing in aqueous HCl solution to hydrolyze the ethyl ester.

Sources & evidence

ORD record: ord-0de7c4e7f1254c798623acd97ef71758
Source dataset: uspto-grants-2011_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07988740B2

Reaction notes

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