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Cytosine

Also known as: 4-amino-2-hydroxypyrimidine, 4-amino-2(1H)-pyrimidinone, 2(1H)-Pyrimidinone, 4-amino-, 4-amino-2-oxo-1,2-dihydropyrimidine, 4-aminopyrimidin-2-one, Cyt, Cytosinimine

Cytosine (CAS 71-30-7) is a compound in the Pharma Intermediates category listed in the Jingsj chemical database. It has the molecular formula C4H5N3O and a molecular weight of 111.102 g/mol. Key properties include a melting point of >300 °C(lit.), a boiling point of 445.8ºC at 760 mmHg, a density of 1.6±0.1 g/cm3 and a flash point of 223.4ºC. It is classified under GHS with signal word Warning and hazard statements H315 — Causes skin irritation, H319 — Causes serious eye irritation and H335 — May cause respiratory irritation. No supplier offers are currently listed; request a quote. Record last updated Nov 3, 2026.

CAS No.
71-30-7
Jingsj CID
J-47622-1
Molecular Formula
C4H5N3O
Molecular Weight
111.102 g/mol
Category
Pharma Intermediates
Last updated
11/3/2026

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Physicochemical Properties

Melting Point>300 °C(lit.)
Boiling Point445.8ºC at 760 mmHg
Density1.6±0.1 g/cm3
Flash Point223.4ºC
Exact Mass111.043259
PSA71.77000
LogP-2.29
Refractive Index1.689
StabilityStable. Incompatible with strong oxidizing agents.
Additional Propertysoluble

GHS Safety & Compliance

IrritantSignal word: Warning
  • H315 — Causes skin irritation
  • H319 — Causes serious eye irritation
  • H335 — May cause respiratory irritation

Activity & Biological Data

TargetHuman Endogenous Metabolite

Customs & Trade Information

HS Code2933591000
SummaryHS:2933591000 4-aminopyrimidin-2(1h)-one VAT:17.0% Tax rebate rate:9.0% Supervision conditions:none MFN tariff:6.5% General tariff:20.0%

Frequently Asked Questions

What is the CAS number of Cytosine?

The CAS number of Cytosine is 71-30-7.

What are the molecular formula and molecular weight of Cytosine?

Cytosine has molecular formula C4H5N3O and molecular weight 111.102 g/mol.

Is Cytosine hazardous?

Cytosine has GHS signal word Warning and hazard statements H315 — Causes skin irritation; H319 — Causes serious eye irritation; H335 — May cause respiratory irritation.

What are the upstream and downstream products of Cytosine?

For Cytosine, Upstream Products: 3,3-Diethoxypropanenitrile, (E)-3-Ethoxyacrylonitrile, 2'-Deoxycytidine; Downstream Products: Dichloroacetonitrile, N-(Trimethylsilyl)-2-[(trimethylsilyl)oxy]pyrimidin-4-amine, Dihydrouracil.

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

Last updated:

How to cite: Jingsj. "Cytosine (CAS 71-30-7)". Jingsj Chemical Database. https://www.jingsj.com/compound/J-47622-1 (accessed 2026-11-06).

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