5-Fluorouracil (5-FU)

CAS NO. 51-21-8

Availability:

Quantity:



Inquire Add to Basket PDF Export

Product Description

Product Name	5-Fluorouracil (5-FU) (Synonyms: Fluorouracil; 5-Fluoro-1H-pyrimidine-2,4-dione; 5-Fluoro-2,4(1H,3H)-pyrimidinedione)
CAS NO.	51-21-8
Formula & Molecular Weight	C₄H₃FN₂O₂ (MW: 130.08) \| EC: 200-085-6 \| MDL: MFCD00006018
Chemical Structure
Product Type	Fluorinated pyrimidine / research and downstream synthesis material 5-Fluorouracil is a pharmacologically active compound. Research-grade, synthesis-grade and pharmaceutical API materials can therefore have substantially different requirements for manufacturing controls, impurity profiles, analytical testing and regulatory documentation. This page should not be interpreted as an API, pharmacopoeial or finished-drug supply claim.
Reference Properties	Appearance: White to almost white powder or crystalline solid Molecular Weight: 130.08 Melting Point: Approximately 283 °C with decomposition Water Solubility: Slightly soluble Storage: Keep tightly closed and follow the storage conditions stated in the applicable supplier TDS/SDS Reference research-grade properties are provided for substance identification only. Commercial specification and quality grade must be confirmed against the actual supplier documentation.
Available Specification	Specification on Request Because quality requirements differ significantly by intended use, Royalchem recommends confirming the following parameters before quotation: Assay and analytical method Related substances / impurity profile Loss on drying / moisture Residue on ignition Elemental or other impurity requirements Required quality and regulatory documentation Final specification is subject to the applicable supplier TDS and batch COA.
Applications	Fluorinated Pyrimidine Research:Used as a well-known fluorinated pyrimidine compound in biochemical, pharmacological and nucleic-acid metabolism research. Flucytosine Synthesis:Published historical and industrial routes have used 5-Fluorouracil as a starting material for the preparation of Flucytosine (5-Fluorocytosine). Fluoropyrimidine Chemistry:Can be used as a starting material or reference compound in research and process development involving selected fluorinated pyrimidine derivatives. Analytical / Research Applications:High-purity 5-FU is commercially available as a research chemical. Requirements for research grades should not be assumed to represent pharmaceutical API specifications.
Packaging, Storage & Shipping	Packaging:Package size and container type depend on grade, quantity and safety requirements and are confirmed with the commercial quotation. Storage:Keep containers tightly closed in the conditions specified by the actual supplier. Protect from unnecessary exposure and avoid generation of dust.

Sourcing 5-FU for Research or Fluorinated Pyrimidine Synthesis?

Royalchem reviews 5-Fluorouracil (5-FU, CAS 51-21-8)inquiries for B2B research, process-development and confirmed downstream chemical-synthesis applications. Please provide your intended use, required assay, impurity limits, analytical method, quantity and documentation requirements. Availability and supply will be evaluated against the actual supplier specification, COA, SDS and applicable commercial requirements.

5-Fluorouracil vs Flucytosine

Item	5-Fluorouracil	Flucytosine
Abbreviation	5-FU	5-FC
CAS	51-21-8	2022-85-7
Relationship	They are different chemical compounds and must not be treated as interchangeable. Published synthetic routes have used 5-FU as a starting material for the preparation of 5-FC.

Frequently Asked Questions

What is the correct chemical name of 5-FU?	The common name is 5-Fluorouracil. The IUPAC name is 5-fluoro-1H-pyrimidine-2,4-dione. Its CAS number is 51-21-8.
Is 5-Fluorouracil an API?	5-Fluorouracil is itself a pharmacologically active drug substance, but that does not mean every commercial product with CAS 51-21-8 qualifies as a pharmaceutical API. API supply requires the relevant manufacturing quality system, specification and regulatory documentation.
Does ≥99% assay mean USP or EP grade?	No. Assay alone does not establish pharmacopoeial compliance. USP or EP claims require compliance with the applicable monograph, analytical procedures and other quality requirements, supported by the appropriate documentation.
Can 5-FU be used to synthesize Flucytosine?	Yes. Published historical and industrial routes have used 5-Fluorouracil as a starting material for the synthesis of 5-Fluorocytosine / Flucytosine through multistep conversion.
Is 5-Fluorouracil the same as Flucytosine?	No. 5-Fluorouracil is CAS 51-21-8, while Flucytosine is CAS 2022-85-7. They are distinct fluorinated pyrimidine compounds.
Can Royalchem provide COA and SDS?	If a suitable current supply source is available, batch-specific COA, SDS and specification information can be reviewed for commercial inquiries. Customers should provide intended use, specification, quantity and documentation requirements before quotation.