Uses
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

China 103 Europe 1 India 2 Japan 1 Switzerland 1 United Kingdom 1 United States 10 Global 119
Achemica
Tel
--
Fax
--
Email
contact@achemica.com
Country
Switzerland
ProdList
6155
Advantage
50
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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