Detailed Analysis of the Scope and Claims of United States Patent 5,053,432
Introduction
United States Patent 5,053,432, titled "Naphthoquinone derivatives," is a significant patent in the field of pharmaceuticals, particularly for the treatment and prophylaxis of protozoal diseases. Here, we will delve into the scope, claims, and the broader patent landscape surrounding this invention.
Invention Overview
The patent describes naphthoquinone derivatives, specifically compounds of formula (I), which are useful for treating or preventing protozoal diseases such as malaria, theileriosis, and coccidiosis[1].
Chemical Structure and Variants
The compounds of formula (I) have specific structural requirements:
- (R_1) is hydrogen, and (R_2) can be selected from various groups including C1-6 alkoxy, aralkoxy, C1-6 alkyl-C1-6 alkoxy, phenyl substituted by halogen or C1-6 alkyl, halogen, and perhalo-C1-6 alkyl.
- Alternatively, (R_1) and (R_2) can both be C1-6 alkyl or phenyl.
- The variable (n) can be 0 or 1[1].
Isomers and Tautomeric Forms
The compounds can exist in cis and trans isomers, with the trans isomer typically being the predominant form. However, mixtures of both isomers in various ratios are also included within the scope of the invention. Additionally, these compounds may exist in tautomeric forms, which are also part of the invention[1].
Physiologically Acceptable Salts
The patent includes physiologically acceptable salts of these compounds, such as those formed with alkali metal cations (e.g., sodium or potassium) and organic bases (e.g., ethanolamine, diethanolamine, and N-methyl glutamine)[1].
Specific Applications
- Compounds of formula (IA) are particularly interesting as antimalarial and anticoccidial agents.
- Compounds of formula (IB) are of value as antitheilerial agents and as intermediates in the preparation of compounds of formula (IA)[1].
Synthesis Methods
The patent outlines various methods for preparing these compounds, including the use of Hooker oxidation and the preparation of bioprecursors. The synthesis involves reacting starting materials with specific reagents and solvents, such as a mixture of water and acetonitrile, to achieve desired cis to trans ratios[1].
Claims Scope
The claims of the patent are detailed and specific:
- Claim 1 covers the trans compound of the formula (I).
- Claim 2 includes physiologically acceptable salts of the trans compound of the formula (I)[5].
Patent Landscape
Related Patents
Other patents, such as US6649659B1 and US7847127B2, are related to the synthesis and pharmaceutical compositions of atovaquone, a specific compound covered under the broader scope of US5053432A. These patents describe improved methods for producing atovaquone, including microfluidization to enhance bioavailability and novel intermediates for its synthesis[2][4].
Challenges in Broad Claims
The patent landscape highlights the importance of carefully defining the claim scope. Broad claims, while offering broader protection, are more difficult to get granted and easier to invalidate. The claim scope must be anchored to the embodiments disclosed in the specification to avoid invalidation grounds such as the abstract idea exception and failure to meet the written description requirement[3].
Industry Impact
The compounds and methods described in US5053432A have significant implications for the treatment of protozoal diseases. Atovaquone, a key compound, is used in therapies for diseases like malaria and Pneumocystis carinii pneumonia. The development of novel synthesis processes and pharmaceutical compositions has improved the efficacy and availability of these treatments[2][4].
Key Takeaways
- Specific Compounds: The patent covers specific naphthoquinone derivatives useful for treating protozoal diseases.
- Isomers and Salts: Includes both cis and trans isomers and physiologically acceptable salts.
- Synthesis Methods: Outlines various synthesis methods, including Hooker oxidation and bioprecursor preparation.
- Related Patents: Other patents focus on improved synthesis and pharmaceutical compositions of atovaquone.
- Claim Scope: Careful definition of claim scope is crucial to avoid invalidation.
FAQs
Q: What are the primary applications of the compounds described in US5053432A?
A: The compounds are primarily used for the treatment or prophylaxis of protozoal diseases such as malaria, theileriosis, and coccidiosis.
Q: What is the significance of cis and trans isomers in this patent?
A: The patent includes both cis and trans isomers, with the trans isomer being the predominant form, but mixtures of both are also covered.
Q: How are the physiologically acceptable salts formed?
A: These salts are formed with alkali metal cations or organic bases such as ethanolamine and diethanolamine.
Q: What is the role of Hooker oxidation in the synthesis process?
A: Hooker oxidation is a method used to prepare compounds of formula (IA) from the corresponding compounds of formula (IB).
Q: How does the patent landscape impact the validity of broad claims?
A: Broad claims are more difficult to get granted and easier to invalidate due to potential issues like the abstract idea exception and failure to meet the written description requirement.
Cited Sources:
- US5053432A - Naphthoquinone derivatives - Google Patents
- US6649659B1 - Atovaquone pharmaceutical compositions - Google Patents
- The Importance of Getting the Claim Scope Right in a US Patent Application - Rimon Law
- US7847127B2 - Process for preparation of atovaquone and novel intermediates thereof - Google Patents
- Claims for Patent: 5053432 - DrugPatentWatch
