Clemizole

Also known as: 1-(4-Chlorobenzyl)-2-(1-pyrrolidinylmethyl)-1H-benzimidazole, 1-(4-Chlorobenzyl)-2-(pyrrolidin-1-ylmethyl)-1H-benzimidazole, 1-(p-Chlorobenzyl)-2-(1-pyrrolidinylmethyl)benzimidazole, 1-[(4-Chlorophenyl)methyl]-2-(1-pyrrolidinylmethyl)-1H-benzimidazole, Allercur, Histacur, Histacuran, Histakool, Klemidox, Reactrol, Clemizolum

Clemizole (CAS 442-52-4) is a compound in the Pharma Intermediates category listed in the Jingsj chemical database. It has the molecular formula C19H20ClN3 and a molecular weight of 325.84300 g/mol. Key properties include a boiling point of 506.1±40.0 °C at 760 mmHg, a density of 1.3±0.1 g/cm3 and a flash point of 259.9±27.3 °C. No supplier offers are currently listed; request a quote. Record last updated Nov 4, 2026.

CAS No.: 442-52-4
Jingsj CID: J-17952-2
Molecular Formula: C₁₉H₂₀ClN₃
Molecular Weight: 325.84300 g/mol
Category: Pharma Intermediates
Last updated: 11/4/2026

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Physicochemical Properties

Boiling Point	506.1±40.0 °C at 760 mmHg
Density	1.3±0.1 g/cm3
Flash Point	259.9±27.3 °C
Exact Mass	325.134583
PSA	21.06000
LogP	5.10
Vapor Pressure	0.0±1.3 mmHg at 25°C
Refractive Index	1.656
Storage Conditions	-20°C

Activity & Biological Data

Target	IC50: 24 nM (NS4B)[1] H1 histamine receptor[1]
Additional Information	[1]. Einav S, et al. Discovery of a hepatitis C target and its pharmacological inhibitors by microfluidic affinity analysis. Nat Biotechnol. 2008 Sep;26(9):1019-27. [2]. Richter JM, et al. Clemizole hydrochloride is a novel and potent inhibitor of transient receptor potential channel TRPC5. Mol Pharmacol. 2014 Nov;86(5):514-21. [3]. Nishimura T, et al. Using chimeric mice with humanized livers to predict human drug metabolism and a drug-drug interaction. J Pharmacol Exp Ther. 2013 Feb;344(2):388-96.

Target

IC50: 24 nM (NS4B)[1] H1 histamine receptor[1]

Additional Information

[1]. Einav S, et al. Discovery of a hepatitis C target and its pharmacological inhibitors by microfluidic affinity analysis. Nat Biotechnol. 2008 Sep;26(9):1019-27. [2]. Richter JM, et al. Clemizole hydrochloride is a novel and potent inhibitor of transient receptor potential channel TRPC5. Mol Pharmacol. 2014 Nov;86(5):514-21. [3]. Nishimura T, et al. Using chimeric mice with humanized livers to predict human drug metabolism and a drug-drug interaction. J Pharmacol Exp Ther. 2013 Feb;344(2):388-96.

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 Clemizole?

The CAS number of Clemizole is 442-52-4.

What are the molecular formula and molecular weight of Clemizole?

Clemizole has molecular formula C19H20ClN3 and molecular weight 325.84300 g/mol.

What are the upstream and downstream products of Clemizole?

For Clemizole, Upstream Products: Pyrrolidine, 4-Chlorobenzyl bromide, 2-(Chloromethyl)benzimidazole.

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

Last updated: 11/4/2026

How to cite: Jingsj. "Clemizole (CAS 442-52-4)". Jingsj Chemical Database. https://www.jingsj.com/compound/J-17952-2 (accessed 2026-11-09).

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