3,4-Dimethyl-5-pyrazolone

Also known as: 3,4-Dimethyl-4,5-dihydro-1H-pyrazol-5-one, 4,5-Dimethyl-3H-pyrazol-3-one, 2,4-Dihydro-4,5-dimethyl-3H-pyrazol-3-one, 3,4-Dimethyl-2-pyrazolin-5-one, 3,4-Dimethyl-1,4-dihydropyrazol-5-one, 3,4-Dimethylpyrazolin-5-one, 4,5-Dimethyl-1,2-dihydro-pyrazol-3-one

3,4-Dimethyl-5-pyrazolone (CAS 6628-22-4) is a compound in the Pharma Intermediates category listed in the Jingsj chemical database. It has the molecular formula C5H8N2O and a molecular weight of 112.13000 g/mol. Key properties include a melting point of 269-271ºC, a boiling point of 307.5ºC at 760 mmHg, a density of 1.25g/cm3 and a flash point of 139.7ºC. No supplier offers are currently listed; request a quote. Record last updated Aug 21, 2026.

CAS No.: 6628-22-4
Jingsj CID: J-1442037-2
Molecular Formula: C₅H₈N₂O
Molecular Weight: 112.13000 g/mol
Category: Pharma Intermediates
Last updated: 8/21/2026

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Physicochemical Properties

Melting Point	269-271ºC
Boiling Point	307.5ºC at 760 mmHg
Density	1.25g/cm3
Flash Point	139.7ºC
Exact Mass	112.06400
PSA	41.46000
Refractive Index	1.579

Customs & Trade Information

HS Code	2933199090
Summary	2933199090. other compounds containing an unfused pyrazole ring (whether or not hydrogenated) in the structure. VAT:17.0%. Tax rebate rate:13.0%. . MFN tariff:6.5%. General tariff:20.0%

Frequently Asked Questions

What is the CAS number of 3,4-Dimethyl-5-pyrazolone?

The CAS number of 3,4-Dimethyl-5-pyrazolone is 6628-22-4.

What are the molecular formula and molecular weight of 3,4-Dimethyl-5-pyrazolone?

3,4-Dimethyl-5-pyrazolone has molecular formula C5H8N2O and molecular weight 112.13000 g/mol.

What are the upstream and downstream products of 3,4-Dimethyl-5-pyrazolone?

For 3,4-Dimethyl-5-pyrazolone, Upstream Products: Ethyl 2-methylacetoacetate, syn-(Methyl,methyl)bimane, methyl 2-methylacetoacetate; Downstream Products: Monobromobimane, Dibromobimane, syn-(Methyl,methyl)bimane.

Data compiled from public chemical databases such as PubChem and supplier catalogs; supplier offers are provided by suppliers.

Last updated: 8/21/2026

How to cite: Jingsj. "3,4-Dimethyl-5-pyrazolone (CAS 6628-22-4)". Jingsj Chemical Database. https://www.jingsj.com/compound/J-1442037-2 (accessed 2026-11-09).

Data for reference only; verify product details with suppliers before purchase.