US Patent 7,300,935: Scope, Claim Construction, and US Patent Landscape
What do claims 1 and 2 actually cover?
US Patent 7,300,935 contains two compound claims that are narrow in structure but broad in salt coverage. Both claims are directed to substituted, bicyclic heteroaryl urea derivatives built on a tetrahydrothieno[2,3-d]pyrimidin core with specific aryl and heteroaryl substitutions and a defined urea motif.
Claim 1 (structural anchor and substituent map)
Claim 1 covers:
- Core scaffold: 1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin
- Position 6 substitution: a (2,6-difluorobenzyl) group and a fused substitution logic giving:
- 3-(2-pyridinyl)
- 5-((2-ethoxyethyl)(methyl)amino)methyl)
- 6-yl linked to phenyl
- Terminal urea: N′-methoxyurea
- Phenyl substitution: the phenyl ring is substituted with the tetrahydrothieno[2,3-d]pyrimidin-6-yl linkage and an N-urea-forming anilide nitrogen
- Salt: claim includes “or a salt thereof”
Claim text (as provided by you, paraphrase anchored to key groups):
N-(4-(1-(2,6-difluorobenzyl)-5-(((2-ethoxyethyl)(methyl)amino)methyl)-2,4-dioxo-3-(2-pyridinyl)-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl)phenyl)-N′-methoxyurea (and salts)
Functional implication: Claim 1 is not a genus for the whole class of urea derivatives; it is a single-chemotype claim that locks:
- the difluorobenzyl identity (positioning at 2,6),
- the heteroaryl at position 3 (2-pyridinyl),
- the amine side-chain identity at position 5 ((2-ethoxyethyl)(methyl)amino methyl),
- the urea N-substitution (methoxy on the urea nitrogen).
Claim 2 (alternate substituent set on the same scaffold)
Claim 2 covers a closely related analogue with:
- Core scaffold: same tetrahydrothieno[2,3-d]pyrimidin
- Position 6 substitution logic: still includes
- 1-(2,6-difluorobenzyl)
- 2,4-dioxo
- 6-yl linked to phenyl
- 3-heteroaryl switched: 3-(6-methoxy-3-pyridazinyl) (instead of 3-(2-pyridinyl))
- 5-position side chain changed: 5-((dimethylamino)methyl) (instead of (2-ethoxyethyl)(methyl)amino methyl)
- Terminal urea: still N′-methoxyurea
- Salt: “or a salt thereof”
Claim text (as provided by you, paraphrase anchored to key groups):
N-(4-(1-(2,6-difluorobenzyl)-5-((dimethylamino)methyl)-3-(6-methoxy-3-pyridazinyl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl)phenyl)-N′-methoxyurea (and salts)
Functional implication: Claim 2 remains a single-chemotype claim; it locks two specific structure changes relative to claim 1 while maintaining the same urea type and difluorobenzyl linkage.
How would a court likely construe the scope limits?
1) The “structure-first” boundaries are explicit
Both claims are drafted as full chemical names. The scope is therefore constrained to:
- exact ring system: thieno[2,3-d]pyrimidin with 1,2,3,4-tetrahydro
- exact oxidation pattern: 2,4-dioxo
- exact substitution pattern: difluorobenzyl at 1, heteroaryl at 3, sidechain at 5, phenyl linkage at 6
- exact urea N-substitution: N′-methoxyurea
- exact phenyl connection: 4-( … phenyl ) with the tetrahydrothieno[2,3-d]pyrimidin-6-yl attached to that phenyl
A design-around is therefore most plausibly achieved by altering at least one of these locked elements (especially the urea N-substitution, the 2,6-difluorobenzyl, the 3-heteroaryl, or the 5-amine sidechain).
2) “Or a salt thereof” expands coverage but not the core structure
Salt coverage typically does not permit substitution of the core molecule; it extends to pharmaceutically acceptable acid/base salts of the claimed compound. For risk analysis, treat the claims as covering:
- the free base structure as named
- its salt forms (no change to connectivity beyond ion pairing)
3) The claims do not read as broad “substituent class” claims
The claims do not say “where R is …” in a way that yields a broad genus. Instead, each claim is a single, fully specified compound. That matters for:
- infringement analysis (literal infringement requires matching the complete structure)
- validity analysis (prior art that hits the scaffold but differs in key substituents may avoid anticipation, though it could still affect obviousness if close)
What is the likely claim-by-claim infringement “switchboard”?
A fast way to map infringement risk is to treat each claim as a checklist.
Claim 1 infringement checklist (must match)
- Urea terminal: N′-methoxyurea
- Core: 1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin
- Oxos: 2,4-dioxo
- Position 1 substituent: 2,6-difluorobenzyl
- Position 3 substituent: 2-pyridinyl
- Position 5 substituent: -CH2- attached to (2-ethoxyethyl)(methyl)amino group (i.e., the side chain is not dimethylamino and not a different alkoxyalkyl)
- Position 6 substituent: linked through phenyl at 4- position
Claim 2 infringement checklist (must match)
All of the above items, except:
- Position 3: 6-methoxy-3-pyridazinyl
- Position 5: dimethylamino methyl (no 2-ethoxyethyl group; no N-methyl + N-(2-ethoxyethyl) amino)
This means a compound that swaps only the 3-heteroaryl could fall within claim 2 but not claim 1, and vice versa.
What is the likely patent landscape impact in the US?
Because the provided record limits analysis to just the two claims you supplied, a complete, source-cited landscape (competing assignees, continuation families, blocking patents, and expiration timelines) cannot be constructed without the bibliographic record of US 7,300,935 (filing/priority date, assignee, prosecution history, and reference citations). The landscape discussion below therefore focuses on scope-driven positioning and practical freedom-to-operate (FTO) design constraints that derive directly from the claim language.
Landscape segmentation by structure “hot spots”
US 7,300,935 is best treated as protecting a small cluster of close analogues:
- Same scaffold and urea motif
- Two specific variants:
- Claim 1: 2-pyridinyl + (2-ethoxyethyl)(methyl)amino methyl
- Claim 2: 6-methoxy-3-pyridazinyl + dimethylamino methyl
That pattern implies that other patents in the space (from the same or different entities) likely fall into one of three zones:
- Same urea motif and scaffold, different 3-heteroaryl
- Same scaffold and difluorobenzyl, different 5-sidechain amino substitution
- Same overall heterocycle, different C2/C4 carbonyl pattern or different substitution at position 1/6
For competitive compounds, the strongest non-infringing moves are usually:
- changing the 3-heteroaryl (2-pyridinyl versus 6-methoxy-3-pyridazinyl is already a key variable)
- changing the 5-sidechain amine identity/alkylation state
- changing the urea N-substitution pattern away from N′-methoxyurea
- changing the difluorobenzyl substitution pattern (2,6 positions)
Design-around strategy logic (based strictly on claim locking)
A developer seeking to avoid both claims should treat the following as “do not touch” only if they want infringement risk:
- Keep none of these elements constant across both claims:
- N′-methoxyurea
- 1-(2,6-difluorobenzyl)
- 3-(2-pyridinyl) or 3-(6-methoxy-3-pyridazinyl)
- 5-amine sidechain (either variant)
Any deviation in a locked position can take a compound out of literal scope, but may still face a doctrine-of-equivalents theory depending on how substitution is argued in litigation. Because these claims are compound-specific, equivalence risk generally rises when the alternative substitution is a minor chemistry change with predictable pharmacological and structural equivalence.
What do the claims suggest about enforceable “coverage geometry”?
1) Narrow compound claims mean limited literal coverage
If a competitor uses a different urea N-substitution (not methoxyurea) or does not maintain the exact 2,4-dioxo tetrahydrothieno[2,3-d]pyrimidin scaffold, literal infringement is less likely.
2) The two claims show a targeted SAR window
The pair of claims points to a SAR corridor where:
- a difluorobenzyl is a stable pharmacophore
- switching heteroaryl at position 3 and amine substitution at position 5 is tolerated while maintaining biological effect
- urea N-methoxylation is treated as structurally important
For portfolio strategy, this typically means the next layer of patents (from the same family or related filings) either:
- expands the permitted heteroaryl/amine combinations, or
- claims additional analogues with the same scaffold.
Practical “freedom-to-operate” implications for US 7,300,935
Infringement probability tiers for a generic competitor (structure-based)
- High risk: compounds that keep the full scaffold and urea motif and match both the 2,6-difluorobenzyl and one of the two claimed (3-heteroaryl + 5-amine) combinations.
- Medium risk: compounds that match most elements but change only one locked variable (commonly position 3 heteroaryl or position 5 sidechain).
- Lower risk: compounds that change the urea N-substitution away from N′-methoxyurea or that change the difluorobenzyl substitution pattern or the core carbonyl pattern.
Filing strategy for a design-around molecule
A “safe-by-design” route generally changes at least one of the high-impact features:
- urea N-substitution
- the difluorobenzyl
- the position 3 heteroaryl
- the position 5 amino substituent
Key Takeaways
- US 7,300,935 contains two compound claims that are fully specified and therefore tightly constrained to defined substitution patterns on a tetrahydrothieno[2,3-d]pyrimidin scaffold with 2,4-dioxo carbonyls and N′-methoxyurea.
- Claim 1 protects the exact pairing 3-(2-pyridinyl) + 5-(((2-ethoxyethyl)(methyl)amino)methyl) with 1-(2,6-difluorobenzyl).
- Claim 2 protects the analogue with 3-(6-methoxy-3-pyridazinyl) + 5-((dimethylamino)methyl) while keeping the same urea motif and difluorobenzyl substitution.
- “Or a salt thereof” expands coverage to salts of those exact structures but does not broaden the chemical structure beyond the named scaffold and substituents.
- The enforceable coverage geometry is best understood as a narrow SAR corridor: maintain the core and urea motif, and be careful around the position 3 heteroaryl and position 5 amine sidechain combinations.
FAQs
1) Do claims 1 and 2 cover a whole class of tetrahydrothieno[2,3-d]pyrimidin urea derivatives?
No. Each claim is a fully specified compound with fixed substituents and only salt forms added.
2) If a compound matches the core and urea motif but swaps the 3-heteroaryl, does it infringe?
It will not fall within that specific claim’s literal scope if it does not match the exact 3-substituent named in the claim (2-pyridinyl in claim 1; 6-methoxy-3-pyridazinyl in claim 2).
3) What is the role of “or a salt thereof”?
It extends coverage to pharmaceutically acceptable salts of the exact claimed molecule.
4) Which elements are most critical for avoiding literal infringement?
The urea N-substitution (N′-methoxyurea), the 1-(2,6-difluorobenzyl) group, the 3-heteroaryl, and the 5-amine sidechain are the highest-impact structural locks.
5) How many distinct chemotypes are claimed?
Two, corresponding to the two specific combinations of position 3 and position 5 substituents, while holding the urea motif and core scaffold constant.
References
- US Patent 7,300,935. Claims provided in the prompt (Claim 1 and Claim 2 text).
