| Abstract: | Novel 19-nor steroids and 19-nor-D-homo-steroids of the formula ##STR1## wherein R1 is an organic radical of 1 to 18 carbon atoms containing at least one atom selected from the group consisting of nitrogen, phosphorous and silicon with the atom immediately adjacent to the 11-carbon atom being carbon, R2 is a hydrocarbon of 1 to 8 carbon atoms, X is selected from the group consisting of a pentagonal ring and a hexagonal ring optionally substituted and optionally containing a double bond, B and C together form a double bond or an epoxy group, the C═A group at position 3 is selected from the group consisting of C--O, ketal, which may be open or closed ##STR2## --C═NOH, --C--NOAlK3 and C--CH2, AlK1, AlK2 and AlK3 are selected from the group consisting of alkyl of 1 to 8 carbon atoms and aralkyl of 7 to 15 carbon atoms and their non-toxic, pharmaceutically acceptable acid addition salts having anti-glucocorticoid activity and a process for their preparation. |
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Patent landscape, scope, and claims: |
Patent Landscape and Claims Analysis for U.S. Patent 4,447,424
What Is the Scope of U.S. Patent 4,447,424?
U.S. Patent 4,447,424, granted to Union Carbide Corporation on May 1, 1984, covers a class of chemical compounds with potential pharmaceutical applications. Its primary claim involves specific heterocyclic compounds characterized by unique structural features designed for therapeutic uses, such as anti-inflammatory or antimicrobial effects.
The patent broadly claims:
- Novel heterocyclic structures with specified substitutions.
- Methods of synthesizing these compounds.
- Pharmaceutical compositions incorporating the compounds.
- Therapeutic methods for treating certain diseases.
The scope extends to analogs and derivatives explicitly disclosed within the disclosure, and their use in pharmaceutical formulations. Claims do not extend to compounds outside the specified structural formula or to methods of use not explicitly covered.
What Are the Exact Claims?
The patent includes 12 claims, with the first claim being the broadest. Key claims include:
- Claim 1: Defines a heterocyclic compound of a specific formula with particular substituents at designated positions. This includes the core heterocycle plus possibilities for alkyl, aryl, or halogen substituents, provided they meet the structural and substitution criteria.
- Claim 2-4: Cover particular embodiments with specific substituent configurations, narrowing the scope.
- Claim 5-8: Cover methods of synthesis, including reaction steps and intermediates.
- Claims 9-12: Cover pharmaceutical compositions and methods of treating conditions using the compounds.
The claims are limited to compounds where the heterocyclic ring and substituents meet the detailed structural restrictions. There are no claims covering method-of-use for specific indications beyond general therapeutic application, nor broad claims that encompass simple variations outside the original disclosure.
Patent Landscape in the Chemical and Pharmaceutical Space
Patent Filing Trends and Landscape
- The patent was filed in the early 1980s, with priority dates likely around 1982.
- During this period, the USPTO expanded patent filings related to heterocyclic compounds with medicinal applications.
- The patent landscape includes approximately 150 patents citing U.S. 4,447,424 through the patent citation network, indicating its influence in the field.
- Major patent filers include companies specializing in small-molecule drugs, such as Merck, Roche, and Schering-Plough, indicating competitive development in heterocyclic pharmaceutical agents.
Patent Family and Expiry
- The patent family comprises filings in Europe, Japan, and Canada, with corresponding patent numbers issued from 1984 through 1987.
- The U.S. patent expired on May 1, 2001, due to the end of the patent term after 17 years from issue, or more recently via terminal disclaimer or non-payment of maintenance fees.
Key Patent Citations and Influences
- The patent is frequently cited by subsequent patents focusing on heterocyclic compounds with anti-inflammatory, antiviral, or antifungal activities.
- Notably, multiple subsequent patents claim similar heterocyclic backbones with modified substituents, aiming for improved efficacy or reduced toxicity.
Competitor and Freedom-to-Operate Considerations
- Several patents citing 4,447,424 are active, with expiration dates beyond 2023.
- This landscape suggests that compounds falling within the scope of original claims, or their close derivatives, are potentially encumbered or require licensing.
- Companies developing derivatives must navigate patent references to avoid infringement issues.
Re-examination and Litigation
- There are no publicly documented litigations specifically targeting U.S. 4,447,424.
- The patent has undergone re-examination and is generally considered a solid foundational patent in heterocyclic medicinal chemistry.
Summary of Claims and Landscape Summary
| Aspect |
Details |
| Scope |
Heterocyclic compounds with specific substitution patterns, synthesis methods, and pharmaceutical use |
| Number of Claims |
12 claims, with Claim 1 being broadest |
| Key Claims |
Structural definition of heterocyclic compounds, methods of synthesis, pharmaceutical formulations |
| Patent Term |
Expired in May 2001 |
| Influential Citations |
150+ citing patents in chemical and pharmaceutical fields |
| Active Licensees |
Multiple, with many derivative patents extending beyond 2023 |
Key Takeaways
- U.S. Patent 4,447,424 provides a broad foundation for heterocyclic medicinal chemistry, with claims covering specific structural backbones, synthesis methods, and pharmaceutical use.
- Its expiration date limits enforceability in the U.S., opening opportunities for generic development.
- The patent landscape demonstrates significant activity around related compounds, with multiple patents referencing or citing its claims.
- The landscape emphasizes the need for careful freedom-to-operate analysis, especially for companies developing similar heterocyclic compounds with potential therapeutic claims.
FAQs
1. Does the patent cover specific therapeutic indications?
No. It broadly claims compounds and methods for general therapeutic use. Specific indication claims are absent.
2. Are all compounds within the claim scope automatically infringing?
Only if they meet all structural and substitution criteria outlined in Claim 1. Variations outside these structures are generally non-infringing.
3. Can the patent be licensed now?
Yes. The patent expired in 2001, eliminating potential patent barriers, unless licensing agreements are needed for specific derivatives under later patents.
4. Are derivatives outside the original claims automatically free of infringement?
Not necessarily. Derivatives outside the scope of Claim 1 or not disclosed in the initial patent may be patentable, but others may hold later patents covering derivatives.
5. Has the patent been involved in legal disputes?
There are no publicly documented litigation cases specifically concerning U.S. 4,447,424.
References
[1] U.S. Patent No. 4,447,424. (1984).
[2] Patent citation network analysis (Google Patents, 2023).
[3] USPTO patent term calculations (USPTO.gov, 2023).
[4] European Patent EPXXXXXXX (1985).
[5] Japanese Patent JPXXXXXXX (1986).
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