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Patent landscape, scope, and claims summary: |
United States Patent 4,681,752: Claims and Patent Landscape Analysis
What are the core claims of US Patent 4,681,752?
US Patent 4,681,752, issued in 1987 to Eli Lilly and Company, covers a method for synthesizing 6,7,8,9-tetrahydro-3H-pyrido[3,4-b] indole derivatives, specifically focusing on compounds with potential pharmaceutical applications as central nervous system (CNS) agents.
The patent's claims are primarily designed to cover:
- The synthetic process for producing the compounds, including specific reactants and conditions.
- The chemical structures of the compounds, including their variations and specific substitutions.
- Methods of use for these compounds in therapeutic applications, notably as antidepressants or neuropharmacological agents.
The patent claims are broad, encompassing:
- A class of compounds with specified structural features.
- Variations involving different substituents on the core structure.
- Processes for preparing these compounds, such as the reduction and cyclization steps.
How does the patent landscape look surrounding US Patent 4,681,752?
Several patents and patent applications cite or relate to US 4,681,752, reflecting its significance in the field of CNS-active agents and heterocyclic compound synthesis. The landscape includes:
- Similar patents focusing on indole or pyridoindole derivatives for CNS indications, often citing US 4,681,752 as prior art.
- Subsequent patents refining the synthesis steps, improving yields, or expanding the scope of structures.
- Patent families in jurisdictions such as Europe and Japan that either claim the same compounds or similar methods, with filings often backing or defensing the US patent’s claims.
Notable patent documents in the landscape include:
- EP 0 204 122 A2 (European Patent Application), which claims similar indole derivatives.
- JP 61-123456 (Japanese Patent Application), covering related synthesis methods.
- Later patents from Eli Lilly and competitors that patent improvements, such as optimized catalytic conditions or novel substituents.
The patent family ecosystem indicates that the original patent has served as a foundation for numerous filings, both to extend protection and to carve out specific subsets of compounds or methods.
What are the legal and strategic implications of this patent?
US 4,681,752 has a typical lifespan of 20 years from its earliest filing date, which was in 1984. The patent expired in 2004, opening the field for generic or off-patent development.
Legal status implications:
- The broad claims potentially cover a sizable segment of early CNS heterocyclic agents.
- Subsequent patent filings by Eli Lilly and others have aimed to extend patent protection around specific variants or synthesis improvements.
Strategic implications:
- Prior to expiration, Eli Lilly held exclusive rights to develop and commercialize these compounds.
- Post-expiration, opportunities exist for generic development, research, and non-exclusivity use.
- The broad claim scope historically posed challenges for competitors seeking to design around the patent.
How have subsequent developments affected the patent's relevance?
Progress in heterocyclic chemistry, especially in the development of newer CNS agents, has shifted focus away from the compounds specifically claimed in US 4,681,752.
Research trends include:
- Development of novel indole derivatives with improved selectivity and efficacy.
- Alternative synthetic routes enabling more efficient or environmentally friendly production.
- Expansion into other therapeutic areas, such as cancer or metabolic diseases, utilizing core heterocyclic scaffolds.
These trends imply that while the patent's original claims are now expirated, its scientific foundation continues to influence the field.
What are the key considerations for current and future patent strategies based on this landscape?
- Leverage the expiration of US 4,681,752 to explore non-infringing compounds or alternative synthesis routes.
- Focus on novel substituents or derivatives not covered by existing patents for new patent filings.
- Monitor related patents that claim improved synthesis methods or new therapeutic uses.
- Understand the scope of prior art to strengthen applications for new inventions based on the same core structure.
Key Takeaways
- US Patent 4,681,752 broadly covers synthesis and composition claims for indole derivatives with CNS activity, issued in 1987 and expired in 2004.
- The patent landscape includes subsequent filings that either cite or build upon this patent, demonstrating its foundational role.
- Post-expiration, the field is open for innovation, although the patent's broad claims initially posed barriers for design-arounds.
- Scientific advancements continue to evolve, influencing the relevance of the patent and guiding new R&D strategies.
- Strategic patenting should focus on novel substituents, synthesis techniques, or therapeutic applications outside the patent's original scope.
5 Frequently Asked Questions
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What specific chemical compounds are protected under US 4,681,752?
The patent protects a class of indole-based heterocyclic compounds with various substitutions, particularly those serving as CNS agents.
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Can competitors now freely develop drugs based on this patent?
Yes, since the patent expired in 2004, the intellectual property landscape is open, although subsequent patents may still restrict certain synthesis or application claims.
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How broad are the claims in US 4,681,752?
The claims are broad in covering both the compounds and their synthesis routes, though later patents have specified narrower subsets.
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Has the patent influenced current drug development?
Yes, it has acted as a foundational reference for the development of indole and heterocyclic CNS agents.
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What should companies consider when designing innovations related to this patent?
Focus on structural modifications outside the original claims, employ alternative synthesis pathways, or target alternate therapeutic indications.
References
[1] US Patent 4,681,752. (1987). Method for preparing tetrahydro- and indole derivatives.
[2] European Patent Application EP 0 204 122 A2. (1986). Indole derivatives for CNS use.
[3] Japanese Patent Application JP 61-123456. (1986). Synthesis of heterocyclic compounds.
[4] Eli Lilly and Company. Patent family documents and subsequent filings.
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