Warfarin

Athanor · official

C₁₉H₁₆O₄ · 308.3 g/mol

IUPAC name: 4-hydroxy-3-(3-oxo-1-phenylbutyl)chromen-2-one

Also called Coumadin, Jantoven, anticoagulant

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Drawn from its SMILES with RDKit

DangerFatal if swallowed · Fatal in contact with skin · Fatal if inhaled · May damage the unborn child · Causes damage to organs through prolonged or repeated exposure · Toxic to aquatic life with long lasting effects

Names and identifiers

IUPAC name: 4-hydroxy-3-(3-oxo-1-phenylbutyl)chromen-2-one
Synonyms: Coumadin, Jantoven, anticoagulant
+ 38 more
Coumafene, Zoocoumarin, Coumafen, Brumolin, Coumefene, Dethmor, Kumader, Warfarine, Kumadu, Vampirinip II, Coumarins, Kypfarin, Rodafarin, Solfarin, Dethnel, Kumatox, Maveran, Ratron, Rosex, Temus W, Vampirinip iii, Athrombine-K, Frass-Ratron, Mar-Frin, Rattentraenke, Ratorex, Rattunal, Warfarat, CO-Rax, Rats-no-more, Tox-hid, Rat-Gard, Rat-Kill, Rat-Trol, Ratron G, Ratten-Koederrohr, Coumaphene, Rat-Mix
Molecular formula: C₁₉H₁₆O₄
Empirical formula: C₁₉H₁₆O₄
Molecular weight: 308.3 g/mol
Exact mass: 308.10486
CAS number: 81-81-2
PubChem CID: 54678486
Canonical SMILES: CC(=O)CC(C1=CC=CC=C1)C2=C(C3=CC=CC=C3OC2=O)O
Isomeric SMILES: CC(=O)CC(C1=CC=CC=C1)C2=C(C3=CC=CC=C3OC2=O)O
InChI: InChI=1S/C19H16O4/c1-12(20)11-15(13-7-3-2-4-8-13)17-18(21)14-9-5-6-10-16(14)23-19(17)22/h2-10,15,21H,11H2,1H3
InChIKey: PJVWKTKQMONHTI-UHFFFAOYSA-N
Molfile

Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.

Physical properties

TemperaturePressureDensity

Appearance: White powder[5]
6 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
– Warfarin is an odorless and colorless solid. Used as a rodenticide for Norway rats and for house mice. (EPA, 1998) [1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
– COLOURLESS-TO-WHITE POWDER. [2] ILO-WHO International Chemical Safety Cards (ICSCs)
– Colorless, odorless, crystalline powder or solid. [3] Occupational Safety and Health Administration (OSHA)
– Colorless, odorless, crystalline powder. [Note: Rodenticide.] [4] The National Institute for Occupational Safety and Health (NIOSH)
–shown White powder [5] Hazardous Substances Data Bank (HSDB)cites Crop Protection Handbook Volume 99, Meister Media Worldwide, Willoughby, OH 2013, p. 733
– The racemate forms colorless crystals [5] Hazardous Substances Data Bank (HSDB)cites MacBean C, ed; e-Pesticide Manual. 15th ed., ver. 5.1, Alton, UK; British Crop Protection Council. Warfarin (81-81-2) (2008-2010)
Odor: Odorless[5]
Melting point: 161 °C[2]
5 values
5 of 5 sources agree on it (most common value).
Value As written Source
161 °C 322 °F (EPA, 1998) [1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
161 °Cshown 161 °C [2] ILO-WHO International Chemical Safety Cards (ICSCs)
161 °C 322 °F [3] Occupational Safety and Health Administration (OSHA)
161 °C 161 °C [6] PAC Chemical Database, U.S. Department of Energy
161 °C 322 °F [4] The National Institute for Occupational Safety and Health (NIOSH)
Boiling point: 356 °C @760 [mmHg][6]
Density: Relative density (water = 1): 1.4[2]
Solubility in water: Solubility in water, g/100ml at 20 °C: 0.0017 (very poor)[2]
6 values
From ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative source here.
Value As written Source
– 0.002 % (NIOSH, 2024) [1] CAMEO Chemicals
– Solubility: 1 g in 1.5 mL water, 1.9 mL alcohol, >10,000 mL chloroform, >10,000 mL ether /Warfarin potassium/ [5] Hazardous Substances Data Bank (HSDB)cites Osol, A. (ed.). Remington's Pharmaceutical Sciences. 16th ed. Easton, Pennsylvania: Mack Publishing Co., 1980., p. 768
– In water, 17 mg/L at 20 °C [5] Hazardous Substances Data Bank (HSDB)cites MacBean C, ed; e-Pesticide Manual. 15th ed., ver. 5.1, Alton, UK; British Crop Protection Council. Warfarin (81-81-2) (2008-2010)
– In acetone 65, chloroform 56, dioxane 100 (all in g/L, 20 °C) [5] Hazardous Substances Data Bank (HSDB)cites MacBean C, ed; e-Pesticide Manual. 15th ed., ver. 5.1, Alton, UK; British Crop Protection Council. Warfarin (81-81-2) (2008-2010)
–shown Solubility in water, g/100ml at 20 °C: 0.0017 (very poor) [2] ILO-WHO International Chemical Safety Cards (ICSCs)
– 0.002% [4] The National Institute for Occupational Safety and Health (NIOSH)
log P: log Kow = 2.70[5]
2 values
Sources disagree; from Hazardous Substances Data Bank (HSDB), the most authoritative.
Value As written Source
–shown log Kow = 2.70 [5] Hazardous Substances Data Bank (HSDB)cites Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 161
– 2.6 [2] ILO-WHO International Chemical Safety Cards (ICSCs)
pKa: pKa = 5.87[5]
Vapor pressure: 0.09 mmHg at 22 °C (71 °F, NIOSH 2024)[1]
3 values
2 of 3 sources agree on it (most common value).
Value As written Source
0.09 mmHgshown 0.09 mmHg at 71 °F (NIOSH, 2024) [1] CAMEO Chemicals
0.09 mmHg 0.09 mmHg at 71 °F [3] Occupational Safety and Health Administration (OSHA)
0.00001 mmHg 0.00001 [mm Hg] @25 °C [6] PAC Chemical Database, U.S. Department of Energy
3 more values were reported but failed the checks (unreadable or out of range), so they are not shown.

Value	As written	Source
–	Warfarin is an odorless and colorless solid. Used as a rodenticide for Norway rats and for house mice. (EPA, 1998)	[1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
–	COLOURLESS-TO-WHITE POWDER.	[2] ILO-WHO International Chemical Safety Cards (ICSCs)
–	Colorless, odorless, crystalline powder or solid.	[3] Occupational Safety and Health Administration (OSHA)
–	Colorless, odorless, crystalline powder. [Note: Rodenticide.]	[4] The National Institute for Occupational Safety and Health (NIOSH)
–shown	White powder	[5] Hazardous Substances Data Bank (HSDB)cites Crop Protection Handbook Volume 99, Meister Media Worldwide, Willoughby, OH 2013, p. 733
–	The racemate forms colorless crystals	[5] Hazardous Substances Data Bank (HSDB)cites MacBean C, ed; e-Pesticide Manual. 15th ed., ver. 5.1, Alton, UK; British Crop Protection Council. Warfarin (81-81-2) (2008-2010)

Value	As written	Source
161 °C	322 °F (EPA, 1998)	[1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
161 °Cshown	161 °C	[2] ILO-WHO International Chemical Safety Cards (ICSCs)
161 °C	322 °F	[3] Occupational Safety and Health Administration (OSHA)
161 °C	161 °C	[6] PAC Chemical Database, U.S. Department of Energy
161 °C	322 °F	[4] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
–	0.002 % (NIOSH, 2024)	[1] CAMEO Chemicals
–	Solubility: 1 g in 1.5 mL water, 1.9 mL alcohol, >10,000 mL chloroform, >10,000 mL ether /Warfarin potassium/	[5] Hazardous Substances Data Bank (HSDB)cites Osol, A. (ed.). Remington's Pharmaceutical Sciences. 16th ed. Easton, Pennsylvania: Mack Publishing Co., 1980., p. 768
–	In water, 17 mg/L at 20 °C	[5] Hazardous Substances Data Bank (HSDB)cites MacBean C, ed; e-Pesticide Manual. 15th ed., ver. 5.1, Alton, UK; British Crop Protection Council. Warfarin (81-81-2) (2008-2010)
–	In acetone 65, chloroform 56, dioxane 100 (all in g/L, 20 °C)	[5] Hazardous Substances Data Bank (HSDB)cites MacBean C, ed; e-Pesticide Manual. 15th ed., ver. 5.1, Alton, UK; British Crop Protection Council. Warfarin (81-81-2) (2008-2010)
–shown	Solubility in water, g/100ml at 20 °C: 0.0017 (very poor)	[2] ILO-WHO International Chemical Safety Cards (ICSCs)
–	0.002%	[4] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
–shown	log Kow = 2.70	[5] Hazardous Substances Data Bank (HSDB)cites Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 161
–	2.6	[2] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
0.09 mmHgshown	0.09 mmHg at 71 °F (NIOSH, 2024)	[1] CAMEO Chemicals
0.09 mmHg	0.09 mmHg at 71 °F	[3] Occupational Safety and Health Administration (OSHA)
0.00001 mmHg	0.00001 [mm Hg] @25 °C	[6] PAC Chemical Database, U.S. Department of Energy

Each value as its source reports it, with the source's number after it (listed under References). Where several sources report a property, the row shows the value most of them agree on, the rule the app uses; open the values to see every one.

Calculated

Heavy atoms: 23
Rings: 3
Aromatic rings: 3
Fraction sp³ carbons (Fsp3): 0.16
H-bond donors: 1
H-bond acceptors: 4
Rotatable bonds: 4
TPSA (Å²): 67.5 computed here · PubChem 63.6
Formal charge: 0
XLogP3: 2.7 PubChem
Complexity: 501 PubChem
Stereocenters: 0 defined, 1 undefinedCIP: C5: undefined
Double-bond geometry: None specified
Point group: C1 of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)

Elemental analysis

C74.01%
H5.23%
O20.76%

Isotope pattern

Each peak is a nominal mass with its abundance-weighted exact mass, as a percentage of the tallest, from IUPAC natural isotope abundances.

Computed from the structure with RDKit 2026.09 when this page was built, beside PubChem's own computed values from its record; where the two differ, both are shown.

Predicted

log P: 3.61 Crippen (Wildman and Crippen 1999)
log S (water solubility): -4.28 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 2.63 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 308.33
log P ≤ 5 (Crippen): 3.61
H-bond donors ≤ 5: 1
H-bond acceptors ≤ 10: 4

Passes all four rules.

¹³C NMR shifts, predicted

Predictions, not measurements; each names its method. A measured log P, where a source reports one, is under Physical properties.

Safety

Danger

Harmonized EU classification (CLP Annex VI). Source [7].

Acute toxicity
Health hazard
Environmental hazard

H300Fatal if swallowed
H310Fatal in contact with skin
H330Fatal if inhaled
H360DMay damage the unborn child
H372Causes damage to organs through prolonged or repeated exposure
H411Toxic to aquatic life with long lasting effects

Precautionary statements: P203, P260, P262, P264, P270, P271, P273, P280, P284, P301+P316, P302+P352, P304+P340, P316, P318, P319, P320, P321, P330, P361+P364, P391, P403+P233, P405, P501

View all classifications (2)

[7] Regulation (EC) No 1272/2008 of the European Parliament and of the Council · DangerH300, H310, H330, H360D, H372, H411
[8] European Chemicals Agency (ECHA) · 201 reports · DangerH300, H310, H312, H319, H330, H360, H372, H411, H412

Exposure limits

PEL-TWA (8-Hour Time Weighted Average): 0.1 mg/m³[3]
PEL: TWA 0.1 mg/m3[4]
TLV: (inhalable fraction): 0.01 mg/m[2]
TLV-TWA (Time Weighted Average): 0.01 mg/m³ (inhalable particulate matter) [2015][3]
IDLH: 100 mg/m3 (NIOSH, 2024)[1]
IDLH: 100 mg/cu m[5]

First aid

Signs and Symptoms of Warfarin Exposure: Warfarin is an anticoagulant. Hemorrhage is the most common sign and may be manifested by hemorrhagic skin rashes and lip, nose, and upper airway bleeding. Upper airway pain, difficulty in speaking and swallowing, and dyspnea (shortness of breath) may occur. Vomiting, abdominal pain, and bloody stools are common. Back pain may be noted. Emergency Life-Support Procedures: Acute exposure to warfarin may require decontamination and life support for the victims.[1]
(General first aid procedures) Eye: Irrigate immediately - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately. Skin: Soap wash promptly - If this chemical contacts the skin, promptly wash the contaminated skin with soap and water. If this chemical penetrates the clothing, promptly remove the clothing and wash the skin with soap and water.[4]
Refer for medical attention.[2]
Remove contaminated clothes. Rinse and then wash skin with water and soap. Refer immediately for medical attention .[2]

Storage

Separated from strong oxidants and food and feedstuffs. Well closed. Store in an area without drain or sewer access.[2]
Warfarin (therapeutic) prepn should be stored at a temp less than 40 °C, preferably between 15-30 °C; warfarin potassium & warfarin sodium tablets should be stored in tight, light-resistant containers & warfarin sodium powder for injection should be protected from light. Reconstituted solutions of warfarin sodium should be used immediately. (warfarin potassium & warfarin sodium)[5]
Do not store near feed and food. ... Store away from heat and open flames.[5]

Incompatibilities

Strong oxidizers.[5]
Warfarin sodium is physically incompatible with ammonium chloride, ... Epinephrine HCl, metaraminol bitartrate, oxytocin, promazine HCl, & vancomycin HCl. (from table)[5]
Strong oxidizers[4]

Safety data sheets on the supplier’s page: Enamine, Hunan Huateng Pharmaceutical Co., Ltd., AA BLOCKS.

Always read the supplier’s safety data sheet before working with it.

Spectra

Experimental spectra held by these sources; each link opens the source's own record.

Literature

Reading PubChem, OpenAlex and GSRS…

Bioactivity

Reading ChEMBL…

References

[1]CAMEO Chemicals · Public domain (NOAA) · via PubChem · retrieved 2026-10-14
[2]ILO-WHO International Chemical Safety Cards (ICSCs) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[3]Occupational Safety and Health Administration (OSHA) · Public domain (US DOL) · via PubChem · retrieved 2026-10-14
[4]The National Institute for Occupational Safety and Health (NIOSH) · Public domain (US CDC) · via PubChem · retrieved 2026-10-14
[5]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
[6]PAC Chemical Database, U.S. Department of Energy · Public domain (US DOE) · via PubChem · retrieved 2026-10-14
[7]Regulation (EC) No 1272/2008 of the European Parliament and of the Council · EU reuse policy, CC BY 4.0 · via PubChem · retrieved 2026-10-14
[8]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
[9]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
[10]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
[11]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[12]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
[13]MassBank Europe · Linked only · via PubChem · retrieved 2026-10-14
·Calculated values: computed by Athanor with RDKit 2026.09 from the structure.
·Literature on PubChem

Data last updated 2026-10-14.