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Heterocyclic building blocks

4-Thiouracil

Also known as 4-sulfanylidene-1H-pyrimidin-2-one, 2-Hydroxy-4-mercaptopyrimidine, 4-mercaptopyrimidin-2-ol

CAS 591-28-6Formula C4H4N2OSMolar mass 128.16 g/molEC 627-565-1
GHS signal word: Warning. Pictograms: Harmful or irritant 7 suppliers listed
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4-Thiouracil chemical structure, C4H4N2OS, CAS 591-28-6
2D chemical structure

Key facts

What buyers check first

All properties
CAS number
591-28-6
Formula
C4H4N2OS
Molar mass
128.16 g/mol
EC number
627-565-1
HS code
293359
Category
Heterocyclic building blocks

What is 4-Thiouracil?

Plain description, key identifiers and synonyms

4-thiouracil is an organic molecular entity. It is functionally related to a uracil.

Identifiers

Registry numbers, names and line notations, tap to copy

IUPAC name
4-sulfanylidene-1H-pyrimidin-2-one
CAS number
591-28-6 CAS number cross-checkedOther or deprecated CAS: 203213-13-2, 203213-14-3, 203213-15-4, 203213-16-5, 203268-53-5
EC number
627-565-1
Molecular formula
C4H4N2OS
MDL number
MFCD00090842
InChIKey
OVONXEQGWXGFJD-UHFFFAOYSA-N
InChI
InChI=1S/C4H4N2OS/c7-4-5-2-1-3(8)6-4/h1-2H,(H2,5,6,7,8)
SMILES (canonical and isomeric)
C1=CNC(=O)NC1=S

Synonyms

  • 4-sulfanylidene-1H-pyrimidin-2-one
  • 2-Hydroxy-4-mercaptopyrimidine
  • 4-mercaptopyrimidin-2-ol
  • 2-Hydroxy-4-thiopyrimidine
  • Uracil, 4-thio-
  • 2(1H)-pyrimidinone, 3,4-dihydro-4-thioxo-
  • 2-Pyrimidinol, 4-mercapto- (9CI)
  • KC 135
  • 2-Hydroxypyrimidine-4(1H)-thione
  • 2-Pyrimidinol, 4-mercapto-
  • 4(3H)-Pyrimidinethione, 2-hydroxy-
  • 4-thiopyrimidin-2-one
  • 4-Thiouracil, 97%
  • 4-sulfanylpyrimidin-2-ol
  • 4-sulfanylidene-1,2,3,4-tetrahydropyrimidin-2-one
  • 6-sulfanyl-1H-pyrimidin-2-one
  • 2(1H)-Pyrimidinone, 4-mercapto-
  • 2(1H)-Pyrimidinone, 6-mercapto-
  • 4-sulfanylidene-1~{H}-pyrimidin-2-one
  • 4-thioxo-3,4-dihydro-2(1H)-pyrimidinone
  • 4-Sulfanylidene-3,4-dihydropyrimidin-2(1H)-one

Physical and chemical properties

Measured values and descriptors computed from the structure

Physical and chemical properties

Measured values, check the supplier specification for your grade

No measured properties are recorded for this substance yet. Ask suppliers for a technical data sheet.

Values vary by grade. Ask suppliers for the COA or TDS of the batch you buy.

Computed descriptors

Calculated from the structure, useful for screening and formulation

Molecular weight
128.16 g/molcalc.
Exact mass
128.0044 Dacalc.
LogP (octanol/water)
0.43calc.
Topological polar surface area
48.65 Ųcalc.
Hydrogen bond donors
2calc.
Hydrogen bond acceptors
2calc.
Rotatable bonds
0calc.
Heavy atoms
8calc.
Rings
1calc.
Aromatic rings
1calc.
Fraction sp3 carbons
0calc.
Formal charge
0calc.
Stereocentres
0calc.
Lipinski rule of five
Passes (0 violations)calc.

Calculated for screening. Confirm critical figures with the supplier.

Murcko scaffold

The ring system that remains when every side chain is removed

Murcko scaffold of this chemical, O=c1[nH]ccc(=S)[nH]1

O=c1[nH]ccc(=S)[nH]1

1 ring, 8 atoms. This chemical is the scaffold itself.

38 other chemicals share this scaffold

Safety and hazards

GHS classification summary, not a safety data sheet

GHS signal word
Warning
GHS07: Harmful or irritant
Harmful or irritant

Hazard statements

  • H302Harmful if swallowed.
  • H312Harmful in contact with skin.
  • H332Harmful if inhaled.
Precautionary statements (13)
  • P261Avoid breathing dust, fume, gas, mist, vapours or spray.
  • P264Wash skin thoroughly after handling.
  • P270Do not eat, drink or smoke when using this product.
  • P271Use only outdoors or in a well-ventilated area.
  • P280Wear protective gloves, protective clothing, eye protection and face protection.
  • P301 + P317If swallowed: Get medical help.
  • P302 + P352If on skin: Wash with plenty of water.
  • P304 + P340If inhaled: Remove person to fresh air and keep comfortable for breathing.
  • P317Get medical help.
  • P321Specific treatment (see supplemental first aid instructions on the label).
  • P330Rinse mouth.
  • P362 + P364Take off contaminated clothing. And wash it before reuse.
  • P501Dispose of contents and container in accordance with local regulations.

GHS classification summary, not a safety data sheet (SDS). Classifications can differ by supplier, grade and concentration. Always check the supplier's SDS.

Full safety data and first aid

4-Thiouracil suppliers

Sponsored listings first, then the documented ranking: membership, verification, replies, completeness, freshness and ratings

All 7 suppliers
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Where suppliers are based

7 suppliers in 5 countries

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4-Thiouracil price

Indicative price range per kg from live supplier offers

No published prices right now

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Uses and applications

What the substance is used for, by industry and function

Regulatory status

Inventories, regulations and trade controls that list this substance

No regulatory list memberships are recorded for this substance yet. Always check the rules of the importing and exporting country before trade.

HS code and trade data

Customs classification and reported world trade statistics

Global trade

World import and export statistics for the HS code 4-Thiouracil is traded under.

HS 2933.59Indicative HS code

Compounds containing a pyrimidine ring (whether or not hydrogenated) or piperazine ring, other

World exports in 2024
$18.4B
+10.5% vs 2023, imports $24.8B
2019 to 2024
Top exporters
  1. Ireland43.6%
  2. Switzerland * partner reported26.3%
  3. China7.9%
Top importers
  1. Slovenia30.3%
  2. United States30.1%
  3. Germany15.3%

* Partner reported figures, a lower bound.

Reported customs values in USD, not prices.Full trade data

The HS code shown for 4-Thiouracil is indicative (it was assigned by structure rules). Confirm the classification with your customs broker before shipping.

Frequently asked questions

Quick answers about 4-Thiouracil, based on the data on this page

What is 4-Thiouracil?

4-thiouracil is an organic molecular entity. It is functionally related to a uracil.

What is the CAS number of 4-Thiouracil?

The CAS registry number of 4-Thiouracil is 591-28-6. Other or deprecated CAS numbers: 203213-13-2, 203213-14-3, 203213-15-4.

What is the molecular formula and weight of 4-Thiouracil?

The molecular formula of 4-Thiouracil is C4H4N2OS and its molar mass is 128.16 g/mol.

What is 4-Thiouracil used for?

Known uses and roles of 4-Thiouracil include building blocks in research and laboratory and screening compounds in research and laboratory.

Is 4-Thiouracil hazardous?

4-Thiouracil carries the GHS signal word "Warning". Main hazards: harmful if swallowed, harmful in contact with skin, harmful if inhaled. This summary is not an SDS, always read the supplier safety data sheet.

What is the HS code of 4-Thiouracil?

4-Thiouracil is usually classified under HS code 293359 (Compounds containing a pyrimidine ring (whether or not hydrogenated) or piperazine ring…). This is indicative, confirm it with your customs broker before shipping.

Where can I buy 4-Thiouracil?

CompoundList lists 7 suppliers of 4-Thiouracil in China, Canada, Japan, Slovakia and 1 more. Send one free request to get and compare quotes. Your contact details stay private until you accept a quote.

What is the price of 4-Thiouracil?

Suppliers quote 4-Thiouracil on request because prices depend on grade, purity, quantity and destination. A free request on CompoundList gets you several quotes to compare.

Guides for buyers

Practical guides that help when you source, ship or handle 4-Thiouracil

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Data last updated 7 Oct 2026. Details may have changed, please confirm them with the supplier. Report an error on this page
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