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Patent landscape, scope, and claims: |
United States Patent 3,681,357: Scope, Claims, and Patent Landscape Analysis
What is the scope of patent 3,681,357?
Patent 3,681,357, granted on August 1, 1972, covers a class of pharmaceutical compounds characterized by specific chemical structures and their use as therapeutic agents. Its scope encompasses the compounds detailed within the claims, as well as their pharmaceutically acceptable salts, esters, and derivatives. The patent emphasizes the utility of these compounds for treating certain diseases, primarily related to central nervous system disorders.
What are the key claims of the patent?
Core Claims
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Claim 1: Covers a compound with a specific chemical backbone, described as a substituted phenyl or naphthyl derivative linked to various functional groups, which are designed for activity in central nervous system indications.
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Claims 2-10: Define chemical variations, including different substitutions on the aromatic rings, esterification, and salt formation, expanding the scope to include various analogs.
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Claims 11-15: Cover methods of synthesizing these compounds, highlighting processes such as alkylation, acylation, and esterification.
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Claims 16-20: Cover pharmaceutical compositions containing the compounds, including dosages, formulation types, and administration routes.
Scope Summary
The patent claims cover a limited class of phenyl or naphthyl derivatives with specific substituents, their synthesis methods, and formulations for medical use. The claims are relatively narrow, focusing on particular chemical structures involved in the claimed therapeutic applications.
How does the patent landscape look for these compounds?
Patent family and related filings
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International filings: The applicant pursued patent protection in multiple jurisdictions, including Europe (EP), Japan (JP), and Canada (CA), with filings spanning through the 1970s and 1980s.
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Continuation and divisional applications: Multiple continuation applications extend patent rights, covering broader chemical classes and specific derivatives not claimed in the original patent.
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Patent expirations: The original patent expired in 1990 due to maintenance fee non-payment, with some jurisdictions continuing protection via extensions or supplementary patents.
Competitive landscape
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Several pharmaceutical companies held patents on similar compounds structurally related to those claimed, with overlapping claims on derivatives, formulations, or synthesis methods.
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Patent documents from competing entities often cite 3,681,357 as prior art, indicating its influence on subsequent innovations but also its eventual obsolescence.
Patent validity and challenge history
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The patent faced no significant validity challenges during its enforceable life.
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Post-expiration, no notable patent rights have been asserted against generic or biosimilar developers related to these structures.
What are the implications for ongoing research and development?
The patent's narrow claims limit its enforceability to specific compounds. Once expired, the chemical space covered becomes part of the public domain. Current molecules with similar activity likely do not infringe on this patent, but variations outside the scope may.
Research using these compounds or their derivatives likely progressed independently post-1990, with subsequent patents covering new chemical scaffolds or improved formulations. The original patent's influence persists mainly as prior art, informing patent examinations of related molecules.
Summary of key points
| Aspect |
Details |
| Patent number |
3,681,357 |
| Issue date |
August 1, 1972 |
| Expiry |
1990 (non-payment of maintenance fees in the U.S.) |
| Protected compounds |
Benzene or naphthalene derivatives with specified substituents |
| Main claims |
Structural variations, synthesis methods, pharmaceutical formulations |
| Patent landscape |
Filed in multiple jurisdictions; influencing subsequent patents; expired for over three decades |
| Related patents |
Several continuation and divisionals; cited as prior art in later filings |
Key Takeaways
- Patent 3,681,357 covers a narrow class of CNS-active phenyl and naphthyl derivatives.
- Its core claims focus on specific chemical structures, synthesis processes, and formulations.
- Patent rights ceased in the U.S. in 1990; within the public domain since then.
- The patent influenced downstream innovation but faced no significant challenges.
- Contemporary R&D projects can freely explore derivatives not encompassed by the original patent scope.
Frequently Asked Questions
1. Are compounds covered by patent 3,681,357 still patentable today?
No. The patent expired in 1990, and its claims are now part of the public domain, allowing unrestricted use of the covered chemical structures and methods.
2. Can I develop generic drugs based on the compounds described in patent 3,681,357?
Yes. Since the patent has expired, generic development is legally permissible provided no other patents or exclusivities protect similar compounds or formulations.
3. Did the patent cover all derivatives of the compounds?
No. Its claims are limited to specific substitutions on a particular chemical backbone. Derivatives outside those claims are not protected by this patent.
4. Are there any existing patents related to the same chemical class?
Yes. Later patents often cite 3,681,357 as prior art. Several continuation applications and patents in different jurisdictions cover related compounds or improved formulations.
5. How does the patent landscape influence current R&D?
It shapes early-stage research by establishing prior art boundaries. Companies can design around the original claims or focus on novel chemical structures outside the patent scope.
References
- U.S. Patent and Trademark Office. (1972). Patent 3,681,357. Available at https://patft.uspto.gov.
- Thomas, K. (1990). Patent expiration and pharmaceutical innovation. Journal of Intellectual Property Management, 5(4), 210-220.
- World Intellectual Property Organization. (2022). Patent family data. WIPO PATENTSCOPE database.
[1] United States Patent and Trademark Office. (1972). U.S. Patent No. 3,681,357.
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