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Patent landscape, scope, and claims: |
United States Patent 6,034,239 (Drug): Scope, Claims, and US Patent Landscape
What is the core claim scope of US 6,034,239?
US Patent 6,034,239 claims a family of melatonin-receptor binding compounds defined by a generalized chemical scaffold (Formula I in claim 1) and extremely broad substituent definitions, including salts, plus downstream process, composition, and method-of-treatment claims.
Claim 1: Formula-wide coverage (most important independent claim)
Claim 1 covers:
- A compound of the formula (structure shown as ##STR74## in the claim)
- with these variable definitions:
- R1: optionally substituted hydrocarbon group, optionally substituted amino group, or optionally substituted heterocyclic group
- R2: hydrogen or optionally substituted hydrocarbon group
- R3: hydrogen, optionally substituted hydrocarbon group, or optionally substituted heterocyclic group
- X: CHR4, NR4, O, or S
- where R4: hydrogen or optionally substituted hydrocarbon group
- Y: C, CH, or N
- with a restriction: when X is CH2, Y is C or CH
- bonding: “represented by a single bond or a double bond” between the relevant ring positions (the claim uses “.... represented a single bond or a double bond”)
- ring A: optionally substituted 5- to 7-membered oxygen-containing heterocycle
- ring B: optionally substituted benzene ring
- m: integer 1 to 4
- includes salts of the compounds
Practical consequence: Claim 1 is a broad Markush-style scope around (i) ring system variability (ring A size and hetero composition via “oxygen-containing heterocycle”), (ii) aromatic substitution via ring B, and (iii) linker/hetero-atom variability through X/Y and the bond selection.
How broad are the substituent ranges in the independent chemical coverage?
Claim 2 is a dependency that expands and clarifies the substituent universe for R-group and ring substituents, using large combinatorial ranges.
Claim 2: Expanded Markush sets for R1/R2/R3/R4 and ring A/ring B substitution
Claim 2 states the compound of claim 1 where:
-
R1 can be one of:
1) C1-6 alkyl / C2-6 alkenyl / C2-6 alkynyl / C3-6 cycloalkyl / C6-14 aryl, substituted with 1 to 5 groups from a long list (halogen, nitro, cyano, hydroxy, halo-alkyl, alkoxy, amino, alkylamino, carboxyl, alkyl-carbonyl, alkoxy-carbonyl, carbamoyl, alkyl-carbamoyl, aryl-carbamoyl, aryl, aryloxy, halo-alkyl-carbonylamino)
2) an amino group substituted with 1 or 2 substituents from similarly wide sets (alkyl/alkenyl/alkynyl/cycloalkyl/aryl), each substituted with up to 1 to 5 groups from the same list
3) a 5- to 14-membered heterocycle with 1 to 3 hetero atoms (N/O/S), substituted with 1 to 5 substituents from an even larger enumerated list (including sulfonyl/sulfamoyl/phosphono/amidino/imino/mercapto variants, arylthio, sulfinyl, etc.)
-
R2 can be:
- hydrogen or
- C1-6 alkyl / C2-6 alkenyl / C2-6 alkynyl / C3-6 cycloalkyl / C6-14 aryl, each optionally substituted with up to 1 to 5 groups from the same broad set
-
R3 can be:
- hydrogen or
- the same wide hydrocarbon/aryl ranges as R2, optionally substituted
- or a 5- to 14-membered heterocycle similarly substituted
-
R4 can be:
- hydrogen or
- a wide substitutable hydrocarbon/aryl range (same “1 to 5 substituents” logic)
-
ring A:
- a 5- to 7-membered oxygen-containing heterocycle
- has 1 to 3 additional hetero atoms selected from N/O/S
- ring A can be substituted by 1 to 4 substituents from an enumerated list that overlaps strongly with the R-group substituent universe and includes small functional groups (oxo, amino, nitro, cyano, hydroxy, etc.) and broader groups (sulfo/phosphono/sulfamoyl and aryl/alkyl groups with their own substitutions)
-
ring B:
- benzene ring substituted by 1 or 2 substituents selected from a list including halogen, alkyl/alkenyl/alkynyl/cycloalkyl/aryl (each optionally substituted with 1 to 5 groups), amino variants, alkoxy variants, and alkylenedioxy.
Practical consequence: Claim 2 makes the covered chemical space extremely large. Many “druglike” aryl, heteroaryl, and substituted alkyl/functionalized substituents fall within the enumerated sets.
Which claim elements narrow the scaffold enough to define a more specific patent “center of gravity”?
Despite the large Markush space, the claim framework still restricts the core scaffold tightly via:
- Ring A identity class: oxygen-containing heterocycle, 5 to 7-membered, with specified hetero-atom boundaries (and optional substitution).
- Ring B identity class: benzene ring with up to two substituents.
- X/Y constraint logic: X can be CHR4/NR4/O/S and Y is C/CH/N with a specific conditional constraint when X is CH2.
- m = 1 to 4: limits the number of a specific scaffold unit within the depicted formula series.
These elements typically anchor design-arounds: altering the oxygen-containing heterocycle class, ring size, or the X/Y relationship would often fall outside coverage.
How does the patent capture specific exemplified compounds?
The specification-to-claim bridge appears through dependent claims that recite particular named compounds.
Selected exemplified compounds explicitly claimed
The patent includes several “wherein the compound is …” dependents that identify exact structures by name:
- Claim 25: (S)-N-[2-(1,6,7,8-tetrahydro-2H-indeno[5,4-b]furan-8-yl)ethyl]propionamide
- Claim 26: N-[2-(1,6,7,8-tetrahydro-2H-furo[3,2-e]indol-8-yl)ethyl]propionamide
- Claim 27: N-[2-(1,6,7,8-tetrahydro-2H-furo[3,2-e]indol-8-yl)ethyl]butyramide
- Claim 28: N-[2-(7-phenyl-1,6-dihydro-2H-indeno[5,4-b]furan-8-yl)ethyl]propionamide
- Claim 29: N-[2-(7-phenyl-1,6-dihydro-2H-indeno[5,4-b]furan-8-yl)ethyl]butyramide
Practical consequence: The named compounds show the likely internal “reference set” from which the Markush ranges were drawn.
What scope does the patent set for processes and manufacturing?
Claim 30: Synthetic route via acylation and optional reduction/alkylation
Claim 30 covers:
- A process for producing the claim 1 compound by:
- reacting a compound of formula (i) (##STR78##) or formula (ii) (##STR79##)
- with R1 COOH (or salt or reactive derivative)
- and if necessary, subjecting the resultant compound to reduction and/or alkylation
Claim 31: Cyclization route
Claim 31 covers:
- subjecting a compound of formula (##STR80##) to cyclization
- where:
- R5 is hydrogen, halogen, optionally substituted hydrocarbon, optionally substituted alkoxy, hydroxy, nitro, cyano, or optionally substituted amino
- L is a leaving group
- optionally followed by reduction
Claim 41: Manufacturing pharmaceutical composition
Claim 41 covers:
- selecting a compound or pharmaceutically acceptable salt of claim 1
- admixing with a pharmaceutically acceptable carrier
What scope does the patent set for formulations and medical use?
Composition claim
- Claim 34: pharmaceutical composition containing:
- a compound of claim 1 or its pharmaceutically acceptable salt
- plus a pharmaceutically acceptable carrier
Receptor-binding-defined coverage
- Claim 35: composition where the compound/salt has binding affinity for melatonin receptor.
Method-of-use claims
- Claim 36: method for treating or preventing diseases related to melatonin action in mammals
- admin of a therapeutically effective amount of the composition of claim 35.
- Claim 37: regulates circadian rhythm
- Claim 38: regulates sleep-awake rhythm
- Claim 39: treats/prevents time zone change syndrome
- Claim 40: treats/prevents sleep disorders
Practical consequence: Claim 35 functions as a receptor-mechanism link; claims 36 to 40 convert that into broad therapeutic indications tied to melatonin-related physiology.
What are key structural subscopes that narrow the claim parameters?
The patent includes a set of narrowing dependents (useful for claim charting during infringement/validity analysis):
X / Y / bond and ring parameter narrowing
- Claim 12: X is CHR4
- Claim 13: X is CHR4 and the indicated bond (represented by “....”) is a single bond
- Claim 14: Claim 13 plus X is CH2
- Claim 15: X is NR4
- Claim 16: Y is C or CH
- Claim 17: Y is CH
- Claim 18: m is 2
- Claim 19: ring A is tetrahydrofuran
- Claim 20: ring A is unsubstituted
- Claim 21: ring B is unsubstituted
R-group narrowing
- Claim 5: R1 is restricted to one of:
- optionally substituted C1-6 alkyl
- optionally substituted C3-6 cycloalkyl
- optionally substituted C2-6 alkenyl
- optionally substituted C6-14 aryl
- optionally substituted mono- or di-C1-6 alkylamino
- optionally substituted C6-14 arylamino
- optionally substituted 5- or 6-membered nitrogen-containing heterocyclic group
- Claim 6: R1 is optionally halogenated C1-6 alkyl
- Claim 7: R2 is hydrogen or optionally substituted C1-6 alkyl
- Claim 8: R2 is hydrogen
- Claim 9: R3 is hydrogen or optionally substituted hydrocarbon group
- Claim 10: R3 is hydrogen
- Claim 11: R4 is hydrogen or optionally substituted C1-6 alkyl
Ring A′ and additional structural variants
- Claim 4: compounds where ring A′ is an optionally substituted oxygen-containing heterocycle and n is 0 to 2 with additional “---- and .... independently single or double bonds”
- Claim 22: n is 0 or 1
- Claim 3: includes a secondary Markush variant (##STR75##) where R4′ is optionally substituted hydrocarbon
- Claim 32-33: additional formula variants with Xa/Ya and different positioning constraints
Example-oriented additional subscaffold claims
- Claim 23: another formula (##STR77##) with constraints including:
- R1b = C1-6 alkyl
- X′ = CH2, NH, or NCHO
- R3a = hydrogen atom or phenyl
- Ea = CH2CH2, CH=CH, CH2O, CH=N, CONH, or CH2NH
- na = 0 or 1
- ring A″ is 5- or 6-membered oxygen-containing heterocycle optionally substituted by 1 or 2 C1-6 alkyl optionally substituted by hydroxy
- ring B′ is benzene ring optionally substituted by halogen
- Claim 24: claim 23 plus “....” is a single bond and X′ is NH
How does this claim strategy shape the US patent landscape?
The patent presents a classic breadth stack:
1) Core chemical Markush (claim 1)
2) Substituent expansion dependency (claim 2) that enlarges the chemical universe without changing the core scaffold.
3) Narrowed dependents that track specific structure parameters (X/Y/bond/m/ring substitution) useful for either:
- asserting infringement against specific analogs, or
- tightening validity if broad combinations are later attacked.
4) Named exemplars (claims 25-29) that anchor the claim family to concrete structures.
5) Process claims (claims 30-31) tied to generic intermediates and transformations, then formulation manufacturing (claim 41).
6) Mechanism-linked composition and method claims (claims 34-40) using melatonin receptor binding affinity and circadian/sleep/time-zone indications.
Business implication: A generic or follow-on developer facing this patent would typically need to assess:
- whether their compound falls outside the ring A class and X/Y structural logic (scaffold design-around),
- whether their receptor-binding and therapeutic use claims create separate infringement risk even if chemical structure overlaps only partially,
- and whether their route of synthesis triggers process claim coverage (if manufacturing is in scope).
Claim coverage map (quick reference)
| Claim bucket |
Claims |
What it covers |
Main risk driver for competitors |
| Core compound |
1 |
Formula-wide scaffold with X/Y/bond/rings/m |
Scaffold match to ring A/ring B and X/Y constraints |
| Expanded substituents |
2 |
Broad combinatorial options for R1/R2/R3/R4 and ring substitution |
Analog design still likely within enumerated substituent sets |
| Specific subscaffold constraints |
3-33 |
Variants on R-group/position/bond/ring A/ring A′/n/other substitutions |
Narrow sub-parameter overlap |
| Named compounds |
25-29 |
Exact exemplified amides |
Direct hit risk if any marketed compound matches |
| Synthesis routes |
30-31 |
Reaction of defined intermediates with R1 COOH; cyclization |
Manufacturing route exposure |
| Composition and indications |
34-41 |
Melatonin receptor binding affinity composition + mammalian melatonin-action methods |
Use-based infringement exposure even for partial chemical overlap |
What is missing for a true US patent landscape build?
A “patent landscape” normally requires:
- citation to related patents,
- prosecution history for priority and claim amendments,
- expiration status by term and any PTA/PTE,
- and invalidity/voidance events (office actions, lawsuits, terminal disclaimers, reexaminations).
No such bibliographic and legal-history data for US 6,034,239 is present in the input.
Given the constraint to provide a complete and accurate landscape, the analysis below is limited to claim-scope and internal logical boundaries visible from the claim text provided.
Key Takeaways
- US 6,034,239 is a melatonin-receptor small-molecule family patent anchored by a ring A oxygen-containing heterocycle (5- to 7-membered), a benzene ring (ring B), and specific X/Y structural logic, with m = 1 to 4.
- Claim 1 sets the scaffold, while claim 2 multiplies substituent coverage through very broad enumerated Markush sets for R1/R2/R3/R4 and ring A/ring B substitution.
- The patent covers not only compounds but also pharmaceutical compositions with melatonin receptor binding affinity and methods for circadian rhythm and sleep-related indications.
- Process claims (claims 30-31) and manufacturing a pharmaceutical composition (claim 41) add enforcement vectors tied to production and formulation steps.
- The named exemplars (claims 25-29) indicate specific amide analogs within the Markush space, increasing direct-hit risk if any candidate matches those exact structures.
FAQs
1) Is claim 1 the primary infringement target?
Yes. Claim 1 defines the broadest chemical scope via the general formula and the core ring/X/Y/m structural constraints.
2) Does claim 2 broaden the compounds covered beyond claim 1?
Yes. Claim 2 is a dependency that supplies expanded definitions and allowable substitutions for R1/R2/R3/R4 and ring substitutions without changing the underlying scaffold boundary conditions.
3) Can infringement occur through method-of-use even if chemical structure is borderline?
Yes. The patent includes composition and method claims (claims 34-40) tied to melatonin receptor binding affinity and therapeutic indications.
4) Are specific exemplified molecules separately claimed?
Yes. Claims 25-29 recite exact compounds by name, providing additional paths for enforcement if any candidate matches those structures.
5) Do process claims add a separate risk in manufacturing?
Yes. Claims 30-31 cover generic synthetic steps using defined intermediate classes and transformations, plus claim 41 for formulation manufacturing via admixing with a carrier.
References
[1] United States Patent 6,034,239, claims 1-41 (provided claim text).
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