1-Methyl-1H-pyrazol-3(2H)-one

1-Methyl-1H-pyrazol-3(2H)-one Property

Melting point:

124-128°C

Density 

1.146±0.06 g/cm3(Predicted)

storage temp. 

Sealed in dry,Room Temperature

form 

solid

pka

8.98±0.70(Predicted)

Appearance

White to off-white Solid

InChI

InChI=1S/C4H6N2O/c1-6-3-2-4(7)5-6/h2-3H,1H3,(H,5,7)

InChIKey

WIISOYLZJJYTHT-UHFFFAOYSA-N

SMILES

N1(C)C=CC(=O)N1

Safety

Hazard Codes 

Xi

Risk Statements 

37/38-41

Safety Statements 

26-39

WGK Germany 

3

HS Code 

2933199090

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Danger

Hazard statements

H315Causes skin irritation

H318Causes serious eye damage

H335May cause respiratory irritation

Precautionary statements

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

P302+P352IF ON SKIN: wash with plenty of soap and water.

1-Methyl-1H-pyrazol-3(2H)-one Chemical Properties,Usage,Production

Synthesis

Example 7: General procedure for the synthesis of 1-methyl-1H-pyrazol-3(2H)-one from methyl 3-methoxyacrylate and monomethylhydrazine. In a 250 mL flask, 70 g of methanol and 60.5 g (0.46 mol) of 35% concentration of monomethylhydrazine aqueous solution were first added and the reaction temperature was kept at 25 °C. Subsequently, 47.8 g (0.40 mol) of methyl 3-methoxyacrylate was slowly added dropwise over 25 min. The pH of the reaction mixture was maintained at 12 by parallel dropwise addition of a 17% concentration of aqueous NaOH solution during the dropwise addition and during subsequent stirring for 6 h. A total of 97.5 g of NaOH solution was consumed for this process. The yield of the target product 1-methyl-1H-pyrazol-3(2H)-one was 75% when the reaction reached 100% conversion. The ratio of 3-hydroxy isomer to 5-hydroxy isomer in the product was ≥15:1.

References

[1] Patent: US6392058, 2002, B1