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Herbicides

Pyrazoxyfen

Also known as Paicer, pyrazoxyfene, 2-(4-(2,4-Dichlorobenzoyl)-1,3-dimethylpyrazol-5-yloxy)acetophenone

CAS 71561-11-0Formula C20H16Cl2N2O3Molar mass 403.27 g/molEC 615-306-5
GHS signal word: Warning. Pictograms: Harmful or irritant, Hazardous to the environment
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Pyrazoxyfen chemical structure, C20H16Cl2N2O3, CAS 71561-11-0
2D chemical structure

Key facts

What buyers check first

All properties
CAS number
71561-11-0
Formula
C20H16Cl2N2O3
Molar mass
403.27 g/mol
EC number
615-306-5
HS code
293319
Category
Herbicides

What is Pyrazoxyfen?

Plain description, key identifiers and synonyms

Pyrazoxyfen is a member of the class of pyrazoles that is 1,3-dimethylpyrazole which is substituted at positions 4 and 5 by 2,4-dichlorobenzoyl and 2-oxo-2-phenylethoxy groups, respectively. A pro-herbicide (for the corresponding 5-hydroxypyrazole), it is used as a pre- or post-emergence herbicide for the control of annual and perennial weeds in rice. It has a role as a proherbicide, a carotenoid biosynthesis inhibitor and an agrochemical. It is a member of acetophenones, a dichlorobenzene and a member of pyrazoles.

Identifiers

Registry numbers, names and line notations, tap to copy

IUPAC name
2-[4-(2,4-dichlorobenzoyl)-1,3-dimethylpyrazol-5-yl]oxy-1-phenylethanone
CAS number
71561-11-0 CAS number cross-checked
EC number
615-306-5
Molecular formula
C20H16Cl2N2O3
UNII
FS6C1PT8FV
MDL number
MFCD00274563
InChIKey
FKERUJTUOYLBKB-UHFFFAOYSA-N
InChI
InChI=1S/C20H16Cl2N2O3/c1-12-18(19(26)15-9-8-14(21)10-16(15)22)20(24(2)23-12)27-11-17(25)13-6-4-3-5-7-13/h3-10H,11H2,1-2H3
SMILES (canonical and isomeric)
CC1=NN(C(=C1C(=O)C2=C(C=C(C=C2)Cl)Cl)OCC(=O)C3=CC=CC=C3)C

Synonyms

  • Paicer
  • pyrazoxyfene
  • 2-(4-(2,4-Dichlorobenzoyl)-1,3-dimethylpyrazol-5-yloxy)acetophenone
  • SL 49
  • 2-((4-(2,4-Dichlorobenzoyl)-1,3-dimethyl-1H-pyrazol-5-yl)oxy)-1-phenylethanone
  • Ethanone, 2-((4-(2,4-dichlorobenzoyl)-1,3-dimethyl-1H-pyrazol-5-yl)oxy)-1-phenyl-
  • 2-[4-(2,4-Dichlorobenzoyl)-1,3-dimethylpyrazol-5-yloxy]acetophenone
  • 2-{[4-(2,4-dichlorobenzoyl)-1,3-dimethyl-1H-pyrazol-5-yl]oxy}-1-phenylethan-1-one
  • 2-((4-(2,4-dichlorobenzoyl)-1,3-dimethyl-1H-pyrazol-5-yl)oxy)-1-phenylethan-1-one
  • 2-{[4-(2,4-dichlorobenzoyl)-1,3-dimethyl-1H-pyrazol-5-yl]oxy}-1-phenylethanone
  • 2-[[4-(2,4-dichlorobenzoyl)-1,3-dimethyl-1h-pyrazol-5-yl]oxy]-1-phenylethanone
  • Ethanone, 2-[[4-(2,4-dichlorobenzoyl)-1,3-dimethyl-1H-pyrazol-5-yl]oxy]-1-phenyl-
  • 2-[4-(2,4-dichlorobenzoyl)-2,5-dimethylpyrazol-3-yl]oxy-1-phenylethanone
  • 1,3-dimethyl-4-(2,4-dichlorobenzoyl)-5-phenacyloxypyrazole
  • 2-[4-(2,4-dichlorobenzoyl)-2,5-dimethyl-pyrazol-3-yl]oxy-1-phenyl-ethanone
  • Pyrazoxyfen, PESTANAL(R), analytical standard

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
403.27 g/molcalc.
Exact mass
402.0538 Dacalc.
LogP (octanol/water)
4.53calc.
Topological polar surface area
61.19 Ųcalc.
Hydrogen bond donors
0calc.
Hydrogen bond acceptors
4calc.
Rotatable bonds
6calc.
Heavy atoms
27calc.
Rings
3calc.
Aromatic rings
3calc.
Fraction sp3 carbons
0.15calc.
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=C(COc1[nH]ncc1C(=O)c1ccccc1)c1ccccc1

O=C(COc1[nH]ncc1C(=O)c1ccccc1)c1ccccc1

3 rings, 23 atoms.

1 other chemical 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
GHS09: Hazardous to the environment
Hazardous to the environment

Hazard statements

  • H302Harmful if swallowed.
  • H400Very toxic to aquatic life.
Precautionary statements (7)
  • P264Wash skin thoroughly after handling.
  • P270Do not eat, drink or smoke when using this product.
  • P273Avoid release to the environment.
  • P301 + P317If swallowed: Get medical help.
  • P330Rinse mouth.
  • P391Collect spillage.
  • 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

Pyrazoxyfen suppliers

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Pyrazoxyfen price

Indicative price range per kg from live supplier offers

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Suppliers quote this chemical on request. Send one free request and compare quotes side by side.

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Uses and applications

What the substance is used for, by industry and function

Roles

  • agrochemical
  • carotenoid biosynthesis inhibitor
  • enzyme inhibitor
  • herbicide
  • pathway inhibitor
  • pesticide
  • pro-agent
  • proherbicide
  • propesticide

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 Pyrazoxyfen 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 Pyrazoxyfen is indicative (it was assigned by structure rules). Confirm the classification with your customs broker before shipping.

Frequently asked questions

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

What is Pyrazoxyfen?

Pyrazoxyfen is a member of the class of pyrazoles that is 1,3-dimethylpyrazole which is substituted at positions 4 and 5 by 2,4-dichlorobenzoyl and 2-oxo-2-phenylethoxy groups, respectively.

What is the CAS number of Pyrazoxyfen?

The CAS registry number of Pyrazoxyfen is 71561-11-0.

What is the molecular formula and weight of Pyrazoxyfen?

The molecular formula of Pyrazoxyfen is C20H16Cl2N2O3 and its molar mass is 403.27 g/mol.

What is Pyrazoxyfen used for?

Known uses and roles of Pyrazoxyfen include herbicides in agriculture and crop protection, agrochemical, carotenoid biosynthesis inhibitor, enzyme inhibitor, herbicide and 5 more.

Is Pyrazoxyfen hazardous?

Pyrazoxyfen carries the GHS signal word "Warning". Main hazards: harmful if swallowed, very toxic to aquatic life. This summary is not an SDS, always read the supplier safety data sheet.

What is the HS code of Pyrazoxyfen?

Pyrazoxyfen 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 Pyrazoxyfen?

Post a free request on CompoundList and suppliers of Pyrazoxyfen will send you quotes. Your contact details stay private until you accept a quote.

What is the price of Pyrazoxyfen?

Suppliers quote Pyrazoxyfen 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 Pyrazoxyfen

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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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