Executive summary
US Patent 7,511,041 claims broad structural genus coverage to fused azolepyrimidine derivatives defined by a general formula (I), including tautomers, stereoisomers, and salts, plus dependent scope that narrows to specific sub-structures and exemplified compounds. Independent coverage is anchored on an azolepyrimidine scaffold with tightly defined heteroatom connectivity (notably the Y2═Y3 bond condition and the X substituent), while R-group substituent definitions are extremely expansive, spanning broad aryl/heteroaryl options and diverse functionalized substituents for R1 and R2. Dependent claims explicitly cover medicaments and method-adjacent functional positioning as PI3K inhibitors, including PI3K-γ inhibitors. Practically, the claim set supports infringement theories both for exact structure matches (including salts and stereoisomers) and for near-miss competitors that fit the formula constraints and replace only R-group decorations within the permitted ranges.
US Patent 7,511,041 scope and claims: fused azolepyrimidine derivatives and PI3K-γ inhibitor medicaments
US 7,511,041 is drafted as a core genus composition-of-matter patent: claim 1 covers an enormous chemical space via a formula (I), then claims 2–8 refine sub-genus definitions and claim 8 enumerates multiple specific exemplars. Claims 9–12 extend coverage to medicaments containing the claimed compound and specify PI3K inhibitor / PI3K-γ inhibitor use.
What is the claim architecture and how broad is the independent claim?
Claim 1 is the key coverage vehicle. It covers:
- A compound of formula (I)
- Including tautomeric or stereoisomeric forms
- And salts
- With multiple structural constraints:
- X: “CR5R6 or NH”
- Y1: “CR3 or N”
- The bond between Y2 and Y3:
- if double bond: Y2 and Y3 independently are CR4 or N
- if single bond: Y2 and Y3 independently are CR3R4 or NR4
- Z1–Z4: independently CH, CR2 or N
- substituent variables R1 and R2 and ring/functional substituent allowances
- R3 (often hydrogen in later dependents), R4, R5, R6 are defined in the claim
The breadth comes from two design choices:
- The scaffold is formula-defined, which prevents full “any-structure” coverage, but
- The substituent and allowed ring substituent vocabularies are highly permissive, especially for R1 and R2.
Claim 1: the binding scaffold constraints (what you cannot change)
Across claim 1, the following are “hard gates” that drive whether an accused compound falls in or out:
Hard gate 1: X
- Must be either CR5R6 (alkyl or halogen substituted carbon) or NH.
Hard gate 2: Y1
Hard gate 3: Y2═Y3 bond condition
- If Y2═Y3 is double: both ends are independently CR4 or N.
- If Y2═Y3 is single: both ends are independently CR3R4 or NR4.
This makes the aza/alkene topology part of the infringement determination. Competitors that change the bond order or the allowed valences for Y2/Y3 are more likely to exit the claim.
Hard gate 4: Z1–Z4
- Each of Z1–Z4 can be CH, CR2 or N.
This controls substitution pattern on the fused system.
Claim 1: why R1 and R2 create wide genus coverage
The widest path to infringement is usually through R1 and R2 definitions.
R1 definition (claim 1)
R1 spans:
- aryl optionally substituted by R11 (halogen/nitro/hydroxy/cyano/carboxy/amino and many protected/functional amines, sulfonamides, etc.)
- C3-8 cycloalkyl optionally substituted
- C1-6 alkyl optionally substituted by aryl/heteroaryl/alkoxyaryl/aryloxy/heteroaryloxy and halogens and additional functional groups
- 3–15 membered mono- or bi-cyclic heterocyclic ring (saturated/unsaturated), optionally substituted and containing 1–3 heteroatoms (N/O/S)
- with R11 representing a long list of functional groups
This is broad enough to capture a wide range of medicinal chemistry substitution patterns typical for PI3K inhibitors (heteroaryl pendant groups, protected amines, sulfonamides, nitriles, halogenation patterns, etc.).
R2 definition (claim 1)
R2 is also broad and includes:
- hydroxy, halogen, nitro, cyano, amines
- multiple heterocycle and aryl options
- acyloxy/amine-acyloxy variants
- “—C(O)—R20” fragments where R20 again permits hydroxy/amino/alkylamino, heterocycles, benzyl, etc.
- substituent definitions include both direct ring substituents and carbonyl/urea-like motifs
In combination with R1, claim 1 can cover both “head” and “tail” decorations that change potency or kinase selectivity while keeping the core fused scaffold.
Claim 1 composition signals: salts, stereoisomers, tautomers
Infringement can be asserted for:
- specific stereoisomers if a marketed product or candidate has an isomer that fits the formula variables
- tautomeric forms and salt forms if the chemical in question is in the claim-defined equivalence class
What dependent claims narrow US 7,511,041 coverage, and how do they affect infringement risk?
Dependent claims 2–7 progressively constrain the formula (I) parameters (X, Y1, Y2/Y3, Z positions, and R-group selections). Claim 8 then narrows further by listing specific compounds.
Claim 2: tight substitution pattern subset of the genus
Claim 2 sets:
- X: CR5R6 or NH
- Y1: N
- Y2 and Y3: CR3R4 with Y2═Y3 as a single bond
- Z4: CH
- Z1–Z3: independently CH, CR2 or N
- R1 and R2: narrowed to specific allowed selections (still broad, but more constrained than claim 1)
- and sets R3, R4, R5, R6 as hydrogen
Effect: claim 2 is narrower by forcing hydrogen at R3–R6, and enforcing specific bond/single-bond connectivity between Y2 and Y3.
Claims 3–5: more distinct positional constraints for scaffold mapping
These dependent claims refine Z positions and/or allowed substituents:
- Claim 3 keeps Y2═Y3 as single and sets Z4: CH, then gives narrower lists for R1
- Claim 4 changes Z positions and restricts R3–R6 to hydrogen while giving different allowed sets for R1 and R2
- Claim 5 changes which Z positions are CH and which are CH/CR2, while again narrowing R1 lists and keeping R3–R6 as hydrogen
From an infringement perspective, the key value is practical:
- if a competitor product fits only one structural pattern among these Z-position configurations, claim coverage will hinge on that exact mapping.
Claims 6 and 7: targeted sub-genus blocks with minimal remaining degrees of freedom
- Claim 6 narrows R1 to a short enumerated subset (e.g., 3H-imidazo[4,5-b]pyridinyl, benzimidazolyl pyridyl substituted variants, 1,3-thiazolyl substituted variants), and R2 to halogen or select heteroaryl substituent classes.
- Claim 7 likewise narrows R1 to the same targeted set, keeps R3–R6 hydrogen, but refines which Z positions are CH versus CR2.
These claims are less likely to be “accidentally” infringed, but they are valuable for fallback coverage if the independent genus is avoided by a design-around.
What specific compounds are explicitly claimed in US 7,511,041 claim 8?
Claim 8 provides an explicit list of specific fused azolepyrimidine derivatives. The listed compounds share a common motif based on “7,8-dimethoxy-2,3-dihydroimidazo[1,2-c]quinazolin” fused scaffold and a pyridine-containing vinyl/ethylenol or nicotinamide substitution pattern, plus multiple functional variants (methoxy, dimethoxy, bromo, trifluoromethyl, morpholine, hydroxy, tetrazolylmethoxy, various carboxylic acid/amide forms).
Representative enumerated compounds include:
- N-(7,8-dimethoxy-2,3-dihydroimidazo[1,2-c]quinazolin-5-yl)nicotinamide
- 2-(7,8-dimethoxy-2,3-dihydroimidazo[1,2-c]quinazolin-5-yl)-1-pyridin-3-ylethyleno
- N-(7,8-dimethoxy-2,3-dihydroimidazo[1,2-c]quinazolin-5-yl)-1H-benzimidazole-5-carboxamide
- N-{5-[2-(7,8-dimethoxy-2,3-dihydroimidazo[1,2-c]quinazolin-5-yl)-1-hydroxyvinyl]pyridin-2-yl}acetamide
- ({5-[2-hydroxy-2-pyridin-3-ylvinyl]-7-methoxy-2,3-dihydroimidazo[1,2-c]quinazolin-8-yl}oxy)acetic acid
- 4-({5-[2-hydroxy-2-pyridin-3-ylvinyl]-7-methoxy-2,3-dihydroimidazo[1,2-c]quinazolin-8-yl}oxy)butanoic acid
- ({5-[2-hydroxy-2-pyridin-3-ylvinyl]-7-methoxy-2,3-dihydroimidazo[1,2-c]quinazolin-8-yl}oxy)acetonitrile
- 2-[7-methoxy-8-(2H-tetrazol-5-ylmethoxy)-2,3-dihydroimidazo[1,2-c]quinazolin-5-yl]-1-pyridin-3-ylethyleno
- 2-[8-(2-hydroxyethoxy)-7-methoxy-2,3-dihydroimidazo[1,2-c]quinazolin-5-yl]-1-pyridin-3-ylethylenol
- N-(8-bromo-2,3-dihydroimidazo[1,2-c]quinazolin-5-yl)nicotinamide
- N-(8-methoxy-2,3-dihydroimidazo[1,2-c]quinazolin-5-yl)-1H-benzimidazole-5-carboxamide
- N-[8-(trifluoromethyl)-2,3-dihydroimidazo[1,2-c]quinazolin-5-yl]-1H-benzimidazole-5-carboxamide
- N-(7-fluoro-2,3-dihydroimidazo[1,2-c]quinazolin-5-yl)-1H-benzimidazole-5-carboxamide
- N-(9-methoxy-2,3-dihydroimidazo[1,2-c]quinazolin-5-yl)-1H-benzimidazole-5-carboxamide
This enumeration matters because it gives:
- clear “roadmap” chemistry for claim construction
- a concrete set for assessing design-around feasibility (substituent swaps that stay within claim ranges versus swaps that change the scaffold substitution pattern).
What do the medicament claims cover: PI3K inhibitors and PI3K-γ inhibitors in US 7,511,041?
Claims 9–12 are formulation-adjacent in the strict legal sense: they are composition-of-matter medicament claims, not method-of-treatment claims, but they still include functional limitations.
Claim 9: medicament using the claimed compound
- A medicament with the fused azolepyrimidine derivative (or tautomer/salt) as active ingredient.
Claim 10: medicament with excipients
- Adds “one or more pharmaceutically acceptable excipients.”
Claim 11: PI3K inhibitor
- Limits the medicament to one where the active ingredient is a PI3K inhibitor.
Claim 12: PI3K-γ inhibitor
- Further narrows to PI3K-γ inhibitor.
From an infringement and licensing stance, these claims:
- enable positioning in kinase-selective licensing discussions
- can support nonliteral infringement arguments where a competitor’s compound is functionally within the PI3K-γ category and the chemical structure fits claim 1.
How strong is the US 7,511,041 patent estate for blocking generics or biosimilars?
US 7,511,041 is a small-molecule chemical composition patent (fused azolepyrimidines), so the relevant exclusivity risk is for ANDA generics rather than biosimilars.
The scope suggests high blocking strength because:
- claim 1 is a broad genus with extensive allowable substituent permutations
- dependent claims and explicit exemplars provide multiple fallback ladders
- claims 9–12 create additional claim targets for marketed drug product compositions containing the active
Generic entry risk is highest where:
- the generic product’s API is the same compound (including salts/isomers)
- or the API is a close structural analog that still falls inside the formula constraints and permitted R-group lists.
Design-around risk is mitigated only if a competitor can:
- change the allowed bond topology (Y2═Y3 behavior), or
- move substituents outside the specified R1/R2 permitted chemistries, or
- adopt a different scaffold that no longer satisfies the formula (I).
Design-around map: which claim parameters are best targets to avoid infringement of US 7,511,041?
Using the provided claim text, the most meaningful design-around “levers” are:
-
Y2═Y3 bond order and valence class
- Switching from the allowed double/single bond behaviors that dictate whether Y2/Y3 can be CR4 or N (double) versus CR3R4 or NR4 (single) can be a clean exit.
-
X substituent class
- Changing X so it cannot be “CR5R6 or NH” knocks out claim 1 and all dependents.
-
Z1–Z4 assignment
- If the fused scaffold positions mapped to Z1–Z4 are altered such that some positions can’t be CH/CR2/N, the genus may be avoided.
-
R-group boundaries
- R1 and R2 are broad, but they still have definitional constraints and included substituent classes.
- The most credible design-around is usually not deleting the scaffold but adjusting functional groups so they do not meet the enumerated “optionally substituted by …” sets.
Key takeaways
- US 7,511,041 is a genus composition-of-matter patent over fused azolepyrimidine derivatives with extensive R1/R2 substituent latitude plus explicit capture of tautomers, stereoisomers, and salts.
- Claim 1 is the primary enforcement anchor; claims 2–7 are structural narrowing layers that constrain bond topology, positional CH/CR2/N assignments, and hydrogen settings for R3–R6, reducing risk of overbreadth while preserving coverage.
- Claim 8 lists a large set of specific exemplified compounds centered on 7,8-dimethoxy-2,3-dihydroimidazo[1,2-c]quinazoline derivatives with nicotinamide and pyridinyl-vinyl/ethylenol substitution patterns and multiple functional variants.
- Claims 9–12 extend protection to medicaments with the claimed active, and label the active as PI3K inhibitor and specifically PI3K-γ inhibitor, strengthening product-form and licensing leverage for kinase-selective programs.
- The strongest infringement scenarios are those where the competitor API matches the scaffold and remains within the Y2═Y3 / Z-position / X-class constraints and the permitted R1/R2 functional substitution categories.
FAQs
1) Does US 7,511,041 cover salts and stereoisomers?
Yes. Claim 1 expressly includes “tautomeric or stereoisomeric form” and “a salt thereof,” and claims 2–8 inherit that coverage language.
2) What structural element is most critical for staying within the claim?
The Y2═Y3 bond condition in claim 1: the permitted atom classes for Y2 and Y3 depend on whether the bond is double or single.
3) Are PI3K-γ inhibitors covered as medicaments?
Yes. Claims 11 and 12 require the active ingredient in the medicament to be a PI3K inhibitor and specifically a PI3K-γ inhibitor.
4) Are specific named compounds protected beyond the genus?
Yes. Claim 8 enumerates many specific fused azolepyrimidine derivatives, creating defined targets in addition to the broad formula coverage.
5) What is the likely practical risk to ANDA applicants for small molecules?
Where an ANDA applicant uses an API that fits the formula (I) and the claim-defined scaffold constraints, the genus-plus-exemplars structure in claims 1 and 8 can support infringement even if only particular R-group decorations differ.
References
- United States Patent 7,511,041. “Fused azolepyrimidine derivatives,” claims 1–12 (as provided in the prompt).
