4-Chlorophthalazin-1(2H)-one

Also known as: 4-chloro-1,2-dihydrophthalazin-1-one, 1-chloro-4-phthalazinone, 1-chlorophthalazin-4-one, 1-chlorophtalazin-4-one, 4-chlor-2H-phthalazin-1-on, 4-chlorophthalazin-1(2H)-one, 4-chloro-1,2-dihydrophthalazinone, 4-chloro-1-phthalazinol, 4-chloro-2H-phthalazin-1-one, 4-chlorophthalazin-1-ol, AURORA KA-6768

4-Chlorophthalazin-1(2H)-one (CAS 2257-69-4) is a compound in the Ketones category listed in the Jingsj chemical database. It has the molecular formula C8H5ClN2O and a molecular weight of 180.59100 g/mol. Key properties include a melting point of 265ºC, a boiling point of 452.7ºC at 760mmHg, a density of 1.5g/cm3 and a flash point of 227.6ºC. No supplier offers are currently listed; request a quote. Record last updated Aug 21, 2026.

CAS No.: 2257-69-4
Jingsj CID: J-45132-1
Molecular Formula: C₈H₅ClN₂O
Molecular Weight: 180.59100 g/mol
Category: Ketones
Last updated: 8/21/2026

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Physicochemical Properties

Melting Point	265ºC
Boiling Point	452.7ºC at 760mmHg
Density	1.5g/cm3
Flash Point	227.6ºC
Exact Mass	180.00900
PSA	45.75000
LogP	1.57650
Vapor Pressure	8.2E-09mmHg at 25°C
Refractive Index	1.688

Customs & Trade Information

HS Code	2933990090
Summary	2933990090. heterocyclic compounds with nitrogen hetero-atom(s) only. 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 4-Chlorophthalazin-1(2H)-one?

The CAS number of 4-Chlorophthalazin-1(2H)-one is 2257-69-4.

What are the molecular formula and molecular weight of 4-Chlorophthalazin-1(2H)-one?

4-Chlorophthalazin-1(2H)-one has molecular formula C8H5ClN2O and molecular weight 180.59100 g/mol.

What are the upstream and downstream products of 4-Chlorophthalazin-1(2H)-one?

For 4-Chlorophthalazin-1(2H)-one, Upstream Products: 1,4-Dichlorophthalazine, Phthalic acid, Phthalic anhydride.

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. "4-Chlorophthalazin-1(2H)-one (CAS 2257-69-4)". Jingsj Chemical Database. https://www.jingsj.com/compound/J-45132-1 (accessed 2026-11-09).

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