ChemicalBook > CAS DataBase List > 3H-PYRAZOL-3-ONE, 1,2-DIHYDRO-

3H-PYRAZOL-3-ONE, 1,2-DIHYDRO-

Uses

Product Name: 3H-PYRAZOL-3-ONE, 1,2-DIHYDRO-
CAS No.: 137-45-1
Chemical Name: 3H-PYRAZOL-3-ONE, 1,2-DIHYDRO-
Synonyms: 1,2-Dihydro-3H-pyrazol-3-one;NSC 520837;Pyrazol-3-ol;Pyrazol-5-ol;3-Pyrazolone;3H-pyrazol-3-one;1H-Pyrazol-3-one;4-Pyrazolin-3-one;3-Hydroxypyrazole;1,2-dihydropyrazol-3-on
CBNumber: CB7838723
Molecular Formula: C3H4N2O
Formula Weight: 84.08
MOL File: 137-45-1.mol

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3H-PYRAZOL-3-ONE, 1,2-DIHYDRO- Property

Melting point:: 160-162 °C
Density: 1.191±0.06 g/cm3(Predicted)
storage temp.: 2-8°C
pka: 9.00±0.70(Predicted)
form: solid
color: Pale yellow
InChI: InChI=1S/C3H4N2O/c6-3-1-2-4-5-3/h1-2H,(H2,4,5,6)
InChIKey: XBYRMPXUBGMOJC-UHFFFAOYSA-N
SMILES: N1C=CC(=O)N1

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Safety

HS Code: 2933199090

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Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Warning

Hazard statements

H302Harmful if swallowed

H315Causes skin irritation

H319Causes serious eye irritation

H332Harmful if inhaled

H335May cause respiratory irritation

Precautionary statements

P261Avoid breathing dust/fume/gas/mist/vapours/spray.

P280Wear protective gloves/protective clothing/eye protection/face protection.

P305+P351+P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.

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N-Bromosuccinimide Price

TCI Chemical

Product number: D5840
Product name: 1,2-Dihydro-3H-pyrazol-3-one
Purity: min. 98.0 %
Packaging: 1G
Price: $101
Updated: 2025/07/31

TCI Chemical

Product number: D5840
Product name: 1,2-Dihydro-3H-pyrazol-3-one
Purity: min. 98.0 %
Packaging: 5G
Price: $399
Updated: 2025/07/31

TRC

Product number: P840460
Product name: 1H-Pyrazol-3(2H)-one
Packaging: 10mg
Price: $45
Updated: 2021/12/16

Apolloscientific

Product number: OR300636
Product name: 5-Hydroxy-1H-pyrazole
Purity: 97%
Packaging: 1g
Price: $34
Updated: 2021/12/16

SynQuest Laboratories

Product number: 4H01-1-5Y
Product name: 5-Hydroxy-1H-pyrazole
Packaging: 1g
Price: $37
Updated: 2021/12/16

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3H-PYRAZOL-3-ONE, 1,2-DIHYDRO- Chemical Properties,Usage,Production

Uses

1,2-Dihydro-3H-pyrazole-3-one, also known as 1H-pyrazole-3(2H)-one, is an organic intermediate that can be prepared by one-step cyclization from methyl propargylate, ethyl acrylate, or (2E)-3-methoxyacrylate.

Synthesis

922-67-8

137-45-1

General procedure for the synthesis of 1,2-dihydro-3H-pyrazol-3-one from methyl propargylate: Hydrazine hydrate (3.62 mL, 48.53 mmol) was slowly added dropwise to a solution of methyl propargylate (4.23 mL, 47.58 mmol) dissolved in methanol (40 mL) under cooling conditions in an ice bath. The reaction mixture was stirred at room temperature for 30 min. Subsequently, brine (10 mL) was added and methanol was removed by distillation under reduced pressure. The remaining aqueous layer was extracted with ethyl acetate (4 × 75 mL), the organic layers were combined, dried with anhydrous magnesium sulfate, filtered and concentrated under reduced pressure to give 1,2-dihydro-3H-pyrazol-3-one (3.82 g, 95% yield) as a milky white solid. Nuclear magnetic resonance hydrogen spectrum (400 MHz, DMSO-d6): δ 5.44 (1H, d, J = 2.27 Hz), 7.35 (1H, d, J = 2.23 Hz), 9.50 (1H, br s, NH), 11.45 (1H, br s, NH); nuclear magnetic resonance carbon spectrum (101 MHz, DMSO-d6): δ 89.25, 129.71, 160.73; MS (electrospray positive ionization mode): m/z 85.04 (100, [M+H]+); high-resolution MS (electrospray ionization): measured value of [M+H]+ 85.03951, calculated value of C3H5N2O 85.03964.

References

[1] Tetrahedron, 2012, vol. 68, # 27-28, p. 5434 - 5444
[2] Patent: US2016/376287, 2016, A1. Location in patent: Paragraph 0634
[3] Patent: WO2017/117708, 2017, A1. Location in patent: Paragraph 54

3H-PYRAZOL-3-ONE, 1,2-DIHYDRO- Preparation Products And Raw materials

Raw materials

Preparation Products

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3H-PYRAZOL-3-ONE, 1,2-DIHYDRO- Suppliers

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View Lastest Price from 3H-PYRAZOL-3-ONE, 1,2-DIHYDRO- manufacturers

Shaanxi Dideu Medichem Co. Ltd

Product: 3H-PYRAZOL-3-ONE, 1,2-DIHYDRO- 137-45-1
Price: US $0.00-0.00/KG
Min. Order: 1KG
Purity: 99.0%
Supply Ability: 1000KG
Release date: 2024-07-11

Career Henan Chemical Co

Product: 3H-PYRAZOL-3-ONE, 1,2-DIHYDRO- 137-45-1
Price: US $1.00/KG
Min. Order: 1KG
Purity: 99.0%
Supply Ability: 100kg
Release date: 2020-01-08

137-45-1, 3H-PYRAZOL-3-ONE, 1,2-DIHYDRO-Related Search:

Metamizole Sodium Monohydrate 4-BROMOANTIPYRINE 3-Methyl-3-pyrazolin-5-one Aminopyrine 4-Aminoantipyrine 4-ACETAMIDOANTIPYRINE Antipyrine DIANTIPYRYLMETHANE 2,3-DIMETHYL-1-(4-METHYLPHENYL)-3-PYRAZOLIN-5-ONE 4-ANTIPYRINECARBOXALDEHYDE 4-HYDROXYANTIPYRINE 2-CHLORO-N-(1,5-DIMETHYL-3-OXO-2-PHENYL-2,3-DIHYDRO-1H-PYRAZOL-4-YL)ACETAMIDE 4,4'-[methylenebis(methylimino)]bis[1,2-dihydro-1,5-dimethyl-2-phenyl-3H-pyrazol-3-one] ANTIPYRINECARBOXYLIC ACID ETHYL N-(4-ANTIPYRYL)CARBAMATE AKOS BBS-00001838 4-(2-CHLORO-ACETYL)-1,5-DIMETHYL-2-PHENYL-1,2-DIHYDRO-PYRAZOL-3-ONE 4-BENZYLIDENE AMINO ANTIPYRENE

1,2-dihydropyrazol-3-one

1,2-Dihydro-3H-pyrazol-3-one

1,2-dihydropyrazol-3-on

Pyrazol-5-ol

Pyrazol-3-ol

NSC 520837

4-Pyrazolin-3-one

3-Pyrazolone

3H-pyrazol-3-one

3H-PYRAZOL-3-ONE, 1,2-DIHYDRO-

1H-Pyrazol-3-one

3-Hydroxypyrazole

1H pyrazole-3 (2H) - ketone

137-45-1