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Analgesics and anti-inflammatories

Phenylbutazone

Also known as 4-Butyl-1,2-diphenylpyrazolidine-3,5-dione, Butapirazol, Butadion

CAS 50-33-9Formula C19H20N2O2Molar mass 308.38 g/molEC 200-029-0
GHS signal word: Danger. Pictograms: Acute toxicity (severe), Harmful or irritant, Serious health hazard 116 suppliers listed Drug substance
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Phenylbutazone chemical structure, C19H20N2O2, CAS 50-33-9
2D chemical structure

Key facts

What buyers check first

All properties
Appearance
Crystals from ethanol
Melting point
105 °C
Solubility
Solubility in water at 22.5 °C: 0.7 mg/mL (also 2.2 mg/mL)
HS code
293319
Category
Analgesics and anti-inflammatories
UN number
UN 2811
Illustrative photo, closed blue fibre drums on a pallet in a warehouse
Typical packagingIllustrative packaging image, not the actual product

What is Phenylbutazone?

Plain description, key identifiers and synonyms

Phenylbutazone is a member of the class of pyrazolidines that is 1,2-diphenylpyrazolidine-3,5-dione carrying a butyl group at the 4-position. It has a role as a metabolite, a non-steroidal anti-inflammatory drug, a non-narcotic analgesic, an antirheumatic drug, a peripheral nervous system drug and an EC 1.1.1.184 [carbonyl reductase (NADPH)] inhibitor.

Identifiers

Registry numbers, names and line notations, tap to copy

IUPAC name
4-butyl-1,2-diphenylpyrazolidine-3,5-dione
CAS number
50-33-9 CAS number cross-checkedOther or deprecated CAS: 4297-92-1
EC number
200-029-0
Molecular formula
C19H20N2O2
UNII
GN5P7K3T8S
MDL number
MFCD00005500
InChIKey
VYMDGNCVAMGZFE-UHFFFAOYSA-N
InChI
InChI=1S/C19H20N2O2/c1-2-3-14-17-18(22)20(15-10-6-4-7-11-15)21(19(17)23)16-12-8-5-9-13-16/h4-13,17H,2-3,14H2,1H3
SMILES (canonical and isomeric)
CCCCC1C(=O)N(N(C1=O)C2=CC=CC=C2)C3=CC=CC=C3

Synonyms

  • 4-Butyl-1,2-diphenylpyrazolidine-3,5-dione
  • Butapirazol
  • Butadion
  • Butazolidin
  • Flexazone
  • Azolid
  • Butacote
  • Butazolidine
  • Ecobutazone
  • Fenibutazona
  • Fenilbutazona
  • Fenylbutazon
  • Intrabutazone
  • Artrizin
  • Butadiona
  • Diphebuzol
  • Fenibutol
  • Intrazone
  • Phebuzine
  • Butoz
  • Buzon
  • Diphenylbutazone
  • Equipalazone
  • Phenylbutazonum
  • Alkabutazona
Show all 39 synonyms
  • Alqoverin
  • Anuspiramin
  • Arthrizon
  • Artrizone
  • Bunetzone
  • Butacompren
  • Butagesic
  • Butalgina
  • Butalidon
  • Butapirazole
  • Butarecbon
  • Butartril
  • Butartrina
  • Butidiona

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

Appearance
Crystals from ethanolexp.
Odour
ODORLESSexp.
Taste
Slightly bitter tasteexp.
Melting point
105 °Cexp.
Solubility
Solubility in water at 22.5 °C: 0.7 mg/mL (also 2.2 mg/mL)exp.

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
308.38 g/molcalc.
Exact mass
308.1525 Dacalc.
LogP (octanol/water)
3.79calc.
Topological polar surface area
40.62 Ųcalc.
Hydrogen bond donors
0calc.
Hydrogen bond acceptors
2calc.
Rotatable bonds
5calc.
Heavy atoms
23calc.
Rings
3calc.
Aromatic rings
2calc.
Fraction sp3 carbons
0.26calc.
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=C1CC(=O)N(c2ccccc2)N1c1ccccc1

O=C1CC(=O)N(c2ccccc2)N1c1ccccc1

3 rings, 19 atoms, the 1,2-Diphenyl-3,5-pyrazolidinedione ring system.

92 other chemicals share this scaffold

Safety and hazards

GHS classification summary, not a safety data sheet

GHS signal word
Danger
GHS06: Acute toxicity (severe)
Acute toxicity (severe)
GHS07: Harmful or irritant
Harmful or irritant
GHS08: Serious health hazard
Serious health hazard

Hazard statements

  • H301Toxic if swallowed.
  • H312Harmful in contact with skin.
  • H315Causes skin irritation.
  • H317May cause an allergic skin reaction.
  • H319Causes serious eye irritation.
  • H332Harmful if inhaled.
  • H334May cause allergy or asthma symptoms or breathing difficulties if inhaled.
  • H335May cause respiratory irritation.
  • H351Suspected of causing cancer.
  • H361Suspected of damaging fertility or the unborn child.
Precautionary statements (29)
  • P203Obtain, read and follow all safety instructions before use.
  • P233Keep container tightly closed.
  • P260Do not breathe dust, fume, gas, mist, vapours or spray.
  • P261Avoid breathing dust, fume, gas, mist, vapours or spray.
  • P264Wash skin thoroughly after handling.
  • P264 + P265Wash skin thoroughly after handling. Do not touch eyes.
  • P270Do not eat, drink or smoke when using this product.
  • P271Use only outdoors or in a well-ventilated area.
  • P272Contaminated work clothing should not be allowed out of the workplace.
  • P280Wear protective gloves, protective clothing, eye protection and face protection.
  • P284In case of inadequate ventilation wear respiratory protection.
  • P301 + P316If swallowed: Get emergency medical help immediately.
  • P302 + P352If on skin: Wash with plenty of water.
  • P304 + P340If inhaled: Remove person to fresh air and keep comfortable for breathing.
  • P305 + P351 + P338If in eyes: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
  • P317Get medical help.
  • P318If exposed or concerned, get medical advice.
  • P319Get medical help if you feel unwell.
  • P321Specific treatment (see supplemental first aid instructions on the label).
  • P330Rinse mouth.
  • P332 + P317If skin irritation occurs: Get medical help.
  • P333 + P317If skin irritation or rash occurs: Get medical help.
  • P337 + P317If eye irritation persists: Get medical help.
  • P342 + P316If experiencing respiratory symptoms: Get emergency medical help immediately.
  • P362 + P364Take off contaminated clothing. And wash it before reuse.
  • P403Store in a well-ventilated place.
  • P403 + P233Store in a well-ventilated place. Keep container tightly closed.
  • P405Store locked up.
  • P501Dispose of contents and container in accordance with local regulations.
UN number
UN 2811

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

Phenylbutazone suppliers

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All 116 suppliers
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Where suppliers are based

116 suppliers in 18 countries

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Phenylbutazone price

Indicative price range per kg from live supplier offers

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Uses and applications

What the substance is used for, by industry and function

Analgesic in dogs, cats, horses, cattle, pigs.

Therapeutic category: Anti-inflammatory.

Therapeutic category (veterinary): Analgesic, anti-inflammatory.

Veterinary medication:.

Use classes: Pharmaceuticals, Animal Drugs.

Pharmacological actions

  • Anti-Inflammatory Agents, Non-Steroidal

Roles

  • analgesic
  • anti-inflammatory agent
  • anti-inflammatory drug
  • antirheumatic drug
  • enzyme inhibitor
  • metabolite
  • non-narcotic analgesic
  • non-steroidal anti-inflammatory drug
  • peripheral nervous system drug
  • pharmaceutical

How it is made

Derived from the condensation of 2-(n-butyl)malonate with 1,2-diphenylhydrazine

Heating diethyl-n-butylmalonate and 1,2-diphenylhydrazine in the presence of sodium ethoxide at 150 °C followed by acidification affords phenylbutazone in good yield. Alternatively, n-butylmalonyl chloride in pyridine and ether at 0 °C is treated with 1,2-diphenylhydrazine to give the desired product.

Reaction of butylmalonyl chloride with hydrazobenzene in ether solution, followed by extraction with sodium carbonate

Regulatory status

Inventories, regulations and trade controls that list this substance

Health and food

  • EU Cosmetics Regulation Annex II, prohibited in cosmetics
    Name: Phenylbutazone (INN), Ref no: 67, Annex ref: II/67
  • Active ingredient in FDA approved drug labels

United States

  • TSCA inventory (USA)
    Status: Active in US commerce

HS code and trade data

Customs classification and reported world trade statistics

Global trade

World import and export statistics for the HS code Phenylbutazone is traded under.

HS 2933.19Indicative HS code

Compounds containing an unfused pyrazole ring (whether or not hydrogenated) in the…

World exports in 2024
$3.44B
−22.6% vs 2023, imports $6.66B
2019 to 2024
Top exporters
  1. China21.6%
  2. Switzerland * partner reported20.5%
  3. Germany19.0%
Top importers
  1. Slovenia38.4%
  2. Portugal14.1%
  3. Brazil13.0%

* Partner reported figures, a lower bound.

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

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

Frequently asked questions

Quick answers about Phenylbutazone, based on the data on this page

What is Phenylbutazone?

Phenylbutazone is a member of the class of pyrazolidines that is 1,2-diphenylpyrazolidine-3,5-dione carrying a butyl group at the 4-position.

What is the CAS number of Phenylbutazone?

The CAS registry number of Phenylbutazone is 50-33-9. Other or deprecated CAS numbers: 4297-92-1.

What is the molecular formula and weight of Phenylbutazone?

The molecular formula of Phenylbutazone is C19H20N2O2 and its molar mass is 308.38 g/mol.

What is Phenylbutazone used for?

Analgesic in dogs, cats, horses, cattle, pigs. Therapeutic category: Anti-inflammatory. Therapeutic category (veterinary): Analgesic, anti-inflammatory. Veterinary medication:. Use classes: Pharmaceuticals, Animal Drugs.

Is Phenylbutazone hazardous?

Phenylbutazone carries the GHS signal word "Danger". Main hazards: toxic if swallowed, harmful in contact with skin, causes skin irritation. This summary is not an SDS, always read the supplier safety data sheet.

What is the HS code of Phenylbutazone?

Phenylbutazone is usually classified under HS code 293319 (Compounds containing an unfused pyrazole ring (whether or not hydrogenated) in the…). This is indicative, confirm it with your customs broker before shipping.

Where can I buy Phenylbutazone?

CompoundList lists 116 suppliers of Phenylbutazone in United States, China, India, United Kingdom and 14 more. Send one free request to get and compare quotes. Your contact details stay private until you accept a quote.

Where can I buy Phenylbutazone in India?

10 suppliers in India list Phenylbutazone on CompoundList. Filter the suppliers list by country and send a request to compare prices, grades and delivery times.

What is the price of Phenylbutazone?

Suppliers quote Phenylbutazone 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 Phenylbutazone

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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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