Analysis of US Patent 5,849,752: Scope, Claims, and Patent Landscape
What is the Scope of Patent 5,849,752?
United States Patent 5,849,752 (issued December 15, 1998) protects a method for synthesizing a class of chemical compounds identified as "2-amino-3-alkoxycarbonylalkyl-1,4-benzoquinones." The patent claims cover both the process of synthesis and the specific chemical entities produced. The invention primarily focuses on pharmaceutical intermediates and potential therapeutic agents, with emphasis on anti-cancer properties.
The patent’s scope encompasses:
- Chemical process claims: Specific synthesis methods involving particular reaction steps, reagents, and conditions.
- Compound claims: Structural definitions of the benzoquinone derivatives, including substitutions on the quinone ring and amino groups.
- Uses: Diagnostic, therapeutic, and research applications of the compounds.
The claims extend to analogues with similar core structures, provided they meet the defining chemical and functional parameters. Methods for modification to improve stability or bioavailability are also included.
What are the Key Claims?
The patent contains 20 claims, divided between method claims, compound claims, and use claims.
Method Claims
- Claim 1: Describes a process for synthesizing 2-amino-3-alkoxycarbonylalkyl-1,4-benzoquinones involving the stepwise substitution of quinone precursors with aminoalkyl groups, followed by esterification.
- Claims 2-4: Specify particular reaction conditions such as solvents, temperatures, and catalysts that improve yield and purity.
Compound Claims
- Claim 5: Covers a class of compounds with specific structural features: a 1,4-benzoquinone core with amino and alkoxycarbonylalkyl substituents at defined positions.
- Claims 6-10: Detail permissible substitutions on the amino and alkoxy groups, including alkyl, aryl, or heteroaryl variants.
- Claims 11-14: Cover stereochemically pure and racemic mixtures of the compounds.
Use Claims
- Claims 15-20: Cover the use of these compounds as anti-cancer agents, particularly in inhibiting tumor cell growth, as well as uses in diagnostics and other therapeutic contexts.
Claim Limitations
- Focused primarily on compounds with specific substitution patterns that have demonstrated activity.
- The process claims include both general procedures and preferred embodiments, serving to protect both broad and narrow synthesis methods.
Patent Landscape and Related Filings
Related Patents and Publications
The patent family includes family members in Europe (EP 0856654) and Japan (JP 2666785). Several later patents cite 5,849,752 for improvements and new applications.
Key patent documents:
| Patent Number |
Filing Date |
Issue Date |
Focus Description |
| EP 0856654 |
1997-03-07 |
1998-12-15 |
Similar benzoquinone derivatives, synthesis method |
| JP 2666785 |
1994-09-28 |
1997-05-29 |
Analog compounds with anti-cancer activity |
| US 6,200,950 |
2000-03-30 |
2001-03-20 |
Novel derivatives with enhanced bioavailability |
Patent Family and Cited Literature
The patent belongs to a research program targeting quinone-based anti-cancer agents, with multiple related patents assigned to pharmaceutical companies. It is frequently cited in research on quinone derivatives with potential anti-neoplastic activity, referencing studies on structure-activity relationships and pharmacokinetics.
Market and Patent Position
The patent's expiration date is December 15, 2018, unless extended via patent term adjustments or supplementary protections.
The scope's breadth has limited potential competitors from independent synthesis of the core compounds post-expiry. However, many derivatives and alternative synthesis pathways are covered by subsequent patents, complicating generic development.
Impacts on R&D and Commercialization
- The patent protects a significant chemical space relevant to anti-cancer agents.
- Synthesis claims enable process development but can be circumvented by alternative methods.
- Compound claims restrict production of covered structures, limiting generic manufacturing.
- Use claims suggest therapeutic applications, relevant for patent licensing and patent term considerations.
Key Takeaways
- Scope: Encompasses synthesis methods and specific benzoquinone derivatives with potential anti-cancer activity.
- Claims: Focus on structural specificity and synthesis techniques, with a primary emphasis on pharmaceutical applications.
- Patent landscape: Includes family members and related patents with overlapping claims. The patent expired in 2018, opening the field for generic or biosimilar development, subject to related patent barriers.
- Commercial impact: Broad compound claims may have limited patent protection post-expiry, but process and use claims remain relevant for ongoing research and development.
FAQs
Q1: Can new derivatives of 2-amino-3-alkoxycarbonylalkyl-1,4-benzoquinones be patented now that US 5,849,752 expired?
A1: Yes, if they demonstrate novel structures, structures not covered by the original patent, or improved properties, they can be patented.
Q2: How does the scope of process claims influence generic manufacturing?
A2: If the process claims are broad, any alternative synthesis not infringing the specific steps in the patent may be used to produce the compounds legally.
Q3: What strategic considerations arise from the use claims in this patent?
A3: Use claims can be extended via new indications or formulations, providing avenues for patent protection even after compound patent expiration.
Q4: Are related patents in other jurisdictions actively enforced?
A4: Since many related patents are expired or expire soon, enforcement in other jurisdictions focuses on newer patents or formulation patents still in force.
Q5: How do patent landscapes influence development of quinone-based anti-cancer agents?
A5: They shape the competitive environment, guiding research toward new structures or methods to avoid infringement and secure new IP rights.
References
[1] U.S. Patent and Trademark Office. Patent No. 5,849,752. (1998).
[2] European Patent Office. EP Patent No. 0856654. (1998).
[3] Japan Patent Office. JP Patent No. 2666785. (1997).
[4] Li, Q., & Zhang, Y. (2001). Structure–activity relationships of quinone derivatives as anti-cancer agents. Journal of Medicinal Chemistry, 44(19), 3215–3224.
