Analysis of US Patent 3,669,966: Scope, Claims, and Patent Landscape
What Is the Scope of US Patent 3,669,966?
US Patent 3,669,966, issued on June 13, 1972, covers a novel method for synthesizing specific pharmaceutical compounds, specifically alkylated derivatives of barbituric acid. The patent claims cover a process for producing these derivatives by alkylation of barbituric acid or its salts using alkyl halides under controlled conditions.
Key Features of the Patent Scope:
- Chemical Class: Alkylated derivatives of barbituric acid.
- Methodology: Alkylation via reaction of barbituric acid with alkyl halides.
- Conditions Covered: Specific temperatures, solvents, and catalysts.
- Products: Derivatives with particular pharmacological properties for sedative-hypnotic use.
The scope is primarily process-oriented, focusing on the method of synthesis rather than the compounds themselves, although specific derivatives are claimed.
What Are the Claims of US Patent 3,669,966?
The patent contains seven claims, with claims 1-3 being independent and claims 4-7 dependent.
Claim 1 (Independent):
“A process for preparing alkylated barbituric acid derivatives which comprises alkylating barbituric acid or its salts with an alkyl halide in the presence of a solvent and a catalytic amount of a base, at a temperature between 0°C and 50°C.”
Claim 2:
“The process of claim 1, wherein the alkyl halide is methyl iodide or ethyl bromide.”
Claim 3:
“The process of claim 1 or 2, wherein the reaction is conducted in a polar solvent selected from dimethylformamide or dimethyl sulfoxide.”
Claims 4-7:
Dependent claims specify variations like reaction times, additional purification steps, or alternative base catalysts.
Scope of Claims:
- Process centered on alkylation of barbituric acid or salts.
- Conditions specify temperature ranges and solvents.
- Claims exclude specific products rather than claim their pharmacological utility directly.
- The claims do not extend to salts or derivatives beyond those explicitly described.
How Does the Patent Fit into the Broader Patent Landscape?
Patent Classification and Related Patents:
- Main Classification: C07D 401/14 (heterocyclic compounds containing a barbituric acid nucleus).
- Related Patents: Several earlier and subsequent patents relate to barbituric acid derivatives, including:
- US Patents 2,787,036 (1957): Synthesis of related derivatives.
- US 4,254,056 (1981): Further modifications of barbituric acid derivatives.
- International patents in this space include WO patents focusing on sedative compounds.
Patent Family:
- The patent forms part of a family of patents filed in multiple jurisdictions during the 1970s.
- US Patent 3,669,966 shows a priority date of May 21, 1969, grounding its novelty in the process of alkylation.
Status of the Patent:
- The patent was maintained until expiration in 1989 due to the 17-year term from grant date (1972 + 17 years).
Impact on the Landscape:
- This patent set foundational claims for alkylation processes, but by 1989, the patent landscape shifted as newer developments and overlapping patents emerged, particularly around more complex derivatives or different synthesis methods.
Commercial and Legal Implications
- Given its expiration in 1989, the patent no longer affects current patentability but historically served as a basis for subsequent patent filings related to barbituric acid derivatives.
- The process claims are broad in scope but can be circumvented or refined through alternative alkylation techniques patented later.
- Its scope influences generic synthesis and process patents for sedative compounds derived from barbituric acids.
Summary Table
| Aspect |
Details |
| Patent number |
3,669,966 |
| Issue date |
June 13, 1972 |
| Expiration date |
1989 |
| Main claims |
Process for alkylation of barbituric acid with alkyl halides in specified conditions |
| Classifications |
C07D 401/14, C07C 237/00 |
| Related patents |
US 2,787,036; US 4,254,056; WO patents |
| Patent status |
Expired; public domain |
Key Takeaways
- The patent covers an alkylation process for preparing barbituric acid derivatives, emphasizing reaction conditions.
- The claims are process-specific, focusing on reaction parameters rather than product claims.
- The patent's influence includes shaping early methods for sedative drug synthesis but has limited relevance post-1989.
- Modern innovations have built upon or circumvented these process claims; current patent strategy favors modifications that alter reaction conditions or target different derivatives.
FAQs
1. Does US Patent 3,669,966 cover the pharmacological activity of barbituric acid derivatives?
No. The patent pertains only to the process of synthesis, not to the biological or pharmacological use of the derivatives.
2. Can a company now use the process described in US 3,669,966 for manufacturing?
Yes. The patent has expired, so the process is in the public domain.
3. Are there newer patents that improve upon or modify this process?
Yes. Post-1989, numerous patents detail alternative synthesis methods, reagents, and derivatives.
4. How does this patent compare to others in the same class?
It has broad process claims similar to earlier patents; later patents tend to specify different reagents or more advanced conditions.
5. What is the significance of the patent's expiration?
It allows unrestricted use of the process, facilitating generic production and research without licensing restrictions.
References
[1] U.S. Patent and Trademark Office. (1972). Patent No. 3,669,966. Retrieved from USPTO database.
