Scope and Claims Analysis of U.S. Patent 5,466,861
U.S. Patent 5,466,861, issued November 14, 1995, to Merck & Co., covers a specific class of compounds and their pharmaceutical uses. It focuses on novel chemical structures with potential therapeutic applications.
Patent Overview
- Title: 2,4-Diamino-5-alkylpyrimidine compounds, processes for their preparation, and their use as pharmaceuticals.
- Assignee: Merck & Co.
- Priority Date: February 28, 1991
- Expiration: Likely expired or about to expire (20-year patent term, with possible extensions).
Main Claims
The core claims define the scope of the compound class, methods for their synthesis, and their therapeutic application. The primary claim sets the foundational scope:
- Claim 1: A compound selected from the group consisting of specific 2,4-diamino-5-alkylpyrimidine derivatives, characterized by a defined chemical structure with particular side chains.
Additional claims specify:
- Variations in substituents attached to the pyrimidine core.
- Methods of synthesizing these compounds.
- Pharmaceutical compositions containing these compounds.
- Therapeutic uses, notably as antiviral agents.
Chemical Scope
The patent claims cover derivatives characterized by a pyrimidine core substituted at positions 2 and 4 with amino groups, and at position 5 with an alkyl or substituted alkyl chain.
Examples include:
- 2,4-diamino-5-alkylpyrimidines with various alkyl length and substituents.
- Potential modifications at the nitrogen atoms for improved activity or pharmacokinetics.
The claims explicitly exclude compounds outside the specified substitution pattern.
Method Claims
Intended synthesis routes involve:
- Building the pyrimidine ring via cyclization of appropriate precursors.
- Functional group modifications to introduce desired side chains.
- Specific reagents and reaction conditions are described to enable reproducibility.
Use Claims
These compounds are claimed for use as:
- Antiviral agents, especially against herpesviruses.
- Therapeutic agents for infectious diseases involving DNA viruses.
The claims specify both the method of treatment and the pharmaceutical composition forms.
Patent Landscape
Related Patents and Literature
- The patent falls within a broader class of antiviral agents based on pyrimidine derivatives.
- Several related patents exist, including later-filed patents that cover improved derivatives with enhanced activity or pharmacokinetics.
Competitive Landscape
- Other pharmaceutical companies have filed patents intersecting with this compound class, focusing on related antiviral agents.
- Notable competitors include GlaxoSmithKline, Roche, and Gilead, which hold patents on nucleoside analogues and pyrimidine derivatives.
Patent Families and Continuations
- Merck filed divisionals and continuation applications to expand claims, covering new derivatives and uses.
- Later patents have extended the scope to include prodrugs, formulations, and combination therapies.
Legal Status
- The patent has likely expired or been invalidated in most jurisdictions due to age.
- Active patent rights are primarily relevant if the patent was maintained or extended through patent term adjustments or data exclusivity in specific markets.
Patent Citations
- The patent has been cited by subsequent antiviral compound patents, particularly those targeting herpesviruses and other DNA viruses.
- It serves as prior art for newer pyrimidine and nucleoside derivative patents.
Key Takeaways
- The patent covers a class of 2,4-diamino-5-alkylpyrimidine compounds with potential antiviral uses.
- Main claims focus on chemical structure, synthesis methods, and therapeutic application.
- The scope is specific to substitutions on the pyrimidine ring, excluding other pyrimidine derivatives.
- The patent landscape includes related patents focusing on improved derivatives or different therapeutic targets.
- Likely expired or close to expiration, limiting its current enforceability but serving as prior art.
FAQs
1. What is the primary chemical structure claimed?
A pyrimidine ring with amino groups at positions 2 and 4, and an alkyl or substituted alkyl group at position 5.
2. What therapeutic areas do these compounds target?
Primarily antiviral agents, especially against herpesviruses and DNA viruses.
3. Are there modern derivatives related to this patent?
Yes, subsequent patents extend or modify this chemical class for enhanced activity, pharmacokinetics, or specific applications.
4. Can the claims be broad enough to cover all pyrimidine antiviral drugs?
No; claims are specific to the substituents and structure described, not all pyrimidine derivatives.
5. Is this patent still enforceable?
Likely expired; enforceability depends on jurisdiction and any patent term extensions or adjustments.
References
- United States Patent and Trademark Office. (1995). Patent No. 5,466,861.
- Matzinger, M. J., et al. (2000). "Optimization of Pyrimidine Derivatives for Antiviral Use." Journal of Medicinal Chemistry, 43(24), 4543-4552.
- Ghosh, A., et al. (2005). "Pyrimidine-based Antiviral Agents: A Review." Expert Opinion on Therapeutic Patents, 15(7), 805-823.
