Details for Patent: 4,024,163

Summary for Patent: 4,024,163

Title:	Insecticides
Abstract:	New insecticides are of formula: wherein R1 represents hydrogen or a methyl group; R2 represents hydrogen or a halogeno or lower alkyl group; R3 represents hydrogen or a halogeno, lower alkyl (which is different to R2 when R2 represents a lower alkyl group) or carbo(loweralkoxy) group which contains at least 2 carbon atoms in the lower alkoxy residue when R2 represents methyl or R2 and R3 together with the carbon atom to which they are attached represent a cycloalkylene ring having at least one endocyclic carbon to carbon double bond; with the proviso that (a) R2 and R3 each represent hydrogen only when R1 represents methyl and (b) R3 contains at least 2 carbon atoms when R1 and R2 each represent hydrogen; and R represents a group which form insecticidal esters with chrysanthemic acid e.g. 5-benzyl-3-furylmethyl, 3-phenoxybenzyl, alpha -cyano-3-phenoxybenzyl. The esters are prepared by forming the ester linkage conventionally or by a Wittig reaction using a 3-formyl- or 3-acetyl-2,2-dimethyl cyclopropane carboxylic acid esterified with the desired residue or by an alkyl group which is subsequently converted to the desired residue.
Inventor(s):	Michael Elliott, Norman Frank Janes, David Allen Pulman
Assignee:	BTG International Ltd
Application Number:	US05/497,056
Patent Claim Types: see list of patent claims	Use; Composition;

United States Patent 4,024,163: Claim Scope, Expiration, and Pyrethroid Patent Landscape

United States Patent 4,024,163 is an early foundational patent covering synthetic pyrethroid insecticides, including compounds corresponding to permethrin-type, cypermethrin-type, and related halogenated cyclopropane carboxylate esters. The patent issued May 17, 1977, and its pre-URAA term expired 17 years after issuance, on May 17, 1994. It has no current exclusionary force in the United States. Its commercial importance is historical: later patents, regulatory registrations, formulation patents, manufacturing patents, and stereoisomer-specific rights became more relevant to the market.

The claims divide into four structural families:

1. 5-Benzyl-3-furylmethyl esters.
2. 3-Phenoxybenzyl esters.
3. Alpha-cyano-3-phenoxybenzyl esters.
4. Alpha-cyano-5-benzyl-3-furylmethyl esters.

The acid portion is based on 2,2-dimethyl-3-halovinylcyclopropane carboxylic acids, including dichlorovinyl, dibromovinyl, and difluorovinyl variants. The patent also claims compositions and methods of insect control.

What does United States Patent 4,024,163 cover?

Patent 4,024,163 covers insecticidal esters formed by combining a substituted cyclopropane carboxylic acid with selected alcohol moieties. The central acid scaffold is:

• 2,2-dimethylcyclopropane carboxylic acid;
• a 3-halovinyl substituent on the cyclopropane ring;
• cis, trans, racemic, and selected optically active configurations.

The principal alcohol substituents are:

Claim family	Alcohol residue	Representative commercial class
Claims 1-7	5-benzyl-3-furylmethyl	Furylmethyl pyrethroid analogs
Claims 8-17	3-phenoxybenzyl	Permethrin-type compounds
Claims 18-29	Alpha-cyano-3-phenoxybenzyl	Cypermethrin-type compounds
Claims 30-34	Alpha-cyano-5-benzyl-3-furylmethyl	Alpha-cyano furylmethyl analogs

The independent claims are composition-of-matter claims. Claims 6, 16, 28, and 33 extend the coverage to insecticidal compositions. Claims 7, 17, 29, and 34 cover methods of insect control.

How are the 34 claims organized?

The claims use a repeated structure. Each independent compound claim establishes a broad genus, while dependent claims identify halogen combinations, stereochemical forms, specific compounds, and use categories.

Claims	Scope	Claim type
1	5-Benzyl-3-furylmethyl ester with independently selected halogens	Independent compound
2-5	Dichlorovinyl, difluorovinyl, halogen selection, and stereochemistry	Dependent compounds
6	Composition with diluent or carrier	Composition
7	Applying compound to insect or susceptible environment	Method
8	3-Phenoxybenzyl ester genus	Independent compound
9-15	Dichlorovinyl, difluorovinyl, bromine/chlorine, and stereochemical forms	Dependent compounds
16	Composition with diluent or carrier	Composition
17	Insect-control method	Method
18	Alpha-cyano-3-phenoxybenzyl ester genus	Independent compound
19-27	Dibromovinyl, difluorovinyl, dichlorovinyl, and stereochemical forms	Dependent compounds
28	Composition with diluent or carrier	Composition
29	Insect-control method	Method
30	Alpha-cyano-5-benzyl-3-furylmethyl ester genus	Independent compound
31-32	Halogen and stereochemical limitations	Dependent compounds
33	Composition with diluent or carrier	Composition
34	Insect-control method	Method

The claim structure attempts to capture both the active molecule and downstream use of the molecule in an insecticidal formulation.

What chemical structures fall within the patent claims?

2,2-Dimethyl-3-halovinylcyclopropane acid core

The acid portion has a cyclopropane ring with:

• geminal methyl groups at the 2-position;
• a halovinyl substituent at the 3-position;
• a carboxylate ester linkage;
• cis, trans, racemic, and selected 1R configurations.

The halovinyl group can include:

• 2,2-dichlorovinyl;
• 2,2-dibromovinyl;
• 2,2-difluorovinyl;
• other combinations falling under the term “halogen,” subject to the relevant claim language.

Because claims 1, 8, 18, and 30 state that R2 and R3 independently represent halogen, the independent claims are broader than the dependent claims limited to bromine, chlorine, or fluorine. The dependent claims narrow the genus but do not define the full scope of the independent claims.

Alcohol residues

The alcohol portion is commercially important.

The 3-phenoxybenzyl group in claims 8-17 is the alcohol residue associated with permethrin-type chemistry. The alpha-cyano-3-phenoxybenzyl group in claims 18-29 is associated with cypermethrin-type chemistry and related alpha-cyano pyrethroids.

The 5-benzyl-3-furylmethyl and alpha-cyano-5-benzyl-3-furylmethyl residues cover related furylmethyl pyrethroids. These claims are structurally distinct from the 3-phenoxybenzyl series and should be analyzed separately in a freedom-to-operate review.

Which commercial insecticides are most closely associated with the patent?

Permethrin-type compounds

Claims 8-17 are the most relevant to permethrin-type chemistry. A representative structure is 3-phenoxybenzyl cis-trans 2,2-dimethyl-3-(2,2-dichlorovinyl)cyclopropane carboxylate.

Permethrin is generally described as a mixture of cis and trans stereoisomers. The patent expressly claims cis, trans, cis-trans, racemic, and selected optically active forms. That claim architecture was commercially significant because pesticide products frequently use stereoisomeric mixtures rather than a single enantiomer.

Cypermethrin-type compounds

Claims 18-29 are directed to alpha-cyano-3-phenoxybenzyl esters. A representative cypermethrin structure contains:

• an alpha-cyano-3-phenoxybenzyl alcohol residue;
• a 2,2-dimethylcyclopropane carboxylate acid;
• a 2,2-dichlorovinyl substituent;
• multiple stereochemical forms.

Claims 25-27 specifically identify racemic cis-trans, racemic cis, and a [1R,cis] dichlorovinyl species. Claim 20 also identifies an isomer by positive optical rotation in ethanol, a technique used in older patents to distinguish enantiomeric material.

Deltamethrin and related stereochemical products

The patent’s alpha-cyano-3-phenoxybenzyl framework is chemically related to the broader family of alpha-cyano pyrethroids. Deltamethrin, however, has a distinct stereochemical and substituent profile and became associated with separate patenting and regulatory work. A compound may be chemically related to a claimed genus without being commercially protected by this patent today. The relevant question is whether a later patent, registration, formulation, or manufacturing process remains active.

What is the patent status and expiration date?

Event	Date or status
U.S. patent	4,024,163
Title	Insecticidal esters
Issue date	May 17, 1977
Patent term regime	Pre-URAA, generally 17 years from grant
Expiration	May 17, 1994
Current status	Expired
Current blocking effect	None in the United States

Patent 4,024,163 was granted before the 1995 change to the United States patent term system. Its term was therefore measured primarily from the grant date rather than 20 years from the earliest effective filing date. The patent is now well outside its enforceable term. [1]

No Paragraph IV challenge is relevant to this patent today. Paragraph IV certifications apply to abbreviated new drug applications under the Hatch-Waxman framework. The compounds covered by Patent 4,024,163 are pesticides, not FDA-approved small-molecule drugs for purposes of the Orange Book generic-drug pathway.

What is the Orange Book status of Patent 4,024,163?

Patent 4,024,163 has no Orange Book listing.

The patent claims insecticidal compounds, pesticide compositions, and insect-control methods. Pesticide products are principally regulated by the Environmental Protection Agency under the Federal Insecticide, Fungicide, and Rodenticide Act. The FDA may regulate certain products containing insecticides when they are drugs, cosmetics, medical devices, or animal-health products, but that does not place the underlying pesticide patent in the Orange Book. [2, 3]

The distinction matters:

Issue	Status
Orange Book listing	None
Paragraph IV litigation	Not applicable to this patent
EPA pesticide registration	Relevant
FDA drug approval	Product-specific and separate
Patent enforceability	Expired

Did the patent protect formulations or only active ingredients?

The patent contains composition claims, but those claims are relatively broad and conventional. Claims 6, 16, 28, and 33 require:

• a claimed active compound; and
• a diluent or carrier.

They do not recite a detailed delivery system, concentration range, particle-size distribution, solvent system, encapsulation structure, synergist, propellant, or release profile.

The formulation claims could therefore cover basic insecticidal compositions containing a claimed active compound. They would not necessarily anticipate later patents directed to:

• microencapsulated pyrethroids;
• polymeric controlled-release systems;
• specific emulsifiable concentrates;
• water-dispersible granules;
• aerosol delivery systems;
• treated textile or polymer substrates;
• synergist combinations such as piperonyl butoxide;
• veterinary spot-on formulations;
• agricultural tank mixtures.

Those later rights must be assessed independently. Expiration of the active-ingredient patent does not eliminate later formulation patents.

What method-of-use rights does the patent contain?

Claims 7, 17, 29, and 34 cover methods of insect control by applying a claimed compound to:

1. an insect; or
2. an environment susceptible to insect attack.

The method language is broad and does not limit the claim to a specific insect species, crop, application rate, geographic location, or delivery method. The claim can encompass direct insect treatment and environmental treatment, subject to ordinary claim-construction principles.

These method claims expired with the patent. They do not create current barriers to use of the covered active ingredients. Later method patents may still cover narrower applications such as:

• mosquito control;
• vector-borne disease prevention;
• termite control;
• crop-specific pest treatment;
• indoor residual spraying;
• textile impregnation;
• animal ectoparasite treatment.

How strong was the patent estate?

The patent was strong historically as a foundational composition patent because it combined several commercially valuable features:

• broad halogen selection;
• multiple alcohol residues;
• explicit stereochemical coverage;
• composition claims;
• insect-control method claims;
• claims to racemic and optically active materials.

Its present strength is zero as an enforceable U.S. patent. The commercial relevance is prior-art and lineage value rather than exclusionary value.

Estate characteristic	Assessment
Core composition claims	Historically broad
Stereochemical coverage	Broad, with specific optically active claims
Formulation coverage	Basic carrier compositions only
Method coverage	Broad but expired
Manufacturing coverage	Not the principal focus of the supplied claims
Current enforcement value	None
Prior-art significance	High for later pyrethroid examination
Freedom-to-operate significance	Relevant as expired prior art, not as a blocking right

The lack of detailed manufacturing claims also means that process freedom-to-operate cannot be determined solely from Patent 4,024,163. Later patents may cover stereoselective synthesis, halovinyl intermediates, purification, crystallization, or enriched isomer production.

What patent landscape surrounds permethrin and cypermethrin?

The broader landscape has four layers.

Foundational active-ingredient patents

These include early patents such as Patent 4,024,163 and related international filings directed to synthetic pyrethroid structures. They established the principal chemical classes and stereochemical concepts.

Stereoisomer and enriched-mixture patents

Later patents often focused on:

• a single active enantiomer;
• a defined cis-to-trans ratio;
• a defined enantiomeric ratio;
• improved insecticidal activity;
• reduced mammalian toxicity;
• improved photostability;
• a specific isomer composition.

A generic producer or pesticide registrant must distinguish the expired genus from later claims directed to narrower stereochemical compositions.

Formulation and delivery patents

Later rights commonly cover:

• suspension concentrates;
• emulsifiable concentrates;
• wettable powders;
• water-dispersible granules;
• controlled-release capsules;
• aerosols;
• treated fibers and fabrics;
• veterinary topical dosage forms;
• household insect-control devices.

These patents are more likely to affect current launch risk than Patent 4,024,163.

Manufacturing and regulatory data rights

Commercial barriers may also arise from:

• process patents;
• intermediate patents;
• proprietary crystallization methods;
• confidential manufacturing know-how;
• EPA registration data;
• data-compensation periods;
• formulation-specific registrations;
• contractual licensing restrictions.

A patent expiration does not transfer EPA registrations, trade secrets, or proprietary analytical methods to a new entrant.

Which companies historically controlled the relevant technology?

The synthetic pyrethroid field involved the U.K. National Research Development Corporation, the Rothamsted research community, Shell, Roussel Uclaf, Sumitomo Chemical, Bayer, American Cyanamid, FMC, and later multinational crop-protection companies. Commercial rights frequently changed through assignments, licenses, acquisitions, and product-line transfers.

Patent ownership should be distinguished from product registration ownership. A company may own a later formulation patent without owning the foundational compound patent. It may also hold an EPA registration without holding any enforceable patent on the active ingredient.

An ownership and licensing review should therefore examine:

• assignment records at the USPTO;
• continuation and divisional filings;
• foreign counterparts;
• license agreements;
• product-specific registrations;
• later patents assigned to successor companies.

Are there current generic-entry risks from Patent 4,024,163?

There is no current U.S. patent-entry risk from Patent 4,024,163 itself. A manufacturer can no longer be sued for infringement of this patent based on making, using, selling, or importing a covered compound in the United States.

Current risks may arise from other sources:

Risk category	Potential relevance
Later compound patents	Narrow stereoisomers or new analogs
Formulation patents	Delivery systems and dosage forms
Process patents	Stereoselective or improved manufacturing
EPA registration	Regulatory approval and data requirements
Trade secrets	Manufacturing conditions and purification
Trademarks	Brand and product-name restrictions
Contract rights	Licenses, supply agreements, and territories
Foreign patents	Different expiry dates and claim scope

For a conventional permethrin or cypermethrin active ingredient, the principal current barriers are usually regulatory, manufacturing, quality-control, and commercial rather than infringement of the 1977 patent.

What litigation and settlement issues remain relevant?

Patent 4,024,163 cannot support a new U.S. infringement action because it expired in 1994. Any historical infringement dispute under the patent would be subject to expiration, applicable limitation periods, prior settlements, and the specific procedural posture of the case.

Settlement agreements may still matter commercially if they contain:

• continuing supply restrictions;
• territorial limitations;
• confidentiality provisions;
• royalty obligations tied to later patents;
• covenants not to sue under other patents;
• regulatory-data access restrictions.

Those contractual terms do not revive the expired patent. They may, however, affect market access independently of patent enforceability.

What geographic coverage did the patent have?

The supplied claims are U.S. claims. They have no direct legal effect in Europe, Japan, China, India, Brazil, or other jurisdictions.

Foreign counterparts may have had:

• different claim scope;
• different prosecution outcomes;
• different expiration dates;
• national-phase or convention filing differences;
• supplementary protection or term-adjustment rules;
• separate assignment histories.

A global launch review must map each jurisdiction independently. The U.S. expiration date cannot be used as a proxy for foreign freedom to operate.

Key Takeaways

• U.S. Patent 4,024,163 covers broad synthetic pyrethroid ester families based on halogenated 2,2-dimethylcyclopropane carboxylic acids.
• The principal claim groups cover 5-benzyl-3-furylmethyl, 3-phenoxybenzyl, alpha-cyano-3-phenoxybenzyl, and alpha-cyano-5-benzyl-3-furylmethyl esters.
• The patent includes compound, insecticidal composition, and insect-control method claims.
• Claims expressly address cis, trans, racemic, mixed, and selected optically active stereoisomers.
• The patent issued May 17, 1977, and expired May 17, 1994.
• It has no current U.S. blocking effect and is not an Orange Book patent.
• Paragraph IV analysis is not applicable because the patent covers pesticides rather than an Orange Book-listed drug.
• Later formulation, manufacturing, stereoisomer, regulatory, and foreign patents may still affect commercial entry.
• Current market risk should focus on active follow-on patents and EPA registration requirements, not Patent 4,024,163.

FAQs

Is Patent 4,024,163 still enforceable against permethrin manufacturers?

No. The patent expired on May 17, 1994, and cannot support a current U.S. patent infringement claim.

Does Patent 4,024,163 cover cypermethrin?

Its claims cover alpha-cyano-3-phenoxybenzyl ester structures that are associated with cypermethrin-type chemistry. Exact coverage depends on the claimed halovinyl substituent and stereochemical form.

Does patent expiration eliminate EPA registration requirements?

No. Patent expiration does not eliminate EPA registration, labeling, manufacturing, residue, safety, or data requirements for pesticide products.

Can a later formulation patent block sale of an old pyrethroid active ingredient?

Yes. A later patent may cover a particular formulation, delivery system, mixture, dosage form, or application even when the active ingredient patent has expired.

Are foreign versions of Patent 4,024,163 also expired?

Not necessarily on the same date. Each foreign patent must be reviewed under its national filing, grant, term, and maintenance rules.

References

1. United States Patent and Trademark Office. (1977). Insecticidal esters (U.S. Patent No. 4,024,163).

2. U.S. Environmental Protection Agency. (2023). Pesticide registration manual. https://www.epa.gov/pesticide-registration

3. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. https://www.fda.gov/drugs/drug-approvals-and-databases/approved-drug-products-therapeutic-equivalence-evaluations-orange-book

4. World Intellectual Property Organization. (n.d.). PATENTSCOPE patent search. https://patentscope.wipo.int

5. United States Patent and Trademark Office. (n.d.). Patent Center. https://patentcenter.uspto.gov

Drugs Protected by US Patent 4,024,163

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate

Foreign Priority and PCT Information for Patent: 4,024,163

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
	24809/72	May 25, 1972
	24810/72	May 25, 1972
	30838/72	Jun 30, 1972
	59184/72	Dec 21, 1972

International Family Members for US Patent 4,024,163

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	223447
Australia	5610573
Australia	7224974
Belgium	800006