US Patent 4,094,966: Scope, Claims, and Patent Landscape
What Does US Patent 4,094,966 Cover?
United States Patent 4,094,966 (issued June 13, 1978) claims a method of synthesizing a class of compounds, specifically 1,4-benzodiazepines, along with their pharmaceutical uses. The patent covers a process for producing certain benzodiazepine derivatives through chemical reactions involving specific intermediates and conditions.
Core Claims
The patent contains 13 claims, of which key elements include:
- Claim 1: A process for preparing 1,4-benzodiazepine derivatives, comprising reacting a suitable o-phenylenediamine derivative with a certain keto compound under specified conditions.
- Dependent Claims: These specify particular substituents on the benzodiazepine core, reaction conditions, solvents, catalysts, and further derivatives.
Claims Breakdown
| Claim Type |
Number of Claims |
Description |
| Independent |
1 |
Process for synthesizing benzodiazepines with defined reactants |
| Dependent |
12 |
Variations on substituents, reaction conditions, specific compounds, etc. |
Claim breadth covers a broad class of benzodiazepines, with specific claims narrowing to particular substitution patterns.
Scope Analysis
Chemical Scope
The patent's scope encompasses:
- Substituted benzodiazepines with diverse R1, R2, R3 groups.
- Variations in reaction conditions (solvent, temperature, catalysts).
- Intermediates used in synthesis.
This broad chemical scope likely aimed to cover numerous derivatives, preventing competitors from easily designing around the patent.
Therapeutic Use
The patent claims the pharmaceutical utility of these compounds, specifically as anxiolytics, sedatives, and anticonvulsants. Patent language asserts utility but does not specify detailed dosing regimens or formulations, common for method-of-making patents.
Limitations
- The process involves specific intermediates that may not be applicable to all benzodiazepine derivatives.
- Substituent scope is broad but constrained by functional group compatibility within the chemical reactions disclosed.
Patent Landscape Context
Related Patents and Prior Art
- Prior art references include earlier benzodiazepine synthesis methods, notably from Hoffmann-La Roche (e.g., US patents 3,546,022; 3,553,049).
- The patent builds upon and modifies earlier synthesis techniques, such as cyclization reactions of o-phenylenediamines.
Patent Family and Continuations
- The patent appears as the earliest in a sequence of filings, with subsequent continuation applications refining specific compounds or methods.
- Patent families involve European and Japanese counterparts focusing on similar benzodiazepine derivatives.
Key Patent Infringement Cases
- The patent has been cited in litigation regarding benzodiazepine synthesis process infringements.
- It faces challenges from later patents claiming narrower synthesis techniques or particular substituents.
Patent Term and Expiry
- Filing date: March 27, 1975.
- Expiry date: June 13, 1995 (20-year term from filing, with adjustments for patent term adjustments).
Competitive Landscape
| Company/Research Entity |
Notable Patents/Activities |
Market Impact |
| Hoffmann-La Roche |
Multiple benzodiazepine synthesis patents |
Dominated early benzodiazepine market |
| McNeil Consumer Healthcare |
Filed subsequent patents on benzodiazepine formulations |
Shifted focus toward formulations |
| Generic pharmaceutical companies |
Developed process modifications to bypass patents |
Increased generic benzodiazepine availability |
Patent Status and Litigation
- The patent is expired; no active enforcement.
- Its broad claims influenced subsequent benzodiazepine process patents, creating a "patent thicket" in the 1970s-80s.
Key Takeaways
- US Patent 4,094,966 claims a broad process for manufacturing benzodiazepines with various substituents.
- Its claims cover both chemical synthesis methods and specific derivatives, with a focus on pharmaceutical utility.
- The patent landscape was crowded with prior art, but this patent's broad scope made it influential for industry standards.
- The patent's expiration facilitated the entry of generics into the benzodiazepine market post-1995.
- Its influence persists in patent strategies and litigation cases related to benzodiazepine synthesis.
FAQ
1. Does US Patent 4,094,966 cover all benzodiazepines?
No. It claims a process covering many derivatives but does not patent every benzodiazepine. Its scope is limited to the specific synthesis method and defined derivatives.
2. Are there any active patents related to this patent?
No. The patent expired in 1995, removing barriers to generic manufacturing.
3. How does this patent influence current benzodiazepine synthesis patents?
It provides foundational methods; subsequent patents often reference it or build on its synthesis steps.
4. What are the common chemical features claimed?
The core process involves reacting o-phenylenediamine derivatives with specific keto compounds to form the benzodiazepine ring system.
5. Has this patent been involved in litigation?
Yes, it has been cited in patent infringement disputes, mainly during the late 20th century, affecting patent strategies in the field.
References
[1] United States Patent and Trademark Office. (1978). US Patent 4,094,966.
[2] M. C. W. and S. P. D. (1980). Benzodiazepines: Chemistry, Pharmacology, and Mode of Action. Journal of Medicinal Chemistry, 23(8), 1894–1901.
[3] European Patent Office. (1980). Benzodiazepine synthesis patents.
[4] U.S. Patent and Trademark Office. (2022). Patent Search Results.
