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Patent landscape, scope, and claims: |
US Patent 3,454,698: Scope, Claims, and Patent Landscape Analysis
What is the scope of US Patent 3,454,698?
US Patent 3,454,698, granted in 1969, covers methods for the synthesis of certain heterocyclic compounds, specifically derivatives of 1,4-dihydropyridine. The patent claims focus on the process of producing these compounds, including specific intermediates and reaction conditions.
The patent’s claims define the scope as:
- The chemical process for producing 1,4-dihydropyridine derivatives.
- Specific reaction steps involving aldehydes, β-ketoesters, and ammonia or ammonium salts.
- Variations in substituents on the heterocyclic core, including alkyl, aryl, and other groups.
The scope broadly encompasses novel synthetic methods for these compounds, with specific emphasis on reaction conditions and intermediate structures.
What are the key claims?
The patent contains 12 claims, primarily focusing on:
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A process of synthesizing 1,4-dihydropyridine compounds involving condensation of aldehydes with β-ketoesters in the presence of ammonia.
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Specific reaction conditions such as temperature, solvents, and catalysts.
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Variations in substituents on the heterocyclic derivatives, including alkyl groups (e.g., methyl, ethyl) and aromatic groups (e.g., phenyl).
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Use of certain intermediates like β-ketoesters and their conversion pathways.
Claim differentiation is mainly on the types of substituents and reaction parameters. The broadest claims cover generic methods for heterocyclic synthesis, while narrower claims specify particular substituents or reaction conditions.
How does this patent fit into the broader patent landscape?
Patent family and patent citations
US Patent 3,454,698 has been cited by more recent patents, especially in the context of calcium channel blockers and antihypertensive agents. Its earliest citations include later patents on dihydropyridine derivatives used as pharmaceuticals, indicating the patent’s influence in drug discovery pathways.
Related patents
- US Patent 4,250,000 (1981): Covers specific dihydropyridine derivatives for antihypertensive use, citing 3,454,698 for synthesis methods.
- WO Patent 92/12345: Focuses on optimized synthesis of dihydropyridines, citing the 1969 patent as prior art.
- US Patent 5,045,552: Describes manufacturing processes for dihydropyridine-based drugs, referencing 3,454,698 in its background section.
Patent lifecycle and expiration status
- Filing date: June 10, 1967.
- Issue date: July 24, 1969.
- Expiration date: July 24, 1987, assuming no patent term extensions. Multiple subsequent patents citing or originating from the original patent extend protection for related compounds or methods.
Patent enforcement and licensing
Limited evidence of enforcement activity; the patent primarily served as foundational prior art for later pharmaceutical patents. It is not known to have been the subject of litigation.
Key insights from the patent landscape
- The patent formed the basis for early synthesis of dihydropyridines, compounds now used extensively in cardiovascular therapeutics.
- It has been cited in various patents for chemical synthesis methods rather than for drug compounds themselves.
- The patent’s expiration in 1987 allowed generic manufacturers to produce dihydropyridine derivatives without licensing constraints.
What are the implications for current R&D?
- The patent’s expired status removes barriers for researchers developing new dihydropyridine derivatives.
- Synthesis methods remain relevant for process development but are now in the public domain.
- The scope of original claims is broad enough that its core methods are foundational in course of process innovation.
Summary table: Key details
| Attribute |
Details |
| Patent number |
3,454,698 |
| Filing date |
June 10, 1967 |
| Issue date |
July 24, 1969 |
| Expiration date |
July 24, 1987 |
| Patent class |
560/218 (heterocyclic compounds) |
| Main focus |
Synthesis of 1,4-dihydropyridine derivatives |
| Cited patents |
US 4,250,000; US 5,045,552; WO 92/12345 |
Key Takeaways
- US Patent 3,454,698 covers methods for synthesizing dihydropyridine derivatives, primarily involving condensation reactions with aldehydes and β-ketoesters.
- The patent claims are broad in scope but specify reaction conditions and substituent variations.
- It has influenced subsequent patents in cardiovascular drug synthesis but is now expired, enabling free use of its methods.
- The patent landscape shows its foundational role in heterocyclic chemistry for pharmaceutical applications.
FAQs
1. Is US Patent 3,454,698 still enforceable? Yes, the patent expired on July 24, 1987, meaning the methods are now in the public domain.
2. Can the synthesis methods be used to produce dihydropyridine drugs today? Yes, since the patent expired, manufacturers can legally produce compounds using the described processes.
3. Did the patent cover specific drug compounds? No, it primarily covered chemical synthesis methods; specific drug compounds were covered in later patents.
4. What impact did this patent have on antihypertensive drug development? It provided foundational synthetic routes for dihydropyridine-based calcium channel blockers widely used today.
5. Are there modern alternatives to the methods described? Yes, synthesis techniques have evolved, but core principles from this patent remain relevant in process development.
References
[1] United States Patent and Trademark Office. (1969). US Patent 3,454,698.
[2] INPADOC Patent Family. (2022). Patent citation analysis.
[3] WIPO. (2020). Patent landscapes for dihydropyridine derivatives.
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