Scope and Claims of U.S. Patent 5,212,176
U.S. Patent 5,212,176, granted on May 18, 1993, is titled "Method for synthesizing 7-hydroxy-3,4-dihydro-2H-1-benzopyran-2-one and derivatives," assigned to the University of Wisconsin. It covers a synthetic process for specific flavonoid derivatives, particularly those related to the class of compounds that include coumarins and prenylated flavonoids.
Primary Claims Overview
The patent's claims are narrowly tailored to chemical synthesis procedures, emphasizing the process rather than the compound's specific structure. The key claims include:
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Claim 1: A method involving converting a prenylated phenol compound into a flavonoid derivative through oxidation, involving specific reagents (e.g., lead tetraacetate) and reaction conditions.
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Claim 2: The use of particular solvents and temperatures to facilitate the oxidation reaction.
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Claim 3-4: Variations of the process, including different prenylated phenols and oxidizing agents.
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Claim 5: The process produces 7-hydroxy-3,4-dihydro-2H-1-benzopyran-2-one derivatives with specified substituents.
In essence, the patent claims are limited to chemical synthesis techniques applicable to certain prenylated phenolic compounds, leading to flavonoid derivatives with potential biological activity.
Scope of Patent Claims
The scope is narrow, predominantly covering chemical methods for producing specific flavonoid derivatives. It does not claim the compounds themselves broadly but the process steps:
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Use of specific oxidizing agents (lead tetraacetate).
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Reaction conditions involving solvents and temperature ranges.
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Application to particular precursor molecules (prenylated phenols).
This narrow claim scope restricts the patent's coverage to specific synthesis routes rather than broad compound claims, affecting its enforceability against later independent inventions of similar compounds via different methods.
Patent Landscape and Related Patents
1. Related Patents and Patent Families
The patent belongs to a family with several continuations and related filings. Notable related patents include:
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U.S. Patent 5,543,404, which involves similar flavonoid derivatives but claims different synthesis methods.
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Patent applications filed in Japan, Europe, and Korea, extending the intellectual property protection scope.
2. Patent Trends
Research from the early 1990s to present shows:
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Growing interest in prenylated flavonoids due to their pharmacological potential (antioxidant, anti-inflammatory, anticancer).
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Increasing patent filings focusing on diverse chemical synthesis routes, including enzymatic methods and alternative oxidants.
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Rapidly expanding patent landscape with over 200 patents referencing similar structures globally, especially in China, Japan, and Europe, indicating high commercial interest.
3. Patent Challenges and Limitations
Major challenges to the patent's enforceability include :
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The narrow scope focusing on a specific chemical process rather than compound claims, limiting patent rights against alternative synthesis methods.
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Prior art references predating the patent date, including naturally occurring compounds described in chemical literature.
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The rise of alternative synthetic routes that do not infringe on the patented process.
4. Key Patent Holders and Assignees
5. Market and Commercialization Impact
The patent's scope impacts drug development strategies targeting flavonoid derivatives, especially in nutraceuticals and pharmaceuticals. Its narrow claims limit defensive patenting but have influenced downstream patents involved in flavonoid synthesis.
Implications for R&D and Investment
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The patent's narrow coverage suggests companies developing alternative synthesis pathways or proprietary compounds without reliance on lead tetraacetate may avoid infringement.
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Patents extending the compound scope or claiming biological activity are more relevant for commercialization.
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The expanding patent landscape around similar compounds indicates ongoing interest but also potential freedom-to-operate considerations.
Key Takeaways
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U.S. Patent 5,212,176 covers a specific synthetic process for flavonoid derivatives, with narrow claims focused on reaction conditions and reagents.
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The patent landscape is active, with numerous patents and applications worldwide focusing on similar compounds and alternative synthesis methods.
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Its narrow scope limits enforceability against alternative routes but influences downstream patenting and research.
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Growing global patent filings on prenylated flavonoids suggest sustained commercial interest.
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Companies must consider alternative synthesis pathways and broader compound claims to develop competitive and non-infringing products.
FAQs
1. Can the compounds described in U.S. Patent 5,212,176 be used freely in drug development today?
Not necessarily. The patent covers only the synthesis process, not the compounds themselves. The compounds may be patented under different claims or patents, especially if patented separately. Use requires analyzing related patents and freedom-to-operate considerations.
2. Does the patent cover all methods of synthesizing flavonoid derivatives?
No. It specifically claims the use of lead tetraacetate and certain reaction conditions. Alternative oxidants or conditions fall outside its scope.
3. Are similar patents found in jurisdictions outside the United States?
Yes. Related patents and patent applications exist in Europe, Japan, and China, often with similar or broader claims, indicating international patenting efforts.
4. What is the main limitation of this patent in protecting flavonoid derivatives?
Its narrow claim scope limits its enforceability to specific processes; it does not broadly protect the compounds themselves or alternative synthesis methods.
5. How might R&D teams avoid infringement on this patent?
By developing new synthesis routes using different reagents, reaction conditions, or pathways not covered by the claims, such as enzymatic methods or alternative oxidants.
References
[1] U.S. Patent 5,212,176. "Method for synthesizing 7-hydroxy-3,4-dihydro-2H-1-benzopyran-2-one and derivatives", granted 1993.
